Summer months bring more than hot, sticky weather, they also bring the air conditioner repairmen
The stranger wandering around George Charkalis’ two-story red brick home, tinkering with his air conditioning unit, was a welcome sight.
“It’s cooling well downstairs but not upstairs,” Charkalis, who co-owns Greek Bros. restaurant with his wife Blanche, said on May 22.
Yes, the warmer weather has reared its head in Victoria and, in addition to outdoor picnics and summer break, it brings added work for air conditioner technicians.
Residential repairs begin to pick up between mid-April and early May, said Jonathan Pozzi, office manager at Crossroads Mechanical, Incorporated.
And the common complaint, he said, is that the air conditioner isn’t cooling.
Crossroads Mechanical receives about four to five calls a day during mild months, he said, but that jumps to between seven and 10 once things heat up.
“We’ve had three already today, on top of what we already had scheduled,” he said on May 21. “Nobody wants to be without cold air.”
Aged equipment often breaks with the first heat wave, he said, but there are things people can do to keep their systems up to par.
Change your air filters monthly, Pozzi said, because clogged filters make the air conditioner work harder.
Keeping a clean condensate drain line is also important, he said.
But most importantly: have your system checked out regularly.
“Preventive maintenance is the No. 1 key,” Pozzi said. “Make sure things are working well before it gets hot.”
Many repair companies offer maintenance contracts where workers evaluate heating and cooling systems before extreme weather hits.
But there are some things you can’t change.
When certain parts such as compressors go out, you need to get a new unit or change out the compressor.
An air system’s average life expectancy is between 15 and 20 years, said Ricky Arredondo, a service technician with Crossroads Mechanical.
The recent heat means 12 and 13-hour workdays for Roger Meyer, who owns ACR Heating & Air Conditioning.
“The slowest times for us are January, February and March,” he said. “Right now we’re busy. Very, very busy.”
Victoria’s shortage of qualified workers contributes to Meyer’s extended hours, he said.
The Golden Crescent region’s unemployment rate hit 3.1 percent in April, and Meyer said the state requires employers to perform background checks on potential employees.
“And the help must be certified,” he said. “But we just can’t find qualified people. That’s part of the problem, partly why we’re so busy.”
Homeowners with ailing air conditioners aren’t the only ones braving the Texas heat.
Repair company employees find themselves in extreme heat, too, Pozzi said.
Inside units are often located inside attics, which can reach well above the 100 degree mark.
“It can take an average of an hour or so to fix a unit,” Pozzi said. “But that can seem like an eternity to our guys.”
Techs are encouraged to take water jugs along with them, he said, and to take breaks when possible.
“Depending on the heat, if they have to come down every five or 10 minutes, they do,” he said. “We stress safety.”
Arredondo said his working conditions at the Charkalis home were better than what he’s experienced in other places.
The family’s attic is large, he said, which means better ventilation. Smaller spaces which require repairmen to “army crawl” to get through can sometimes reach 160 degrees.
“I’ve got a cooler full of Gatorade in my truck,” he said. “I’ve got about five stops to make today, but the weather is better than it has been.”
And as for Charkalis, he said he’s glad to get the system fixed.
“We wanted to fix it before it got too hot,” he said. “I was surprised. I called yesterday and they said they could come out today.”
Saturday, May 31, 2008
Wednesday, May 28, 2008
To R22 or not to R22 that is the question
AC Refrigerant?
Posted by fedude (My Page) on
Tue, May 27, 08 at 8:57
Building a new house (1800sqft ranch) in upstate NY. My builder has suggested a "Rheem or equal 13 sheer 3 ton R22 Freeon". Not sure specifically what model this is but I have two questions?
1) Is the R22 Freeon OK, or should I request the R-410a refrigerant? Does refrigerant ever need to be replaced?
2) I can upgrade to a 16 sheer 3-ton for $912. Would it be worth it?
Follow-Up Postings:
o
RE: AC Refrigerant?
* Posted by tigerdunes (My Page) on
Tue, May 27, 08 at 9:16
fedude
R-410a refrigerant with 14-15 SEER and a var speed blower on furnace...
what furnace are you looking at-the Rheem Mod?
the refrigerant used on an AC or HP condenser/evap coil is a closed system and never needs to be replaced unless there is a leak or possibly a contamination issue.
IMO
o
RE: AC Refrigerant?
* Posted by funnycide (My Page) on
Tue, May 27, 08 at 16:40
don't worry about refrigerant. R-22 is fine
will this be a heat pump or furnace (nat gas or propane)?
o
RE: AC Refrigerant?
* Posted by fedude (My Page) on
Tue, May 27, 08 at 22:19
Furnace with natural gas. No heat pump.
I'm going to try to get a variable speed blower.
Anything else I should look for? I don't know what model. I'll find out in the next week or so. Are there any I should ask for (or ones to avoid?)
o
RE: AC Refrigerant?
* Posted by miken_2008 (My Page) on
Wed, May 28, 08 at 7:39
R22 is fine now but the price has increased four fold in the last two years and this system will leak probably after five years then what will the cost of R22 be the supply will be so greatly reduced that it will probably be somewhere around $700 for a 30# drum better to make the right decision now prices for 410a and 134a are going down while R22 goes up and for those of us who were around for the R12 phase out we know how that will play out people who make the wrong decisions in the transition pay a high price later
Here is a link that might be useful: Air Conditioning Repair made Easy
Posted by fedude (My Page) on
Tue, May 27, 08 at 8:57
Building a new house (1800sqft ranch) in upstate NY. My builder has suggested a "Rheem or equal 13 sheer 3 ton R22 Freeon". Not sure specifically what model this is but I have two questions?
1) Is the R22 Freeon OK, or should I request the R-410a refrigerant? Does refrigerant ever need to be replaced?
2) I can upgrade to a 16 sheer 3-ton for $912. Would it be worth it?
Follow-Up Postings:
o
RE: AC Refrigerant?
* Posted by tigerdunes (My Page) on
Tue, May 27, 08 at 9:16
fedude
R-410a refrigerant with 14-15 SEER and a var speed blower on furnace...
what furnace are you looking at-the Rheem Mod?
the refrigerant used on an AC or HP condenser/evap coil is a closed system and never needs to be replaced unless there is a leak or possibly a contamination issue.
IMO
o
RE: AC Refrigerant?
* Posted by funnycide (My Page) on
Tue, May 27, 08 at 16:40
don't worry about refrigerant. R-22 is fine
will this be a heat pump or furnace (nat gas or propane)?
o
RE: AC Refrigerant?
* Posted by fedude (My Page) on
Tue, May 27, 08 at 22:19
Furnace with natural gas. No heat pump.
I'm going to try to get a variable speed blower.
Anything else I should look for? I don't know what model. I'll find out in the next week or so. Are there any I should ask for (or ones to avoid?)
o
RE: AC Refrigerant?
* Posted by miken_2008 (My Page) on
Wed, May 28, 08 at 7:39
R22 is fine now but the price has increased four fold in the last two years and this system will leak probably after five years then what will the cost of R22 be the supply will be so greatly reduced that it will probably be somewhere around $700 for a 30# drum better to make the right decision now prices for 410a and 134a are going down while R22 goes up and for those of us who were around for the R12 phase out we know how that will play out people who make the wrong decisions in the transition pay a high price later
Here is a link that might be useful: Air Conditioning Repair made Easy
Saturday, May 17, 2008
Now you know why R 22 is so expensive
Refrigerant Deadline Pushes the HVACR Industry to Prepare
As 13 SEER came down the pike in 2006, contractors and distributors, operating on scattered timetables, took multiple approaches to preparing for the new industry requirements. The only commonality was the inevitability of the shift, and on Jan. 23, 2006, 13 SEER became the new 10 SEER. Faced with yet another transitional challenge, the industry is making new efforts to prepare for 2010, the next step in R-22 phaseout. With considerable efforts and diverse strategies, contractors and distributors are beginning to abandon procrastination and embrace the unavoidable — R-410A will soon be the new R-22.
DOLLARS AND CENTS
Last year, Emerson Climate Technologies began surveying contractors and distributors in an effort to gauge their R-22 phaseout preparedness. In May of 2007, the manufacturer’s 2010 Refrigerant Transition Survey found that although everyone seemed to know about the impending change, 40 percent of those surveyed determined that they would wait until the 2010 deadline before converting their sales to R-410A equipment. In the November release, however, the numbers shifted somewhat and the urgency to meet the 2010 deadline ramped up as customers began demanding R-410A equipment.
According to Emerson’s research, 15 percent of those surveyed — up from 10 percent in May — reported that more than 40 percent of their customers are requesting R-410A equipment.
Enlarge this picture
“End-users are placing increasing importance on equipment being more efficient and environmentally friendly,” said the manufacturer. “They are also growing more aware that R-22 refrigerant availability will affect the price, making R-22 equipment expensive to maintain.”
In fact, Emerson reported that two-thirds of those surveyed said they cite both environmental concerns and long-term costs when explaining the benefits of R-410A equipment to their customers.
