Replacing a Heat Pump Condenser Contactor

Three weeks ago, I had never even heard of a “heat pump condenser contactor”, and now here I am writing a post about it!

What happened three weeks ago? Well, my husband came home to find that the temperature downstairs in our house was around 80 degrees. He went to turn the heat down, and found that the thermostat was set to 62, as it usually is during the day. He turned the heat completely off through the thermostat, but it still continued to run. So he shut off the power to the downstairs heat at the panel by flipping the breaker.

When I got home that night, he told me about the problem. My first thought was that the thermostat had become faulty. I had replaced the old mercury thermostat with a digital, programmable one not long after we bought the house, around ten years ago. I figured that, like most electronics, it had a limited life-span and was simply dying. So the first thing that I did was replace the thermostat with a wonderful new Honeywell digital, programmable thermostat, which cost around $80 at Home Depot. We had already installed this thermostat for our upstairs unit, and loved it. (By the way, I highly recommend programmable thermostats. They save so much energy, not to mention the effort of changing the temperature before you leave or when you get home. The one that we purchased is currently marked down on Amazon – check the “Home and Garden” section of my Amazon store on the Recommendations tab above, if you are interested.)

With the new thermostat installed, we turned the breaker back on and tested the heat pump. Unfortunately, the heat continued to run even after the thermostat had cycled it off. (When the thermostat reaches the set point, there is an audible click when it cycles off.) So I pulled out the laptop, and Googled something along the lines of “heat pump won’t turn off”. After about 30 minutes of reading, it sounded like the most common cause for this problem is the “contactor” unit on the “condenser” getting frozen on, either from failure or from debris on the unit. Most of the posts indicated that this was a fairly simple repair, for someone comfortable with electrical work.

At this point, I think it is important to say this:

Disclaimer: I am not a contractor, electrician, or heating and cooling professional. The following information is based on internet sources and my own experience. If you are not comfortable with electrical repair, I recommend that you call a professional for repair.

I decided that I might try to attempt this repair myself. I had learned from my research that the condenser unit is that part outside with the fan in it (aren’t I scientific and technical sounding? Hence the above disclaimer.) First, I located the manufacturer (Goodman) and serial number (CPLE18-1A) of our heat pump condenser unit. We have two units, so I turned the upstairs one on, so I could make sure I was looking at the right one. Then, I did an internet search for “Goodman heat pump CPLE18-1A contactor”. That brought me to Repair Clinic, a site which I have been to multiple times looking for washer and dryer parts. I searched their site for the part number that I needed. Though Repair Clinic sells the parts as well, I ordered the part from Amazon, so that I could use my Amazon credit card.

The part arrived within a couple days, however, we couldn’t install it right away since we need daylight to work. In the meantime, we kept using the breaker to turn the heat pump on and off (I would not recommend this, by the way, and you will see why shortly). One night, however, I went to turn the breaker on, and found that even with the breaker on, the heat pump did not turn on. The breaker is a 30 amp double pole breaker. Every time we would try to cycle it back on, one side seemed to require extra pushing to get it to snap into place. My husband had also reported that the day the heat was stuck on, the breaker itself was very warm when he went to turn it off. Interesting …

Finally, Saturday arrived and we could install the new part. The first thing that I did was shut off all the power, and I mean all the power. I turned each breaker in the box off one at a time, then turned off the main. There is also a subpanel on the outside near the condenser units, and I turned those breakers off as well.

Next, we removed the screws that held the top of the unit in place, as seen in the photo above. With the top off, we looked inside and saw nothing that looked even remotely like the part we had in our hand. Then we noticed that there was another panel on the back corner of the unit. We removed that and voila! There was the contactor and about 1400 wires.

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(Lesson learned: we did not need to take the top of the unit at all to access the panel for the unit. Still, it gave us a chance to clean out all the abandoned spider nests – shudder!)

There were multiple colored wires coming in and out of the contactor. I carefully took pictures of the connections from as many angles as I could to document which wire went where. Then, I carefully removed each wire from the contactor. As I removed the wires, I inspected their condition. They all looked to be in good shape, except for one that had a tiny bit of exposed wire at the connector, which I covered with a small piece of electrical tape, just to be safe.

Next, I removed the three screws that held the contactor in place, and removed it. I then connected the wires to the new contactor in the same places that they had been before. I was very glad that I had pictures at this point! On the right side of the contactor, I connected the blue wire to the white wire, then connected it and the black wire to the contactor. You can see the exposed wire on the white wire – these are the pictures of the connections to the old part. I taped over that wire to be safe.

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On the left side of the contactor, I connected the yellow and gold wires.

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On the top of the contactor, I connected the black straight and L-shaped wires and the orange straight and L-shaped wires.

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And on the bottom of the contactor, I connected the incoming black (gray) and white wires from the power source.

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I checked all the connections to make sure that they were snug. Then I connected the contactor to the unit using the screws that I had removed from the old part. See? All wired back up and ready for use!

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We looked at the old contactor part, and with a little manipulation we were able to unstick the plunger that allows it to switch on and off. We saved it, just in case, though I think it was probably due for replacement if it had begun to have this problem.

We replaced the back panel and the top. I then went back inside and turned the main power back on. Then I slowly turned the individual breakers on one by one, including the one for the heat pump. I then went outside to the subpanel and turned the two breakers back on. Then back inside to the thermostat, where I turned the heat on. It was 75 degrees yesterday so I had to run the thermostat way up to get it to kick in. I heard the thermostat click, but the heat did not come on (insert expletives and frustrating ranting here).

I turned off all the power again, one breaker at a time and then the main. We removed the back panel and checked all the connections. We left the panel off, then I turn everything back on. I took my multi-meter and checked the black and white wires coming into the unit. No power.

So there was no power getting to the unit. Hmmm … At this point, we decided to replace the circuit breaker. I went to the Home Depot website to make sure that they had the right type of breaker for our load center (you have to match the break to the panel, you can’t just use any old breaker). Then I Googled “how to replace a circuit breaker” and found a video. Looks pretty easy! My husband and I drove to Home Depot for the replacement breaker and a non-contact voltage tester, and then to Panda Express.

Today, I will replace the circuit breaker. You will know that I did not electrocute myself if you see a post about that process! Hopefully, that will fix our issues. If not, it will be time to call the professionals. Still, even if it comes to that, I am glad we tried these fixes first. They are inexpensive and we learned quite a bit about our home in the process.

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