When should a drain trap be installed on a split air conditioning system?

A drain trap should be installed on a split air conditioning system when the air handler drain is located on the negative air side. This is crucial for preventing backflow, which can lead to water damage and other issues within the system. In a split system, the air handler typically creates a negative pressure environment, which can draw water back into the unit if there is no proper trap installed. The trap acts as a barrier, allowing condensate to drain away while preventing air from re-entering the system.

Proper installation of the drain trap not only protects the integrity of the air conditioning system but also ensures that moisture does not accumulate where it could lead to mold growth or damage to the surrounding structural components. Thus, understanding the relationship between air pressure conditions and drainage is essential for effective HVAC system maintenance and operation.