Tightening a home’s envelope may reduce the air supply needed for combustion, and when there’s not enough combustion air, equipment could have combustion ventilation problems. Thus, the people who sealed up homes (often referred to as the weatherization industry) needed a way to determine if sealing a home up would undermine the safe operation of combustion equipment. To meet this safety need, they embraced combustion appliance zone (CAZ) depressurization testing.
The ASRAC established the Central Air Conditioners and Heat Pumps Working Group in July 2015; it is the latest of several working groups to successfully create negotiated efficiency standards for industry equipment. Other negotiated rulemakings aided by working groups include walk-in coolers and freezers, regional standards enforcement, and commercial rooftop air conditioners and furnaces.
In this troubleshooting situation, you are responding to a customer’s complaint about their heat pump, and you’re not the first technician called in to solve this problem of “not keeping the home comfortable and running a lot.”
Bob and Tim were at a retail store and were preparing to do a routine service call on a 5-ton heat pump. It was a fall day with a temperature of about 50°F when they turned the heat pump on. After doing a visual inspection at the air handler, they moved to the roof to give the outdoor unit a visual inspection.