One of the most common furnace problems that I see is when the furnace hot surface ignitor will not glow. The furnace may have a bad ignitor, loose wire connections, open limit switch, open rollout switch, open pressure switch, or bad control board. This is what you might see in the furnace sequence of operation.
Bob and Tim have gotten together for another informational session. Tim requested some extra after-hours training about heat pumps. In their last session, they talked about heat pump mechanical problems. This time they discuss electrical problems.
In this month’s troubleshooting problem, we have a customer who can only tell us that the equipment that serves their small office “isn’t working.” When you arrive, you confirm that the building temperature is far from the thermostat set point even though the indoor fan motor is operating normally and the return air filter is clean.
Bob and Tim were taking a break and Bob began explaining some of the tips that he has learned in servicing heat pumps. Bob said, “Let’s go over some of the service problems that you may have with a heat pump.”
The season was getting colder and heating calls were beginning to come in. Bob and Tim were riding to a large residence that had three heat pumps to provide heating and cooling for the structure and Tim asked a question, “Why are heat pumps so popular?”
Our troubleshooting problem involves a split system heat pump in which the outdoor unit is operating in an 85°F ambient, and when you arrive in response to the customer’s no cooling complaint, you find the indoor fan operating normally, and you also note that 240 volts is read at L1 and L2 of the outdoor unit.
Bob and Tim were doing a routine service contract call. They had fastened gauges to the compressor at the condensing unit and had a temperature lead fastened to the suction line at the evaporator coil. They were observing the pressures and temperatures and Tim said, “The suction pressure is not stable. Isn’t it supposed to be stable during a long running cycle?”