According to respondents, “maintenance expenses” and “being better for the environment” are the two most popular R-410A selling points. Other selling points include efficiency, new technology arguments, a better and longer warranty, improved comfort level, and longer life and greater reliability. Nine percent said they did not promote or sell R-410A and 24 percent of the respondents said their customers don’t ask for R-410A. As awareness increases, however, this number decreases, as evidenced in the 3 percent drop from the May 2007 report.
R-410A RECOMMENDED
Enlarge this picture
Selling R-410A requires some new tactics, and when more than one-third of the industry (39 percent) is still intending to wait until 2010 to convert the majority of their sales to R-410A equipment, Emerson questioned respondents as to why they recommend R-22 over R-410A.
“The predominant answers were retrofit concerns and short-term economics,” said the manufacturer. “They pointed to the fact that R-22 has a lower price to their customers for outdoor and indoor equipment.”
According to Emerson, however, “the cost picture changes when discussing refrigerants themselves.” The survey shows that contractors and distributors are reporting a steady and dramatic price increase, ranging from 20 to 100 percent, in the past few years.
“With contractors and distributors already reporting significant price increases for replacement R-22 refrigerant, the industry must focus on the realities of long-term cost and availability of replacement parts and refrigerant, and thus the importance of making the switch to HFCs like R-410A as quickly as possible,” said Scott Barbour, president, Emerson Climate Technologies Air Conditioning Division.
Cost isn’t the only concern that contractors and distributors are facing. The surveyed respondents also reported being extremely concerned with retrofits, future availability of R-22, full model line availability of R-410A commercial and residential equipment, equipment failures due to improper installation, increased repair of R-22 versus replacement with R-410A, changes in refrigerant characteristics, and inadequate training or skills. In spite of these and other concerns, the survey reported that 64 percent of the respondents are currently training their staff to service and install R-410A equipment.
“We are glad to see that more HVAC professionals are beginning to transition their business toward R-410A-bearing equipment in advance of 2010,” said Barbour. “This latest survey tells us that the industry is accelerating the transition, but we need to continue increasing the forward momentum to ensure we are all prepared to provide the best, most responsible options for our customers.”
As 13 SEER came down the pike in 2006, contractors and distributors, operating on scattered timetables, took multiple approaches to preparing for the new industry requirements. The only commonality was the inevitability of the shift, and on Jan. 23, 2006, 13 SEER became the new 10 SEER. Faced with yet another transitional challenge, the industry is making new efforts to prepare for 2010, the next step in R-22 phaseout. With considerable efforts and diverse strategies, contractors and distributors are beginning to abandon procrastination and embrace the unavoidable — R-410A will soon be the new R-22.
DOLLARS AND CENTS
Last year, Emerson Climate Technologies began surveying contractors and distributors in an effort to gauge their R-22 phaseout preparedness. In May of 2007, the manufacturer’s 2010 Refrigerant Transition Survey found that although everyone seemed to know about the impending change, 40 percent of those surveyed determined that they would wait until the 2010 deadline before converting their sales to R-410A equipment. In the November release, however, the numbers shifted somewhat and the urgency to meet the 2010 deadline ramped up as customers began demanding R-410A equipment.
According to Emerson’s research, 15 percent of those surveyed — up from 10 percent in May — reported that more than 40 percent of their customers are requesting R-410A equipment.
Enlarge this picture
“End-users are placing increasing importance on equipment being more efficient and environmentally friendly,” said the manufacturer. “They are also growing more aware that R-22 refrigerant availability will affect the price, making R-22 equipment expensive to maintain.”
In fact, Emerson reported that two-thirds of those surveyed said they cite both environmental concerns and long-term costs when explaining the benefits of R-410A equipment to their customers.
According to respondents, “maintenance expenses” and “being better for the environment” are the two most popular R-410A selling points. Other selling points include efficiency, new technology arguments, a better and longer warranty, improved comfort level, and longer life and greater reliability. Nine percent said they did not promote or sell R-410A and 24 percent of the respondents said their customers don’t ask for R-410A. As awareness increases, however, this number decreases, as evidenced in the 3 percent drop from the May 2007 report.
R-410A RECOMMENDED
Enlarge this picture
Selling R-410A requires some new tactics, and when more than one-third of the industry (39 percent) is still intending to wait until 2010 to convert the majority of their sales to R-410A equipment, Emerson questioned respondents as to why they recommend R-22 over R-410A.
“The predominant answers were retrofit concerns and short-term economics,” said the manufacturer. “They pointed to the fact that R-22 has a lower price to their customers for outdoor and indoor equipment.”
According to Emerson, however, “the cost picture changes when discussing refrigerants themselves.” The survey shows that contractors and distributors are reporting a steady and dramatic price increase, ranging from 20 to 100 percent, in the past few years.
“With contractors and distributors already reporting significant price increases for replacement R-22 refrigerant, the industry must focus on the realities of long-term cost and availability of replacement parts and refrigerant, and thus the importance of making the switch to HFCs like R-410A as quickly as possible,” said Scott Barbour, president, Emerson Climate Technologies Air Conditioning Division.
Cost isn’t the only concern that contractors and distributors are facing. The surveyed respondents also reported being extremely concerned with retrofits, future availability of R-22, full model line availability of R-410A commercial and residential equipment, equipment failures due to improper installation, increased repair of R-22 versus replacement with R-410A, changes in refrigerant characteristics, and inadequate training or skills. In spite of these and other concerns, the survey reported that 64 percent of the respondents are currently training their staff to service and install R-410A equipment.
“We are glad to see that more HVAC professionals are beginning to transition their business toward R-410A-bearing equipment in advance of 2010,” said Barbour. “This latest survey tells us that the industry is accelerating the transition, but we need to continue increasing the forward momentum to ensure we are all prepared to provide the best, most responsible options for our customers.”
Thursday, May 15, 2008
Green Tips for Air Conditioning
ASHRAE Building-Type GreenTip #1:
Performing Arts Spaces
GENERAL DESCRIPTION
Performing arts spaces include dance studios, black box theaters, recital halls,
rehearsal halls, practice rooms, performance halls with stage and fixed seating,
control rooms, back-house spaces, and support areas.
HIGH-PERFORMANCE STRATEGIES
Acoustics
1. Clearly understand different criteria for noise criteria levels to be achieved in
different type of spaces.
2. Consider 2 and 4 in. liners for large ducts serving spaces with noise criteria
levels of 25 and lower.
3. Locate equipment as far away from low noise criteria spaces as practical.
4. Work closely with the acoustic consultant, structural engineer, architect, and
construction manager to integrate strategies that eliminate the distribution of vibration
and equipment noise from the HVAC systems to the performance spaces.
5. Design duct distribution to eliminate noise transfer between acoustically sensitive
spaces. This can be done by using duct liner, additional elbows to isolate
sound travel, sound attenuators, etc.
6. Do not route piping systems through or above spaces that are acoustically sensitive.
Performing Arts Spaces
GENERAL DESCRIPTION
Performing arts spaces include dance studios, black box theaters, recital halls,
rehearsal halls, practice rooms, performance halls with stage and fixed seating,
control rooms, back-house spaces, and support areas.
HIGH-PERFORMANCE STRATEGIES
Acoustics
1. Clearly understand different criteria for noise criteria levels to be achieved in
different type of spaces.
2. Consider 2 and 4 in. liners for large ducts serving spaces with noise criteria
levels of 25 and lower.
3. Locate equipment as far away from low noise criteria spaces as practical.
4. Work closely with the acoustic consultant, structural engineer, architect, and
construction manager to integrate strategies that eliminate the distribution of vibration
and equipment noise from the HVAC systems to the performance spaces.
5. Design duct distribution to eliminate noise transfer between acoustically sensitive
spaces. This can be done by using duct liner, additional elbows to isolate
sound travel, sound attenuators, etc.
6. Do not route piping systems through or above spaces that are acoustically sensitive.
Wednesday, May 14, 2008
Some Ductwork Help for Dummies
Air Filter Rack Sizing
I realize this will never happen if you use the furnace filter size; however, Air Filter Rack Sizing for efficient operation - Size Gross Return Air filter grille area for 200-sq. ins. per ton. For a 5-Ton system, that would mean Two filter racks 25X20's each, I would go with Two racks & 25X25's each.
Keep air velocities through the filter(s) as low as possible. It is a good idea to Size the Filter rack for a Free Air Area with a Velocity of 350-FPM or less.
A 5-Ton system requires two filter racks to achieve a low enough air velocity through those filters. Most 5-Ton systems nearly always have too much air velocity through initial clean filters, let alone when they begin loading.
ACCA Manual D specifies a maximum Return grille velocity of less than 500 ft per minute and a maximum Supply outlet of 700 ft per minute (fpm) or less.
