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.