5 Year Old AC Unit Gets Brought Back to Life with an AC Repair in Johnson City, TN

Received a call from a new customer in Johnson City, TN in need of an AC repair on their 5 1/2 year old AC servicing the first floor of their home. He stated that the indoor blower motor was moving air, but the outdoor unit was not turning on.

When we arrived, we opened the electrical panel to the first floor outdoor unit and we only had 30 volts entering the outdoor unit at the high voltage contactor. We traced the voltage back to the service disconnect and we had 245 volts at the service disconnect. We tested the fuses at the service disconnect and one fuse was good, but the other fuse had no continuity so it was testing bad.

We tested the dual run capacitor on the AC unit and the capacitor tested in range. We opened the outdoor AC top and pulled the compressor plug. We tested the compressor to ground and the compressor was not grounded. We checked the ohms of the windings on the compressor and they tested within range. We inspected the compressor plug and it looked ok as well. We tested the outdoor fan motor to ground and it was not grounded. We checked the high voltage wires inside the AC to see if we had any high voltage wires shorting to ground and everything looked ok with the wiring.

We put the unit top back together and replaced the fuses with a new pair. We greased the fuses and disconnect pullout with di-electric grease. We restored power to the outdoor unit and now we had high voltage at the high voltage contactor. We performed an inrush amp reading on the compressor at startup and the compressor was drawing 102 amps at startup, which was close to the LRA rating of the compressor of 109 amps. We took amp draws on the outdoor fan motor and the compressor while the unit was running as well.

We suggested a soft start device for the AC unit as the best option to help dramatically lower the inrush amps at startup on the compressor which would help prevent the fuses from failing again. Soft start devices are more expensive, but they are a better option than a traditional 2 wire hard start device or a hard start with an external relay. We also gave the customer an option for a KS-1 Kick Start device with an external relay as a cheaper alternative to the soft start device and a traditional hard start without an external relay. A good, better, best option. The KS-1 Kick Start devices are cheaper than a soft start, less labor intensive to install, and they are a better option than a standard hard start device that doesn't utilize an external relay. A traditional hard start device without an external relay can have a hard time keeping up with cycle rates on hot days, but can typically get the job done and they are the cheapest option.

The customer chose the middle option which was the KS-1 Kick Start with an external relay. We grabbed a KS-1 from the van and installed it on the AC unit. We restored power to the AC unit and fired it up again while taking another inrush amp reading. The AC unit's compressor only drew 17.6 amps at startup instead of drawing 102 amps. The KS-1 Kick Start device reduced the inrush amps by 84.4 amps at startup which is quite considerable. We monitored the system's performance, cleaned up our tools, and were able to get the unit back up and cooling.

If you are inside of our service area of Northeast Tennessee and are in need of an AC repair, please feel free to reach out to Magnolia Services based out of Johnson City, TN. We would be happy to assist you with your HVAC needs. Stay safe and best wishes.

Location: Johnson City, TN