All filter mfg'ers should print the free air area of the clean filter on the edge of the filter along with the pressure drop data. Divide the rated CFM the duct is carrying by the free area sq.ft. of the filter for airflow velocity in FPM. (Or use above forumula with the duct's sq.ft. area for duct airflow velocity)
Velocity in FPM = Known designed CFM to room divided / by Sq. feet of duct area.
I.E., 8" duct 8x8 = 64 x .7854 = 50.26-sq. In. area / 144 = 0.3490666-sq.feet | designed CFM to room is 173-CFM X's .3490666 = Velocity of 495.6-FPM, you can use a ductulator to get the actual Friction Rates (FR).
Formula for finding CFM Airflow and/or Velocity in FPM
If you can measure the air velocity coming from a duct, here is a rough ballpark formula to get the CFM:
CFM = (velocity in (FPM) Feet per Minute times the square footage of the duct area)
I.E., 16" Rd duct 201-sq.ins. / 144 = 1.3958333-sq.ft. X's Velocity of 800-fpm = 1116-CFM
Times 1000-FPM = 1395-CFM. Branch ducts: 7" Rd duct 38.48-sq. ins. = 0.2672222-sq.ft. X's 500-fpm=133-cfm
All filter mfg'ers should print the free air area of the clean filter on the edge of the filter along with the pressure drop data. Divide the rated CFM the duct is carrying by the free area sq.ft. of the filter for airflow velocity in FPM.
Remember:
When sizing ducts, the use of one Fiction Rate value throughout will usually guarantee incorrect duct size, velocities & CFMs for some duct run segments. If Supply Side is 0.05" per 100 ft of duct run, or less is used, some runouts of the system may be oversized, creating zones that are too cold in summer. Usually the furthest from the air handler will be undersized creating zones that are too warm in summer. Install dampers in all Supply Air ducts for some balancing.
That is an incorrect design. The modified equal friction method of Manual D requires that the Available Static Pressure (ASP) from the fan be "consumed" by the duct through its run from fan to outlet/inlet, with no shortage or excess at the end. Also, pressure drop per 100 ft is not an input--it is a calculated intermediate value.
A contractor or Tech who knows how to do the proper calculations to determine the available static pressure - ASP and correctly allocate it to supply and return, is a very rare Tech indeed. First, select the CFM & velocities you want, that may result in small Friction Rate variations on the various Branch Runs & run lengths.
Always use "Manual D" for proper FRs & duct sizing for required CFMs to each room.
I used figures & formulas below for the table, & wanted 450-Btuh wet coil per ton airflow
Converting square duct inches to round duct size, i.e., an 8" x 8" duct = 64 -sq.ins. x .7854 = 50.26 sq. ins. You round off to 50 sq. ins. for an 8" duct.
Round duct diameter to Sq. Ins., duct diameter 6"x6" = 36 X's .7854 = 28.27-sq. ins.
CFM = (velocity in (FPM) Feet per Minute times the square footage of the duct area)
Quick method: The heat gain and Btu/hr of cooling is done for each room.
Use 30-Btu/hr for each Cubic Foot per Minute (CFM) of Airflow.
Duct Sizing Chart for Approximately 425 to 450-CFM Wet Coil Per Ton on Main Runs
BTUH
CFM
Rd. DIA.
Sq"
Vel/FPM
1290
43
4" BR. Outlets
12.5
493
2031
68
5
19.6
499
2910
97
6"
28
489
10x8
12x7
9x9
3200
106
6" Br
28
540
14x2
7x4
4008
134
7" Br
38.48
502
10x4
8x6
7x6
5200
173
8" Br
50
496
7x7
10x6 8x7
6666
222
9" Br
64
505
8x8
10x7
12x6
9812
327
10" Br
78.5
600
14x6 12x8
16x5
18000
700
13"Metal SA|RA 14" 154-sq"
201 RA
RA 502
RA 14x11
12x12 18X8
16X9
24000
900
14" Metal SA/RA 16" 201 RA
RA 645
RA 14x14
18x10
20x8
14x12
32000 1125
16" metal SA/RA 20"
254 RA
RA 20" 516 RA 14x18
20x10 21x11
36000
1350
18" SA RA 22" 380"
254 SA
RA 22" 512 24X11
16X16
18x14
42000
1575 18" metal SA/RA 22"
380 RA
RA 597
14x22
16x16
48000
1800
20" SA/RA 24"
380 RA
RA 573
14x27
20X19
60000
2000 22" SA/RA 24" 452-sq.ins. 452 RA
RA 637 RA 14x32
16x30
22x21
Solving for Available Static Pressure (ASP) - When Designing or Redesigning Duct Systems, TEL, FR:
Find the Total Return and Supply Lengths by measuring duct, runouts, and adding transitions, turning elbows with or without turning vanes, trunk take-offs, and boots, diffuser pressure drops, filters, etc.
Once you have all the correct Pressure Drops (PDs) for those lengths & devices, use the manufacturer's nameplate pressure (IWC) or .5" ESP and subtract all airstream device pressure losses (filters, wet coil, etc. all available in manual D) from that given value. That will leave the "Available Static Pressure" - ASP for duct & blower design purposes.
You can figure the Total Equivalent Length (TEL) by using the Manual D length additives for the various fittings, then use your Duct Designer ductulator to properly size the duct system to meet the velocities and CFMs required in respect to the blower's Nameplate ESP and its performance graph data.
There are charts available to determine what the total pressure drop will be when you figure the "Total Equivalent Length" run of the longest Supply duct runs; ALL lengths of duct and ALL fittings for turning, reductions, etc., have a Total Effective Length (TEL) additive to the duct length - that must be added to the regular length of that duct run!
The best thing to do is figure your available static pressure. using .5” ESP is good, because most furnaces are designed for .5" ESP to get desired CFM, if needed, you can always use a lower blower speed. You subtract any external pressure drops to the furnace evap coil, filter, registers, dampers, anything outside of furnace cabinet.
Then get a total equivalent length of your ductwork most ductulators have this on the back of them. Friction Rate = Available Static Pressure times X’s 100; divided by the TEL, that is the friction rate per 100 ft of SA & RA duct.
I realize this will never happen if you use the furnace filter size; however, Air Filter Rack Sizing for efficient operation - Size Gross Return Air filter grille area for 200-sq. ins. per ton. For a 5-Ton system, that would mean Two filter racks 25X20's each, I would go with Two racks & 25X25's each.
Keep air velocities through the filter(s) as low as possible. It is a good idea to Size the Filter rack for a Free Air Area with a Velocity of 350-FPM or less.
A 5-Ton system requires two filter racks to achieve a low enough air velocity through those filters. Most 5-Ton systems nearly always have too much air velocity through initial clean filters, let alone when they begin loading.
ACCA Manual D specifies a maximum Return grille velocity of less than 500 ft per minute and a maximum Supply outlet of 700 ft per minute (fpm) or less.
All filter mfg'ers should print the free air area of the clean filter on the edge of the filter along with the pressure drop data. Divide the rated CFM the duct is carrying by the free area sq.ft. of the filter for airflow velocity in FPM. (Or use above forumula with the duct's sq.ft. area for duct airflow velocity)
Velocity in FPM = Known designed CFM to room divided / by Sq. feet of duct area.
I.E., 8" duct 8x8 = 64 x .7854 = 50.26-sq. In. area / 144 = 0.3490666-sq.feet | designed CFM to room is 173-CFM X's .3490666 = Velocity of 495.6-FPM, you can use a ductulator to get the actual Friction Rates (FR).
Formula for finding CFM Airflow and/or Velocity in FPM
If you can measure the air velocity coming from a duct, here is a rough ballpark formula to get the CFM:
CFM = (velocity in (FPM) Feet per Minute times the square footage of the duct area)
I.E., 16" Rd duct 201-sq.ins. / 144 = 1.3958333-sq.ft. X's Velocity of 800-fpm = 1116-CFM
Times 1000-FPM = 1395-CFM. Branch ducts: 7" Rd duct 38.48-sq. ins. = 0.2672222-sq.ft. X's 500-fpm=133-cfm
All filter mfg'ers should print the free air area of the clean filter on the edge of the filter along with the pressure drop data. Divide the rated CFM the duct is carrying by the free area sq.ft. of the filter for airflow velocity in FPM.
Remember:
When sizing ducts, the use of one Fiction Rate value throughout will usually guarantee incorrect duct size, velocities & CFMs for some duct run segments. If Supply Side is 0.05" per 100 ft of duct run, or less is used, some runouts of the system may be oversized, creating zones that are too cold in summer. Usually the furthest from the air handler will be undersized creating zones that are too warm in summer. Install dampers in all Supply Air ducts for some balancing.
That is an incorrect design. The modified equal friction method of Manual D requires that the Available Static Pressure (ASP) from the fan be "consumed" by the duct through its run from fan to outlet/inlet, with no shortage or excess at the end. Also, pressure drop per 100 ft is not an input--it is a calculated intermediate value.
