I never posted originally about my recent HVAC woes, so I’m telling you now – I had them.

One day I came home from work and B told me that the furnace/blower just started running all by itself, so she tried messing with our thermostat but couldn’t get it to to turn off. Well, I couldn’t either – toggling the ‘Fan’ switch between ‘Auto’ and ‘On’ had no effect. Neither did the main switch (Heat, Off, Cool). 😦 I ended up turning the power off to the surface at it’s dedicated switch. Because of all the other house work going on, I never had a chance to troubleshoot further.

Then I saw how bad the little wall looked (the one the thermostat was on) trying to skim coat around it, so I pulled out the thermostat so I can do it the right way. At this point, regarding the little HVAC problem we were having, I thought, “Hmmm…maybe it was the thermostat”. So I turned the power back on to the furnace and guess what – it came on again. Booo!

Being too busy still, I put this problem off to the back burner again. Then recently, I received an email telling me that a particular awesome new thermostat is back in stock, so I ordered one. But I realized that this new thermostat is going to be no good without a working HVAC system, so I did some more troubleshooting. I was thinking in my mind that I had a wiring problem, so I removed the front panels and took a photo of the wiring, and also tested continuity between all the wires/terminals. Armed with a photo and some notes, I started scouring the internet. Of course I’m not the only person with the same problem in the world says Google. There were a few possible causes for this particular problem says the ‘experts’. The 3 most likely causes were:

  1. Dirty air filter
  2. Bad limit switch
  3. Bad relay

I just happened to have a new air filter because I knew it would be insanely dirty with all the construction that’s gone on the last couple years, so I decided to replace my old grungy one. Then after replacing the front panel, I turned the power back on to the furnace and it made a noise for a second, then silence! I don’t know how that the furnace could possibly know that the air filter was dirty, but it seems that it does. Although, I’m still not 100% convinced that it does. I’m wondering if something happened at some point a while back (maybe the thermostat went haywire?) and the blower got stuck on…and removing the front panel triggered the front safety switch, essentially resetting it? I have no idea…I’m just glad I don’t have to continue my wiring/electrical troubleshooting because after verifying the integrity of the wires (or replacing them) it was only going to get more difficult from there. And paying someone minimum $100 just to come out, then who knows how much more for additional labor and parts did not sound pleasant.

Now, it is possible that something could still be wrong, but I won’t know until I install my new thermostat. It should arrive tomorrow, but I’m not sure if I will have time to install it.

What kind is it you ask?

It is a Nest Learning Thermostat. Yes it is pricey, but it’s ease of use and capabilities is well worth the money…not to mention that it actually passes the ‘wife test’.

Oh, how did my ‘patching’ come out for where the old thermostat was? I will follow up when it’s done…maybe within a week or 2. I will also come back and post about the new thermostat once I have it installed and (hopefully) working.

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