Plumbing

What Is the Connection Between Plumbing and HVAC?

The connection between plumbing and your HVAC system may not seem obvious at first. Though your household pipes don’t generate heating or cooling, your HVAC components do produce water — sometimes a lot of it — that requires plumbing to drain it all away properly. 

Two parts of the cooling and/or heating system need plumbing connections to convey water out of the house:

  • Central AC. Humidity reduction is an essential part of the cooling process in a central air conditioner. The indoor evaporator coil in the AC can condense many gallons of condensate water every day during operation in hot, humid summer conditions. This condensate drips down into a collection pan beneath the indoor air handler, then flows through a pipe connected to the household drain system.

  • High-efficiency furnace. Unlike standard-efficiency furnaces, high-efficiency models incorporate a secondary heat exchanger that extracts extra heat by condensing water vapor that's present in the furnace exhaust airflow. This water collects in a plastic reservoir, then is taken by gravity through a sloped drain tube and is discharged outside the house.

What Can Go Wrong?

A clogged central AC drain pipe, often a result of algae or mold growth inside the condensate collection pan, will rapidly overflow every time the air conditioner cycles on. Because the location of the pan is beneath the air handler, occupants of the house may not notice the ongoing overflow before substantial water damage to the floor and adjoining area has occurred.

A high-efficiency furnace has a safety sensor that detects clogs in the water drain tube. If drainage stops, the sensor will automatically shut down the unit. Heating function cannot be restarted until the clog issue is resolved by an HVAC service technician. 

Prevention Is Preferable

Annual preventative maintenance by a qualified HVAC contractor includes addressing plumbing issues that may affect heating and cooling systems. The service includes an inspection and cleaning to support proper function of both the AC condensate pan and drain pipe, as well as the high-efficiency furnace drain system.

For professional service to prevent or repair plumbing issues associated with your HVAC system, contact Air Assurance.