A contractor or Tech who knows how to do the proper calculations to determine the available static pressure - ASP and correctly allocate it to supply and return, is a very rare Tech indeed. First, select the CFM & velocities you want, that may result in small Friction Rate variations on the various Branch Runs & run lengths.
Always use "Manual D" for proper FRs & duct sizing for required CFMs to each room.
I used figures & formulas below for the table, & wanted 450-Btuh wet coil per ton airflow
Converting square duct inches to round duct size, i.e., an 8" x 8" duct = 64 -sq.ins. x .7854 = 50.26 sq. ins. You round off to 50 sq. ins. for an 8" duct.
Round duct diameter to Sq. Ins., duct diameter 6"x6" = 36 X's .7854 = 28.27-sq. ins.
CFM = (velocity in (FPM) Feet per Minute times the square footage of the duct area)
Quick method: The heat gain and Btu/hr of cooling is done for each room.
Use 30-Btu/hr for each Cubic Foot per Minute (CFM) of Airflow.
Duct Sizing Chart for Approximately 425 to 450-CFM Wet Coil Per Ton on Main Runs
BTUH
CFM
Rd. DIA.
Sq"
Vel/FPM
1290
43
4" BR. Outlets
12.5
493
2031
68
5
19.6
499
2910
97
6"
28
489
10x8
12x7
9x9
3200
106
6" Br
28
540
14x2
7x4
4008
134
7" Br
38.48
502
10x4
8x6
7x6
5200
173
8" Br
50
496
7x7
10x6 8x7
6666
222
9" Br
64
505
8x8
10x7
12x6
9812
327
10" Br
78.5
600
14x6 12x8
16x5
18000
700
13"Metal SA|RA 14" 154-sq"
201 RA
RA 502
RA 14x11
12x12 18X8
16X9
24000
900
14" Metal SA/RA 16" 201 RA
RA 645
RA 14x14
18x10
20x8
14x12
32000 1125
16" metal SA/RA 20"
254 RA
RA 20" 516 RA 14x18
20x10 21x11
36000
1350
18" SA RA 22" 380"
254 SA
RA 22" 512 24X11
16X16
18x14
42000
1575 18" metal SA/RA 22"
380 RA
RA 597
14x22
16x16
48000
1800
20" SA/RA 24"
380 RA
RA 573
14x27
20X19
60000
2000 22" SA/RA 24" 452-sq.ins. 452 RA
RA 637 RA 14x32
16x30
22x21
Solving for Available Static Pressure (ASP) - When Designing or Redesigning Duct Systems, TEL, FR:
Find the Total Return and Supply Lengths by measuring duct, runouts, and adding transitions, turning elbows with or without turning vanes, trunk take-offs, and boots, diffuser pressure drops, filters, etc.
Once you have all the correct Pressure Drops (PDs) for those lengths & devices, use the manufacturer's nameplate pressure (IWC) or .5" ESP and subtract all airstream device pressure losses (filters, wet coil, etc. all available in manual D) from that given value. That will leave the "Available Static Pressure" - ASP for duct & blower design purposes.
You can figure the Total Equivalent Length (TEL) by using the Manual D length additives for the various fittings, then use your Duct Designer ductulator to properly size the duct system to meet the velocities and CFMs required in respect to the blower's Nameplate ESP and its performance graph data.
There are charts available to determine what the total pressure drop will be when you figure the "Total Equivalent Length" run of the longest Supply duct runs; ALL lengths of duct and ALL fittings for turning, reductions, etc., have a Total Effective Length (TEL) additive to the duct length - that must be added to the regular length of that duct run!
The best thing to do is figure your available static pressure. using .5” ESP is good, because most furnaces are designed for .5" ESP to get desired CFM, if needed, you can always use a lower blower speed. You subtract any external pressure drops to the furnace evap coil, filter, registers, dampers, anything outside of furnace cabinet.
Then get a total equivalent length of your ductwork most ductulators have this on the back of them. Friction Rate = Available Static Pressure times X’s 100; divided by the TEL, that is the friction rate per 100 ft of SA & RA duct.
Monday, May 12, 2008
Air Conditioning Repair
My Air conditioner is not blowing at all and I went outside and there is an ice ball on one of the pipes, what can I do?
Your AC is frozen over on your indoor coil, the first thing to do is go to your thermostat and turn the system switch to off and turn the fan switch to on this will turn the fan on and turn the outdoor unit off this will clear your indoor coil in about two hours.
The coil froze over for a couple of possible reasons you could possibly have had the thermostat turned too low and could have been running the system out of its design parameters this however is the least likely because it would have probably gotten very cold in the house.
You may have low airflow this could be caused by a plugged up filter or a bad blower motor check your filter and make sure your blower is pushing air through the system.
You may be low on refrigerant this would be evidenced by the unit running with good airflow but little or no temperature drop across the unit you will need a set of pressure guages to accurate determine the refrigerant levels
Your AC is frozen over on your indoor coil, the first thing to do is go to your thermostat and turn the system switch to off and turn the fan switch to on this will turn the fan on and turn the outdoor unit off this will clear your indoor coil in about two hours.
The coil froze over for a couple of possible reasons you could possibly have had the thermostat turned too low and could have been running the system out of its design parameters this however is the least likely because it would have probably gotten very cold in the house.
You may have low airflow this could be caused by a plugged up filter or a bad blower motor check your filter and make sure your blower is pushing air through the system.
You may be low on refrigerant this would be evidenced by the unit running with good airflow but little or no temperature drop across the unit you will need a set of pressure guages to accurate determine the refrigerant levels
Friday, May 9, 2008
My outdoor fan is not running
Q. My Air conditioner was working fine last year and I turned it on this year and nothing. I checked the breakers I went outside and found the unit making noise but the outside fan was not running, what do I do.
A. If your outdoor or Pckage unit is making noise then that means it probably has adequate power and the compressor is at least trying to run. Shut off the power and allow the unit to cool down for 1 hour. Restart the power with the thermostat calling for cooling and you standing by the outdoor fan if it tries to start or not use a long thin screwdriver to spin the fan in the direction of rotation and if the fan starts running then you may be able to replace the capacitor and it will be OK if it does not run you need to make sure that you have line voltage going to the fan if so the fan motor will need to be replaced
A. If your outdoor or Pckage unit is making noise then that means it probably has adequate power and the compressor is at least trying to run. Shut off the power and allow the unit to cool down for 1 hour. Restart the power with the thermostat calling for cooling and you standing by the outdoor fan if it tries to start or not use a long thin screwdriver to spin the fan in the direction of rotation and if the fan starts running then you may be able to replace the capacitor and it will be OK if it does not run you need to make sure that you have line voltage going to the fan if so the fan motor will need to be replaced
Thursday, May 8, 2008
Air Conditioning Sizing Help
Correct Sizing of Residential Air Conditioning Systems & Ductwork Systems
Procedures for Proper Ductwork Sizing for Residential Air Conditioning Systems Ductwork Retrofitting Graphed Blower-Curve-Chart - Opportunity
ROOMDUCT CFM - Formula for finding CFM | DUCT SIZING CHARTS | Use "Manual D" | MAIN DUCT CHART | Square Inches Round Duct | Air Filter Rack Sizing DUCTWORK BASICS Basic AC Overview - Specifications VS. Reality | TEL - Solving for ASP Available Static Pressure | SA - RA | Gurgling@TXV
First & foremost of importance is the correct order of proper procedures to follow for optimal efficiency of operation, & long trouble-free equipment performance.
Before you do anything else, educate yourself enough to ensure that you request the proper things be done in the proper order of sequence.
The first procedure is to do everything possible to reduce all sources of heat-gain & heat-loss.
Then have a manual "J" heat-gain load calc done, followed by a Manual "S" for equipment sizing & then a manual "D" for proper ductwork sizing. All registers, grilles, filter racks, & diffusers must be located & sized for optimal efficient performance of the system.
The correct sizing of residential air conditioning systems & ductwork is crucial to ensuring proper indoor space conditioning, equipment performance, and economical operation. Unfortunately, many A/C contractors measure “correct sizing” by the system's ability to meet any indoor thermostat setting at any outdoor temperature. That method of sizing will lead to inefficient operation for the vast majority of conditioning time. Air conditioning systems “must be sized to meet typical or average indoor and outdoor conditions to ensure proper air mixing, filtration and dehumidification of indoor air across seasonal variations.”
For cooling, size the equipment and system based on 100% of the Total Cooling Load (both sensible and latent loads) at actual outdoor design conditions. Size the duct system properly & make certain that he proper airflow & optimal heatload is passing through the evaporator coil during most of the operating runtime. To Optimize Payback and lower operating costs always do as many things as you can to Reduce the heatgain-heatloss "BEFORE doing the manual J load calc & manual S for sizing the equipment."
To select the “proper size” heating, air conditioning, and duct system for a home, seven factors must be considered and all changes made prior to sizing equipment:
1. Improving Insulation Values and Reducing Infiltration, including e-windows, doors, etc.
2. Reducing Air leakage - air leakage accounts for between 25 percent and 50 percent of the energy used for heating and cooling in a typical older residence.
