Home Repair 101: Replacing a Thermostat

Not nearly as difficult as I expected it to be.

In hindsight, I should have realized that the upstairs thermostat was on its way out. What else could explain the way it cycled on and off so frequently? But I didn’t really think about it. Sure, it was annoying, but it wasn’t my problem.

Until it became my problem.

Thermostat
The programmable thermostat in my bedroom. Setting it to 72° in a 65° room should have triggered it to go on.

I turned the heat down to 60°F in both zones when I went to Parker on Friday afternoon. I’d be gone overnight and couldn’t see heating the house while I was away. But when I got home on Saturday and turned the heat back up to 70°, only the downstairs heat pump turned on. Upstairs remained stubbornly off, despite the fact the room temperature was a chilly 65 in the afternoon sun.

I tried the on/off switch. No joy. I tried switching the Fan from Auto to Manual. The fan came on but it soon became apparent that it wasn’t blowing heat. I flicked the Electric Heat switch on the side (not visible in the photo) that I’m pretty sure kicks in some sort of electric heating element. Still no heat.

Clearly, something was broken. Was it the thermostat or the heat pump?

Logic says to repair/replace the cheapest thing first. So as I put an extra blanket on the bed that night, I planned to replace the thermostat the next day.

In the morning, the bedroom was 59°F. It was tough getting out of my cozy bed. Meanwhile, the heat downstairs was working overtime, sending warm air up while the cool air dropped down. I figured that if I couldn’t get the heat going that day, I’d get a fire going to help warm the house. (I still have quite a bit of firewood to burn.)

I took Penny with me to Wickenburg Airport for the Sunday morning coffee and donuts gathering. I’d started the ritual back when I managed the fuel concession at the airport in 2002-2004 and was very happy to see that more than 10 years later others were carrying on the tradition for me. It was great to meet up and chat with the other pilots.

I pulled Jason aside and queried him on the thermostat replacement. He assured me that I’d have no trouble doing it. He recommended that I take a photo of the wiring setup before pulling everything apart — just in case I had to put it all together again.

After picking up my toolbox from my hangar, Penny and I went to the hardware store. They didn’t offer many options. I wasn’t interested in making a big investment in this home repair since I didn’t expect to be living in the house much longer. But I did want a unit that was compatible with my system. A Honeywell device looked about right at $35, so I bought it.

I should mention here that several of my Twitter and Facebook friends were following my dilemma and were recommending that I buy a Nest thermostat. I’d heard all kinds of good things about Nest and really wanted one. But I certainly was not going to buy a $250 thermostat for a house I hoped to be out of by June. Instead, I’d buy one for my new home when it was built. Besides, I needed a solution quickly and I wouldn’t be able to get my hands on anything as nice as a Nest in Wickenburg. And there was always the chance that the problem wasn’t the thermostat at all — it could be the 15-year-old heat pump unit.

Inside the old Thermostat
Inside the old thermostat were cobwebs and a tangle of wires.

I went home, made myself a cup of hot cocoa, and got to work. The instructions that came with the Honeywell unit were extremely easy to follow, with a full page in the little booklet for every step. I discovered when I removed the main plate for the thermostat that the wires were not color-coded but letter-coded: each wire went into a different lettered slot. There were also two jumper wires. And, of course, the switch that had been added for the electric heat. The Honeywell unit had come with a little sheet full of lettered stickers. The instructions said to label each wire as I removed it. So that’s what I did. I found that I also had to customize one of the labels for one of the jumper wires since one letter was used twice.

The Wires
I admit that I began to have doubts about my ability to complete this little project when I was faced with this mess.

That done, I removed the back plate of the old thermostat, leaving the wires hanging out of the wall.

I should mention here that the Honeywell unit had no way to hook up that little switch. The old thermostat had been cut and customized to accommodate it. I was not prepared to do that. Or interested in taking the extra effort to try. This was a temporary fix that might not even work. So I decided to ignore it — except for the one labeled wire that I knew I’d have to connect to the new thermostat.

I screwed the back plate of the new thermostat on the wall and pulled the wires through it, leaving that silly little switch behind the plate. I then began matching the wires to the labeled slots.

And that’s when I realized I had a problem: one wire was labeled RH but there was no slot labeled RH.

Understand that I have never done anything like this before in my life. I had no idea what might happen if I did it wrong. I certainly didn’t want to short out an otherwise functioning heat pump. Or cause a fire.

So I paged through the instruction manual and found the toll-free help number. It was midday on a Sunday and I didn’t have much hope of reaching a real person to help me, but I picked up the phone and dialed anyway. After navigating through a brief menu system, a man answered. I gave him my name and phone number per his request and read the model number off the thermostat’s packaging. I then told him about the RH wire. He asked if there was a wire labeled R. When I told him there wasn’t, he told me to put the RH wire in the R slot. Easy as that.

While I had him on the phone, I confirmed something that I had already suspected: that there was a jumper wire running between the R and RC slots in the Honeywell unit. He confirmed that there was. I told him that my old thermostat had a jumper wire in the same slots and asked him to confirm that I wouldn’t need to insert them in the new thermostat. He told me I was correct. He then assured me that I’d have no problem completing the installation, but if I did, I should call back.

Great customer service from Honeywell!

Thermostat installation
It wasn’t easy, but I got all the wires tightly fastened in the right slots.

With some effort, I managed to get all the wires into the right places. I have medium sized hands and struggled with the tight space — I can’t imagine how a man with large hands could do this at all. Maybe with tiny needle-nosed pliers? I got the wires in place and screwed them in tightly.

Then I pulled the batteries out of the old thermostat and put them in the new one’s control box. I fastened the box onto the wall plate. It lit up with the temperature.

Finished!
The completed installation.

I flicked the switch to Heat and left the Fan switch set to Auto. I tapped the temperature up button a few times to set it to 70°. The heat came on immediately.

Looking good so far!

I cleaned up my workspace and finished my cocoa.

It didn’t take long to realize that the heat was now working. The temperature crept up, one degree at a time, over the next hour or so. Soon the upstairs was as toasty as downstairs.

I pulled the extra blanket off the bed. I wouldn’t be needing it that night.

One final note: The guys reading this might be thinking that I’m making a big deal out of nothing. After all, you guys probably replace thermostats or do similar tasks all the time. But while this might be nothing to you, to me, its a real achievement — more proof that I can take care of myself. I’ve done all kinds of minor home repairs in my house, the rental properties I used to own, my camping cabin in Williams, and even my RVs. Everything from drywall and toilet repair to installation of hardware cloth to keep mice out. These are things that most women are never taught to do and never even attempt to do. But women living alone have two choices: they can either ask a man for help — and possibly have to pay for his services — or they can do it themselves. Which do you think is better for us in the long run?

What do you think?