Thorough Heat Pump Repair in Johnson City, TN Gave Our New Customer Some Cooling Again

We received a call from a new customer in Johnson City, TN that was in need of a heat pump repair. She stated that their old Payne heat pump was not working. There was no air coming out of the vents and the outdoor unit wasn’t turning on either. We advised her to turn the thermostat to the off position.

When we arrived, we pulled the thermostat off the wall and we did not have any low voltage at the thermostat between R & C. The customer had a display on the thermostat because she had battery back-up which was allowing the display to light up even without low voltage present. We went under the home and the indoor unit did not have any water protection devices so we knew that we didn’t have a float switch or wet switch tripped.

We opened the indoor unit and the low voltage fuse had blown on the indoor control board. We put a low voltage tool into the fuse holder to close the R circuit on the low voltage control and restored high voltage to the system. The low voltage tool immediately tripped. We began searching the low voltage circuits for a short to ground with our low voltage tool protecting the circuit board. We had to separate all of the low voltage control wires to the indoor unit, outdoor unit, and the thermostat and test each circuit individually with our Short Pro tool. We identified the Y circuit to the outdoor unit as the cause for our low voltage short to ground on the HVAC unit.

We checked the Y circuit at the air handler under the home that came in from our outdoor heat pump to see if we had any knicks or cuts in the wire. We traced the thermostat wire through the crawl space and did not find anything either. We went outside and shut high voltage off to the outdoor unit and opened the service cabinet. We tested the high voltage contactor coil because they are known to be problematic if the resistance gets too low on them and the coil tested in range. We checked the thermostat wire outside for any knicks or cuts as well and it was ok. We traced the Y circuit in the service cabinet and did not find any issues either. We popped the top off the outdoor heat pump and started tracing the Y circuit wires inside the outdoor heat pump that was exposed to the weather. We found 2 spots where the Y circuit could be shorting to ground.

The first place was where the Y circuit entered into the service cabinet in a bundle of wires. The wire had rubbed through and was touching bare wire to the cabinet. We repaired the wire at that point to prevent the wire from shorting to the cabinet. We continued looking through the Y circuit and found another point where the Y circuit had rubbed through on a wire from a pressure switch. One of the pressure switch wires that was tied into the Y circuit had rubbed through on a copper refrigerant line and was shorting to ground. We repaired that wire as well and did some preventative measures inside the outdoor unit with Armaflex insulation, UV resistant tape, UV resistant zip ties, and UV resistant flexible conduit.

After completing the preventative measures and fixing the 2 spots on the Y circuit inside the outdoor heat pump we put the outdoor unit back together. We went back under the home and our low voltage test tool was no longer showing a short to ground on the Y circuit to the outside unit. We connected our low voltage wires back into the circuit and placed a low voltage fuse into the fuse holder. We restored high voltage power to the HVAC unit and called for cooling on the thermostat. The HVAC unit fired up and began cooling the home again. We performed a temperature split test and the heat pump was falling into range of what would be expected. We offered additional services on the unit since it had been a long time since anyone had checked it out and the customer declined since the unit was cooling good again. They didn’t want to spend anymore money on a 20+ year old system.

If you reside within our service area of Northeast Tennessee and are in need of a heat pump repair even on an older unit, please feel free to contact us. We like helping our customers out and don’t have a problem with keeping old units running. Stay safe and best wishes.

Location: Johnson City, TN