3. Solar orientation - and ways to reduce the radiant heatload should be considered.
4. The Internal BTU heat generation of appliances and people must be added.
5. Design conditions (typical outdoor and indoor weather conditions, humidity levels, etc.) A scientific calculation (manual J) called a Heat Loss/Heat Gain Calc, tabulates these factors into a load scenario for heating and cooling based on summer & winter outdoor design conditions for the climate where the home is located.
By comparing the heat loss/gain to manufacturer's equipment performance data, a properly sized heating and cooling system is selected. Use indoor design of 75-F dry bulb and 63-F wet bulb, around 50% Relative Humidity.
6. Proper & thorough ductwork testing and design Is Extremely Important for efficiency & BTUH performance - The evaporator coil needs to have an optimal heatload passing through it most of the time in order to approach achieving its Rated BTUH Capacities & its EER & SEER Ratings.
7. For optimal comfort in the Air Conditioning mode diffusers should be at or near the ceiling. Study the diffuser data in respect to room CFM, the required throw & a diffuser Face Velocity of around 500-fpm, & a Terminal Velocity at the human occupant level area of 50 to 75-fpm. This is critical toward achieving an optimal human comfort zone.
What should you expect from the average heating and cooling contractor?
When a typical heating and cooling contractor quotes the efficiency of the equipment (SEER or AFUE) and leads you to believe the new equipment will automatically deliver that efficiency, think again. Typical installed equipment only operates at 55% to 70% of rated capacity.
It is important to understand that equipment ratings are only "the potential efficiency of that component of the system under perfect conditions." "Over half of the system's efficiency depends on the duct system and the field-installation." Check for Return Air drawing Hot Air from attic areas, etc.!
An A/C's system efficiency can often be increased by a skilled tech from 10% to 50%. The biggest benefit is the increase in comfort and lower utility bills!
The heat loss/heat gain calculates the amount of heat transfer by component, based on the surface area, and then tabulates the total transfer for all of the components.
Air leakage/air infiltration: Up to 50% of an average home's heat loss/heat gain is attributable to air leakage/air infiltration. Therefore, determining the proper leakage/air infiltration rate for a specific home is paramount. Design leakage/air infiltration rates are based on dwelling size and projected efficiency or actual measured performance.
Solar orientation, or the amount of window surface area and the direction a home faces can have tremendous impact on the cooling needs (heat gain). Similar houses with different solar orientation will have different cooling loads. Glass facing east/west has more heat gain than glass facing south or North.
The service techs should use a manual D to properly size the ductwork supply air mains and runs to outlet diffusers, as well as the “sizing of the return air ducting in relationship to the btuh/cfm requirements of the various rooms.”
Qualified personnel must perform all installations and services. The duct system sizing and load sizing calculation should follow the design standards of Air Conditioning Contractors of America (ACCA) - Manuals D & J -or the American Society of Heating, Refrigeration & Air Conditioning Engineers, Inc. (ASHRAE) Fundamentals Volume (latest edition).
----------
When sizing ducts, the use of one value throughout will assure incorrect duct size for many branch runout duct segments. If 0.05 is used, nearly half of the runouts of the system will be oversized, resulting in those zones being too cold in summer, resulting in the remaining runouts furthermost from the air handler being undersized, creating zones that are too warm in summer.
The result is a human comfort design failure. The modified equal friction method of Manual D, "requires that the available static pressure from the fan be 'consumed' by the duct through its run from fan to outlet/inlet, with no shortage or excess at the end."
Pressure drop per 100 ft is not an input, it is a calculated intermediate value. A contractor who knows how to do the calculations to determine the available static pressure, and correctly allocate it to the supply runouts and return, is a rare tech.
This page does not explain everything you need to know about proper duct sizing a system for optimal comfort, but provides some general guidelines and concepts.
Procedures for Proper Ductwork Sizing for Residential Air Conditioning Systems Ductwork Retrofitting Graphed Blower-Curve-Chart - Opportunity
ROOMDUCT CFM - Formula for finding CFM | DUCT SIZING CHARTS | Use "Manual D" | MAIN DUCT CHART | Square Inches Round Duct | Air Filter Rack Sizing DUCTWORK BASICS Basic AC Overview - Specifications VS. Reality | TEL - Solving for ASP Available Static Pressure | SA - RA | Gurgling@TXV
First & foremost of importance is the correct order of proper procedures to follow for optimal efficiency of operation, & long trouble-free equipment performance.
Before you do anything else, educate yourself enough to ensure that you request the proper things be done in the proper order of sequence.
The first procedure is to do everything possible to reduce all sources of heat-gain & heat-loss.
Then have a manual "J" heat-gain load calc done, followed by a Manual "S" for equipment sizing & then a manual "D" for proper ductwork sizing. All registers, grilles, filter racks, & diffusers must be located & sized for optimal efficient performance of the system.
The correct sizing of residential air conditioning systems & ductwork is crucial to ensuring proper indoor space conditioning, equipment performance, and economical operation. Unfortunately, many A/C contractors measure “correct sizing” by the system's ability to meet any indoor thermostat setting at any outdoor temperature. That method of sizing will lead to inefficient operation for the vast majority of conditioning time. Air conditioning systems “must be sized to meet typical or average indoor and outdoor conditions to ensure proper air mixing, filtration and dehumidification of indoor air across seasonal variations.”
For cooling, size the equipment and system based on 100% of the Total Cooling Load (both sensible and latent loads) at actual outdoor design conditions. Size the duct system properly & make certain that he proper airflow & optimal heatload is passing through the evaporator coil during most of the operating runtime. To Optimize Payback and lower operating costs always do as many things as you can to Reduce the heatgain-heatloss "BEFORE doing the manual J load calc & manual S for sizing the equipment."
To select the “proper size” heating, air conditioning, and duct system for a home, seven factors must be considered and all changes made prior to sizing equipment:
1. Improving Insulation Values and Reducing Infiltration, including e-windows, doors, etc.
2. Reducing Air leakage - air leakage accounts for between 25 percent and 50 percent of the energy used for heating and cooling in a typical older residence.
3. Solar orientation - and ways to reduce the radiant heatload should be considered.
4. The Internal BTU heat generation of appliances and people must be added.
5. Design conditions (typical outdoor and indoor weather conditions, humidity levels, etc.) A scientific calculation (manual J) called a Heat Loss/Heat Gain Calc, tabulates these factors into a load scenario for heating and cooling based on summer & winter outdoor design conditions for the climate where the home is located.
By comparing the heat loss/gain to manufacturer's equipment performance data, a properly sized heating and cooling system is selected. Use indoor design of 75-F dry bulb and 63-F wet bulb, around 50% Relative Humidity.
6. Proper & thorough ductwork testing and design Is Extremely Important for efficiency & BTUH performance - The evaporator coil needs to have an optimal heatload passing through it most of the time in order to approach achieving its Rated BTUH Capacities & its EER & SEER Ratings.
7. For optimal comfort in the Air Conditioning mode diffusers should be at or near the ceiling. Study the diffuser data in respect to room CFM, the required throw & a diffuser Face Velocity of around 500-fpm, & a Terminal Velocity at the human occupant level area of 50 to 75-fpm. This is critical toward achieving an optimal human comfort zone.
What should you expect from the average heating and cooling contractor?
When a typical heating and cooling contractor quotes the efficiency of the equipment (SEER or AFUE) and leads you to believe the new equipment will automatically deliver that efficiency, think again. Typical installed equipment only operates at 55% to 70% of rated capacity.
It is important to understand that equipment ratings are only "the potential efficiency of that component of the system under perfect conditions." "Over half of the system's efficiency depends on the duct system and the field-installation." Check for Return Air drawing Hot Air from attic areas, etc.!
An A/C's system efficiency can often be increased by a skilled tech from 10% to 50%. The biggest benefit is the increase in comfort and lower utility bills!
The heat loss/heat gain calculates the amount of heat transfer by component, based on the surface area, and then tabulates the total transfer for all of the components.
Air leakage/air infiltration: Up to 50% of an average home's heat loss/heat gain is attributable to air leakage/air infiltration. Therefore, determining the proper leakage/air infiltration rate for a specific home is paramount. Design leakage/air infiltration rates are based on dwelling size and projected efficiency or actual measured performance.
Solar orientation, or the amount of window surface area and the direction a home faces can have tremendous impact on the cooling needs (heat gain). Similar houses with different solar orientation will have different cooling loads. Glass facing east/west has more heat gain than glass facing south or North.
The service techs should use a manual D to properly size the ductwork supply air mains and runs to outlet diffusers, as well as the “sizing of the return air ducting in relationship to the btuh/cfm requirements of the various rooms.”
Qualified personnel must perform all installations and services. The duct system sizing and load sizing calculation should follow the design standards of Air Conditioning Contractors of America (ACCA) - Manuals D & J -or the American Society of Heating, Refrigeration & Air Conditioning Engineers, Inc. (ASHRAE) Fundamentals Volume (latest edition).
