Hey Mark & Theresa—My furnace is tripping. I know it sounds like the ‘your refrigerator is running so you better go catch it’ gag, but that’s what the home inspector told me. I’m selling a house and I’m worried I might be in for a big repair bill. Can I fix it myself? #PleaseSayYes —Stephen, IL
Stephen, There’s good news—potentially. And maybe not. Also, potentially.
There’s a switch inside a furnace that shuts it down (or what insiders might call ‘opening a circuit’) when it’s working too hard. Typically it’s opening on the high limit, shutting the heater down when the heat exchanger overheats. Perhaps over simplifying: It is suffocating, then having a small heart attack. The ‘your lungs’ equivalent would be trying to jog while breathing through a straw.
The fix can be something as simple as a (very) clogged air filter, which you can easily replace yourself, and for just a few bucks. Here’s how to replace a furnace filter.
If its not that then it may be something in the system itself that requires a pro to diagnose and repair. And this is where you might be talking about some cash. When a furnace is tripping it may be the result of undersized duct work or dirty coils inside the unit. Stay tuned for my speech on this:
No matter how handy you are, you do not have the right tools or know-how to do this work properly.
We work with a trusted HVAC pro for our projects, our own home and this answer. What’s more, not all pros are created equal. When it comes to HVAC, do your homework. HomeAdvsior is a great resource. So is this article on HVAC installation.
In some cases, the switch itself can go bad. However, the furnace is tripping over and over prior to the switch damage in most cases.
Bottom line, you can thank me for zeroing in the cost of your HVAC unit tripping to somewhere between $6 and $6,000 + dollars. And the thing is, most of these problems can be caught with regular inspetions and maintenance. That’s cheap money compared to a big fix.
We really do hope it’s just the filter or a minor repair. Good luck with the sale. Please let us know how it turns out.