----------
When sizing ducts, the use of one value throughout will assure incorrect duct size for many branch runout duct segments. If 0.05 is used, nearly half of the runouts of the system will be oversized, resulting in those zones being too cold in summer, resulting in the remaining runouts furthermost from the air handler being undersized, creating zones that are too warm in summer.
The result is a human comfort design failure. The modified equal friction method of Manual D, "requires that the available static pressure from the fan be 'consumed' by the duct through its run from fan to outlet/inlet, with no shortage or excess at the end."
Pressure drop per 100 ft is not an input, it is a calculated intermediate value. A contractor who knows how to do the calculations to determine the available static pressure, and correctly allocate it to the supply runouts and return, is a rare tech.
This page does not explain everything you need to know about proper duct sizing a system for optimal comfort, but provides some general guidelines and concepts.
Wednesday, May 7, 2008
Saving Money on Air Conditioning Repair and Maintenance is not cheap
Experts say you should not cut back when it comes to routine maintenance of your home and vehicle.
Greensboro -- As the cost of filling up your gas tank and grocery cart continues to rise, some families are trying to trim their budgets elsewhere. However, experts say you should not skimp when it comes to routine maintenance of your home and vehicle.
"You should have your air conditioner serviced every spring," explained Scott Loye with Williams Plumbing, Heating and Air. "If you start replacing heating and air conditioning equipment, it can get very expensive. You would be surprised how many calls we run where we prevent big repair bills."
Loye says an annual maintenance contract for heating and air conditioning will cost $150 to $300. He says replacing and air conditioning unit can range from $3,500 to $7,500.
"I think it's well worth it," said Rosemary Prelich, who has her heating and air conditioning systems checked twice a year. "I hear stories of people who don't do anything and when it blows they end up replacing the whole unit."
In addition to your home, experts say you should also budget for routine maintenance on your vehicle. "Oil changes should be performed every 3,000 miles," explained Terry McNeil with Precision Tune Autocare. "Properly inflated tires will help on fuel economy. A clogged air filter will cost 5-10 percent in your fuel economy."
If you follow the maintenance guidelines outlined in your vehicle's user manual, McNeil says your vehicle will run more efficiently and last longer.
"I make sure my car is maintained," said Prelich. "It's better than if something major happens and you're hit with the entire expense at once."
Greensboro -- As the cost of filling up your gas tank and grocery cart continues to rise, some families are trying to trim their budgets elsewhere. However, experts say you should not skimp when it comes to routine maintenance of your home and vehicle.
"You should have your air conditioner serviced every spring," explained Scott Loye with Williams Plumbing, Heating and Air. "If you start replacing heating and air conditioning equipment, it can get very expensive. You would be surprised how many calls we run where we prevent big repair bills."
Loye says an annual maintenance contract for heating and air conditioning will cost $150 to $300. He says replacing and air conditioning unit can range from $3,500 to $7,500.
"I think it's well worth it," said Rosemary Prelich, who has her heating and air conditioning systems checked twice a year. "I hear stories of people who don't do anything and when it blows they end up replacing the whole unit."
In addition to your home, experts say you should also budget for routine maintenance on your vehicle. "Oil changes should be performed every 3,000 miles," explained Terry McNeil with Precision Tune Autocare. "Properly inflated tires will help on fuel economy. A clogged air filter will cost 5-10 percent in your fuel economy."
If you follow the maintenance guidelines outlined in your vehicle's user manual, McNeil says your vehicle will run more efficiently and last longer.
"I make sure my car is maintained," said Prelich. "It's better than if something major happens and you're hit with the entire expense at once."
Monday, May 5, 2008
Troubleshooting Tips
EFFICIENT INDOOR COMFORT - An EXCELLENT SITE for You
FREE HVAC Resources for Professionals
Gurgling sounds at TEV: Low evaporator heat-loads lead to reduced liquid line mass and increased evaporator mass could be due to airflow problems. Eliminate low evaporator heat-loads before looking into adjusting the refrigerant charge.
Gurgling and pulsation noises at the expansion device can be caused by low charge, and/or non-condensibles and moisture in the system. Unbalanced airflow through the various distributor circuits of the evaporator coil will cause the TEV to close down refrigerant flow starving the coil. Piston-flow-rators will make it impossible to properly charge the system and cooling will be greatly compromised unless you eliminate the cause!
On every Rheem condenser cover it lists "non-condensibles and or moisture" as causes for a gurgling or pulsating noise at the expansion device. The entire evaporator circuits, may not become active for various reasons, - "the entire coil must become fully active for efficient performance."
The purpose of these recommendations is to provide liquid refrigerant at the expansion device and provide efficient operation. Hopefully, this will aid your research. If I can be of additional assistance, contact me.
-----------------------------------------------------------
Too many do not properly purge & evacuate contaminated central air conditioning systems.
The Triple Evacuation Method is normally done on central air conditioning systems:
First, remove any valve cores with a special valve core remover this will speed up the evacuation time. Back service valves two turns off their back seat.
1) Re-claim unit charge (Recover all the refrigerant)
2) Charge system to 150 PSIG with dry nitrogen and leak test
3) On contaminated systems replace the filter dryers. Then Repair all leak(s)
4) Evacuate system to 500 microns valve off & see if it holds 500 microns for ten minutes, if it holds, break the vacuum with dry nitrogen
5) Evacuate system to a deeper 300 microns, valve off vac pump, & again break the vacuum with dry nitrogen
6) Evacuate system to 300 microns and charge unit (Recharge with fresh clean refrigerant)
7) Check to see if the Supply and Return air ducts were correctly sized & sealed by the original installer.
Many HVAC contractors will consider this excessive time & effort for contaminated residential air conditioning systems, however it is a must for low temp applications.
The “micron” is a metric unit of measure for distance. The micron is a unit of linear measure; one micron equals 1/25,400ths of an inch. Modern high capacity vacuum pumps help speed up the evacuation process.
===============================================================
DISCLAIMER:
I assume NO responsibility for the USE of any information I post on any of my Web pages,in E-Mails or News Groups.
All HVAC/R work should always be done by a licensed Contractor & properly licensed Techs! This information is only placed on these pages primarily for your understanding & communication with contractors & techs. This information is also for the edification of Contractors and Techs. Never attempt anything that you are NOT competent to do in a SAFE manner! I am NOT liable for your screw-ups, you are liable for what you do! - Darrell Udelhoven
* TXV THERMOSTATIC EXPANSION VALVE APPLICATIONS - Important Info
* SUPERHEAT FIXED ORIFICE - SUBCOOLING TXVs CHARGING PROTOCOL
* Determining Your Air Conditioner's Actual BTUH Capacity Output Surprise!
* SEER RATINGS SEER PAYBACK MISREPRESENTATIONS
* OIL HEATING AIRFLOW TEST
*
AIR-CONDITIONER RUNNING TOO MUCH
3.5-ton system getting less than 1.5-ton of capacity! Low charge - plus
Link below, 3.5-ton to less than 1.5-ton, too! - Way Overcharged - Yes, it happens too often!
* Air Conditioning SEER Levels & Evaporator Air Flow Losing 15 to 40% of SEER Rating?
* Air Conditioning Contractors Discussion Sizing SEER EER Latent Heat
* An Air Conditioning and Heating Efficiency Check Up - Contractor
* Air Conditioning System Sizing for Optimal Efficiency
* Air Conditioning Maximum Efficiency - Check-Up Get your A/C optimized for efficiency
* Air Conditioning - Latent Heat Removal Comfort-Zone Efficiency
* FINDING the LATENT HEAT of CONDENSATION of Your Air Conditioner
Optimizing Room Air Conditioner's EER
* INTRODUCTION TO TOTAL COOLING PERFORMANCE:
Excessive Airflow coupled with an Excessive Charge will greatly reduce AC capacity
How installing a 3-ton system can become a 1.5-ton system of delivered cooling (SURPRISED!)
* NATE - North American Technician Excellence
* New TEC Energy Conservation Testing Technologies
# Air Conditioning Installations Now Produce 95% Failure Rate
Study the Failure Rate Graph - Great Information!
ACH - Air Changes per Hour - AVERAGING INFILTRATION RATES - New
The Honeywell A/C Service Assistant -
SA_Tech_Report.pdf May have promise
FREE HVAC Resources for Professionals
Gurgling sounds at TEV: Low evaporator heat-loads lead to reduced liquid line mass and increased evaporator mass could be due to airflow problems. Eliminate low evaporator heat-loads before looking into adjusting the refrigerant charge.
Gurgling and pulsation noises at the expansion device can be caused by low charge, and/or non-condensibles and moisture in the system. Unbalanced airflow through the various distributor circuits of the evaporator coil will cause the TEV to close down refrigerant flow starving the coil. Piston-flow-rators will make it impossible to properly charge the system and cooling will be greatly compromised unless you eliminate the cause!
On every Rheem condenser cover it lists "non-condensibles and or moisture" as causes for a gurgling or pulsating noise at the expansion device. The entire evaporator circuits, may not become active for various reasons, - "the entire coil must become fully active for efficient performance."
The purpose of these recommendations is to provide liquid refrigerant at the expansion device and provide efficient operation. Hopefully, this will aid your research. If I can be of additional assistance, contact me.
-----------------------------------------------------------
Too many do not properly purge & evacuate contaminated central air conditioning systems.
The Triple Evacuation Method is normally done on central air conditioning systems:
First, remove any valve cores with a special valve core remover this will speed up the evacuation time. Back service valves two turns off their back seat.
1) Re-claim unit charge (Recover all the refrigerant)
2) Charge system to 150 PSIG with dry nitrogen and leak test
3) On contaminated systems replace the filter dryers. Then Repair all leak(s)
4) Evacuate system to 500 microns valve off & see if it holds 500 microns for ten minutes, if it holds, break the vacuum with dry nitrogen
5) Evacuate system to a deeper 300 microns, valve off vac pump, & again break the vacuum with dry nitrogen
6) Evacuate system to 300 microns and charge unit (Recharge with fresh clean refrigerant)
7) Check to see if the Supply and Return air ducts were correctly sized & sealed by the original installer.
Many HVAC contractors will consider this excessive time & effort for contaminated residential air conditioning systems, however it is a must for low temp applications.
The “micron” is a metric unit of measure for distance. The micron is a unit of linear measure; one micron equals 1/25,400ths of an inch. Modern high capacity vacuum pumps help speed up the evacuation process.
===============================================================
DISCLAIMER:
I assume NO responsibility for the USE of any information I post on any of my Web pages,in E-Mails or News Groups.
All HVAC/R work should always be done by a licensed Contractor & properly licensed Techs! This information is only placed on these pages primarily for your understanding & communication with contractors & techs. This information is also for the edification of Contractors and Techs. Never attempt anything that you are NOT competent to do in a SAFE manner! I am NOT liable for your screw-ups, you are liable for what you do! - Darrell Udelhoven
* TXV THERMOSTATIC EXPANSION VALVE APPLICATIONS - Important Info
* SUPERHEAT FIXED ORIFICE - SUBCOOLING TXVs CHARGING PROTOCOL
* Determining Your Air Conditioner's Actual BTUH Capacity Output Surprise!
* SEER RATINGS SEER PAYBACK MISREPRESENTATIONS
* OIL HEATING AIRFLOW TEST
*
AIR-CONDITIONER RUNNING TOO MUCH
3.5-ton system getting less than 1.5-ton of capacity! Low charge - plus
Link below, 3.5-ton to less than 1.5-ton, too! - Way Overcharged - Yes, it happens too often!
* Air Conditioning SEER Levels & Evaporator Air Flow Losing 15 to 40% of SEER Rating?
* Air Conditioning Contractors Discussion Sizing SEER EER Latent Heat
* An Air Conditioning and Heating Efficiency Check Up - Contractor
* Air Conditioning System Sizing for Optimal Efficiency
* Air Conditioning Maximum Efficiency - Check-Up Get your A/C optimized for efficiency
* Air Conditioning - Latent Heat Removal Comfort-Zone Efficiency
* FINDING the LATENT HEAT of CONDENSATION of Your Air Conditioner
Optimizing Room Air Conditioner's EER
* INTRODUCTION TO TOTAL COOLING PERFORMANCE:
Excessive Airflow coupled with an Excessive Charge will greatly reduce AC capacity
How installing a 3-ton system can become a 1.5-ton system of delivered cooling (SURPRISED!)
* NATE - North American Technician Excellence
* New TEC Energy Conservation Testing Technologies
# Air Conditioning Installations Now Produce 95% Failure Rate
Study the Failure Rate Graph - Great Information!
ACH - Air Changes per Hour - AVERAGING INFILTRATION RATES - New
The Honeywell A/C Service Assistant -
SA_Tech_Report.pdf May have promise
Sunday, May 4, 2008
Green building takes off
dc pro launches green buildings division
Re-affirming its commitment to sustainable and eco-friendly practices in developing green buildings, DC PRO Engineering announced the formal launch of its Green Buildings division at the three day Climate Control Conference (C3) which was held in Dubai from the 28th till the 30th of April, 2008.
DC PRO Engineering is a leading electro mechanical consultancy firm specializing in District Energy services and Green Buildings MEP services in the Middle East. The Green buildings services division which has been operational since 2007 has grown in terms of human resources strength and service offerings that cater to the demand for property infrastructure that provides for improved air and water quality, reduced consumption of energy and conservation of natural resources.
Click Here!
DC PRO is a member of US Green Building council (USGBC) and has one LEED certified Engineer and many more in the process of getting certified.
Commenting on the launch, Mr. George Berbari, CEO, DC PRO Engineering said, “Increasingly, it is seen that sustainability, environment –friendly and ‘go green’ concepts figure in the top agenda of the property developers in the region. DC PRO sees immense potential in the market for products and services that address these challenges and this is exactly why we chose to establish a business unit with specific focus on Green Buildings MEP designing and services”.
“The Green Buildings division will play a significant role in the future growth plans of the company and will help us to keep up with the momentum in the construction industry in the region which is moving towards greener and smarter buildings”, added Mr. Berbari.
DC PRO engineering provides building services to clients in the fields of HVAC, Plumbing and electrical systems for all kinds of projects through the Green Buildings division. Their innovative Green Building design technique and services incorporate measures that best promote energy efficiency.
For instance, clients save 70% of fresh air energy, 30% of air side fan energy, 50% of lighting energy, 90% of hot water energy and 30% of water usage. The green building consulting division also recommends and implements solutions which improve Indoor Air Quality (IAQ) and provide a healthier and comfortable environment for increased occupant productivity. DC PRO projects with thrust on conservation of natural energy sources, gives its customers access to the benefits of day light harvesting and use highly efficient lighting systems to save on operating energy.
The Business Boulevard located in Sheikh Zayed Road in Dubai is one of DC PRO Green Building division’s high-profile projects in the region. DC PRO is currently designing jointly with Pierre Dammous & Partners, the MEP for the Business Boulevard which constitutes of 700,000 m2 build up area and comprises of a common podium, three residential towers, Hotel, furnished apartment building and three office towers. DC PRO has completed for M/s Rakeen, the leading Ras Al Khaima Real estate Developer, the Green Building code inclusive of connection requirements for highly efficient district cooling system for all of its developments.
DC PRO which supplies district cooling engineering services to several prominent clusters in the region has now achieved a total design schemes with total capacity of 600, 000 tones and has close to 500,000 tones in the pipeline.
As an active participant at the C3 conference, DC PRO participated in a panel discussion for fresh air energy conservation and presented a paper on 'Seeking Clarity on what the Government of Dubai expects of builders, consultants, contractors and clients in implementing Green Building projects’.
About DC PRO Engineering
DC PRO Engineering is a recognized leading world engineering authority in the field of district cooling and is capitalizing on its leadership in the air conditioning field to extend its services to provide a world class Green Buildings’ services.
Re-affirming its commitment to sustainable and eco-friendly practices in developing green buildings, DC PRO Engineering announced the formal launch of its Green Buildings division at the three day Climate Control Conference (C3) which was held in Dubai from the 28th till the 30th of April, 2008.
DC PRO Engineering is a leading electro mechanical consultancy firm specializing in District Energy services and Green Buildings MEP services in the Middle East. The Green buildings services division which has been operational since 2007 has grown in terms of human resources strength and service offerings that cater to the demand for property infrastructure that provides for improved air and water quality, reduced consumption of energy and conservation of natural resources.
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DC PRO is a member of US Green Building council (USGBC) and has one LEED certified Engineer and many more in the process of getting certified.
Commenting on the launch, Mr. George Berbari, CEO, DC PRO Engineering said, “Increasingly, it is seen that sustainability, environment –friendly and ‘go green’ concepts figure in the top agenda of the property developers in the region. DC PRO sees immense potential in the market for products and services that address these challenges and this is exactly why we chose to establish a business unit with specific focus on Green Buildings MEP designing and services”.
“The Green Buildings division will play a significant role in the future growth plans of the company and will help us to keep up with the momentum in the construction industry in the region which is moving towards greener and smarter buildings”, added Mr. Berbari.
DC PRO engineering provides building services to clients in the fields of HVAC, Plumbing and electrical systems for all kinds of projects through the Green Buildings division. Their innovative Green Building design technique and services incorporate measures that best promote energy efficiency.
For instance, clients save 70% of fresh air energy, 30% of air side fan energy, 50% of lighting energy, 90% of hot water energy and 30% of water usage. The green building consulting division also recommends and implements solutions which improve Indoor Air Quality (IAQ) and provide a healthier and comfortable environment for increased occupant productivity. DC PRO projects with thrust on conservation of natural energy sources, gives its customers access to the benefits of day light harvesting and use highly efficient lighting systems to save on operating energy.
The Business Boulevard located in Sheikh Zayed Road in Dubai is one of DC PRO Green Building division’s high-profile projects in the region. DC PRO is currently designing jointly with Pierre Dammous & Partners, the MEP for the Business Boulevard which constitutes of 700,000 m2 build up area and comprises of a common podium, three residential towers, Hotel, furnished apartment building and three office towers. DC PRO has completed for M/s Rakeen, the leading Ras Al Khaima Real estate Developer, the Green Building code inclusive of connection requirements for highly efficient district cooling system for all of its developments.
DC PRO which supplies district cooling engineering services to several prominent clusters in the region has now achieved a total design schemes with total capacity of 600, 000 tones and has close to 500,000 tones in the pipeline.
As an active participant at the C3 conference, DC PRO participated in a panel discussion for fresh air energy conservation and presented a paper on 'Seeking Clarity on what the Government of Dubai expects of builders, consultants, contractors and clients in implementing Green Building projects’.
About DC PRO Engineering
DC PRO Engineering is a recognized leading world engineering authority in the field of district cooling and is capitalizing on its leadership in the air conditioning field to extend its services to provide a world class Green Buildings’ services.
Saturday, May 3, 2008
Go Green and save at the same time
Make Your House Energy Efficient And Save Money
As we know 17 per cent of all energy used goes toward running our homes. Consequently, the potential for substantial energy savings is high, provided homeowners take the necessary steps. The benefits apply particularly to older homes is higher then new homes.
Here are few tips which can save to hundreds of dollars:
- Compact fluorescent light bulbs use one-quarter of the energy of standard incandescent bulbs, so a 15-watt CFL produces the same amount of light as a 60-watt incandescent bulb. CFLs certified by Energy Star, an international marketing symbol to identify energy-saving home products, are more expensive than incandescent bulbs, but last longer.
With an average 30 light fixtures in each of countries 12 million households, replacing a single 60-watt incandescent bulb with a 15-watt CFL in each one could save up to $73 million a year in energy costs.
- Energy Star appliances make a big difference to the efficiency of your home. Refrigerators certified under the program must be at least 15 per cent more efficient than federal minimum energy-performance standards, which they typically achieve by using a more energy-efficient compressor and better insulation than conventional models. Energy Star standard-size freezers must exceed minimum energy performance standards by at least 10 per cent, while compact models must beat them by at least 20 per cent.
Qualified dishwashers must outperform the standard by at least 25 per cent.
Many use "smart" sensors that adjust the wash cycle and amount of water to match the load, and may also have an internal heater.
- About 15 per cent of a typical household energy bill goes to heating water.
The water-heater is one of the biggest energy consumers in many homes, second only to the furnace. If you've got an older hot-water appliance, you can save by insulating the heater itself, the first three metres on cold-water pipes and the first two meters on hot water pipes. Also, many water-heater manufacturers set the temperature of the tank to 60 C (140 F), which you can reduce to as low as 55 C (130 F).
- Look for ways to reduce your water use. A low-flow shower head can cut your water use in the shower by over 30 per cent, and installing tap aerators can give you the same pressure with less water flow.
You can reduce the energy you use for a load of laundry by 93 per cent by washing and rinsing your clothes in cold water. You can also reduce water use by installing a low-flow toilet.
- Older houses can usually benefit from retrofitting to keep the heat in.
Adding R-40 insulation, caulking, weatherstripping, improving windows and doors can all save money and energy. Poorly insulated attics are a good candidate for improvement; if yours has less than 15 centimeters (six inches) of insulation, it is worth putting more in.
Insulating basements will also cut heat loss.
As we know 17 per cent of all energy used goes toward running our homes. Consequently, the potential for substantial energy savings is high, provided homeowners take the necessary steps. The benefits apply particularly to older homes is higher then new homes.
Here are few tips which can save to hundreds of dollars:
- Compact fluorescent light bulbs use one-quarter of the energy of standard incandescent bulbs, so a 15-watt CFL produces the same amount of light as a 60-watt incandescent bulb. CFLs certified by Energy Star, an international marketing symbol to identify energy-saving home products, are more expensive than incandescent bulbs, but last longer.
With an average 30 light fixtures in each of countries 12 million households, replacing a single 60-watt incandescent bulb with a 15-watt CFL in each one could save up to $73 million a year in energy costs.
- Energy Star appliances make a big difference to the efficiency of your home. Refrigerators certified under the program must be at least 15 per cent more efficient than federal minimum energy-performance standards, which they typically achieve by using a more energy-efficient compressor and better insulation than conventional models. Energy Star standard-size freezers must exceed minimum energy performance standards by at least 10 per cent, while compact models must beat them by at least 20 per cent.
Qualified dishwashers must outperform the standard by at least 25 per cent.
Many use "smart" sensors that adjust the wash cycle and amount of water to match the load, and may also have an internal heater.
- About 15 per cent of a typical household energy bill goes to heating water.
The water-heater is one of the biggest energy consumers in many homes, second only to the furnace. If you've got an older hot-water appliance, you can save by insulating the heater itself, the first three metres on cold-water pipes and the first two meters on hot water pipes. Also, many water-heater manufacturers set the temperature of the tank to 60 C (140 F), which you can reduce to as low as 55 C (130 F).
- Look for ways to reduce your water use. A low-flow shower head can cut your water use in the shower by over 30 per cent, and installing tap aerators can give you the same pressure with less water flow.
You can reduce the energy you use for a load of laundry by 93 per cent by washing and rinsing your clothes in cold water. You can also reduce water use by installing a low-flow toilet.
- Older houses can usually benefit from retrofitting to keep the heat in.
Adding R-40 insulation, caulking, weatherstripping, improving windows and doors can all save money and energy. Poorly insulated attics are a good candidate for improvement; if yours has less than 15 centimeters (six inches) of insulation, it is worth putting more in.
Insulating basements will also cut heat loss.
Friday, May 2, 2008
Air Conditioning Cleaning
CONDENSATE TRAY CLEANING - Cleaning suggestions for A/C System Condensate Systems
Should we disinfect cooling system equipment or condensate trays?
Should we be putting bromide or chlorine tablets in our condensate trays to keep bacteria from growing?
If we should be, then do we need to alternate bromide with chlorine on some type of frequency to prevent development of resistant bacteria?
We're discussing condensate trays from mechanical equipment like heat pumps, fan coil units and air handlers with AC coils.
These pieces of equipment have condensate trays which are then drained through a small pipe, usually clear, but not always, with a trap in it, to a drain.
These condensate trays have some standing water in them when the AC is functioning. Should these condensate trays be treated with an algaecide of some sort?
There are risks beyond mold and algae, in particular Legionella bacteria (legionnaire's disease) which can have an alarmingly high mortality rate, and also potential hazard sources such as biofilms that can include other bacterial and maybe other pathogens. However the risk of formation of problem levels of mold, bacteria, or other pathogen is probably not the same across all buildings nor types of equipment, and much of the risk may depend on installation and maintenance details at individual installations.
Particularly in climates with a high humidity and a heavy cooling load, and depending on details of the design and installation of the air handler unit and duct work, there is risk of blowing pathogen-contaminated water droplets downstream inside the air conditioning duct work and thus exposing building occupants. With rooftop-mounted cooling units such as cooling towers using water, conditions may be still more attractive for growth of pathogens and there is some risk of movement of pathogens out of the cooling equipment to people located nearby and downwind from the equipment, even if they are outside the building which the equipment actually serves.
Should we disinfect cooling system equipment or condensate trays?
Should we be putting bromide or chlorine tablets in our condensate trays to keep bacteria from growing?
If we should be, then do we need to alternate bromide with chlorine on some type of frequency to prevent development of resistant bacteria?
We're discussing condensate trays from mechanical equipment like heat pumps, fan coil units and air handlers with AC coils.
These pieces of equipment have condensate trays which are then drained through a small pipe, usually clear, but not always, with a trap in it, to a drain.
These condensate trays have some standing water in them when the AC is functioning. Should these condensate trays be treated with an algaecide of some sort?
There are risks beyond mold and algae, in particular Legionella bacteria (legionnaire's disease) which can have an alarmingly high mortality rate, and also potential hazard sources such as biofilms that can include other bacterial and maybe other pathogens. However the risk of formation of problem levels of mold, bacteria, or other pathogen is probably not the same across all buildings nor types of equipment, and much of the risk may depend on installation and maintenance details at individual installations.
Particularly in climates with a high humidity and a heavy cooling load, and depending on details of the design and installation of the air handler unit and duct work, there is risk of blowing pathogen-contaminated water droplets downstream inside the air conditioning duct work and thus exposing building occupants. With rooftop-mounted cooling units such as cooling towers using water, conditions may be still more attractive for growth of pathogens and there is some risk of movement of pathogens out of the cooling equipment to people located nearby and downwind from the equipment, even if they are outside the building which the equipment actually serves.
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