Why Thermostat Clicks But No Heat, Furnace Doesn’t Start?

I love mysteries and puzzles. In fact, I can’t get enough of them. There’s actually a puzzle room here in Sacramento that I’ve been meaning to check out. From what I gather, the concept is simple: you and your group get “locked” in a room and have to decipher clues to solve a puzzle in order to “escape.”

My reputation as a mystery and puzzle lover is somewhat well-known, so folks keep suggesting I go down to Midtown and check it out. I probably will, but I also tell them that I get plenty of puzzles in my day job as an HVAC tech as well.

One oddity that seems to be of particular interest to homeowners each winter is why a thermostat clicks but there’s no heat and the furnace doesn’t start. The truth is, there can be several reasons this happens. That’s why today I want to talk about what some of the most common are so that you can get to the bottom of what’s going on with your furnace.

Common Reasons Why Your Thermostat Clicks but There’s No Heat

I’m aware that not everybody feels the same way about puzzles as I do—especially when it comes to solving mysteries related to problems with their furnace. In many ways, that’s a good thing; if homeowners don’t know what they’re doing, they can actually do harm to themselves or their appliances while trying to fix things.

…if homeowners don’t know what they’re doing, they can actually do harm to themselves or their appliances while trying to fix things.

If you are comfortable working with your furnace, however, there are a few simple things that you can do to try to figure out why your thermostat clicks but there’s no heat. The most common reasons why your furnace doesn’t start—and some recommendations for what to do if you want to try and solve this puzzle on your own—are:

• Your filter is dirty. A clogged filter is probably the most common reason for this problem, so it’s a good place to start investigating. Take a look at your filter and, if it’s really dirty and clogged, it means there’s restricted airflow to your furnace. This may be keeping it from being able to create heat. Replace your filter and see if that fixes the problem. And remember, I always recommend that folks change out their filters every month or two so that you can keep your furnace running as smoothly as possible. Remember too that a clogged filter means that your furnace efficiency is low, which results in high heating costs. Clean filters can do wonders, folks!
• The gas supply is off. If you’ve got a gas furnace, make sure that your gas supply valve is open. If it isn’t, carefully turn it on and see if that fixes the problem. If it doesn’t, and you smell gas, it’s a good idea to turn off the gas supply and call a pro. Gas leaks are dangerous. Do not try to fix this problem on your own.
• Your thermostat is on the wrong setting. In order to activate your furnace, your thermostat needs to be set to a temperature above your current room temp. Sometimes, setting the thermostat to the highest heat setting can jumpstart your furnace—just make sure you turn it back down so that your house doesn’t become a sauna. Once you’ve done that, check to see that the system switch is in the HEAT or AUTO position, and that the fan is set to ON or AUTO. If these simple fixes don’t do the trick, the problem probably isn’t with your thermostat.
• The furnace is cut off from the power source. It isn’t all that uncommon for a breaker to trip and cut off power to your furnace, so I’d recommend checking out your electrical panel to make sure this hasn’t happened. Also check the power switch next to the furnace and make sure it is in the ON position.
• The pilot ignitor is dirty. This is another common problem for gas furnaces. When the ignitor gets dirty or clogged, the furnace can’t properly ignite. This fix is definitely a job for the pros, but if you’re familiar and comfortable working on your furnace, you can turn off the power to your furnace, take the front panel off, and inspect the ignitor. If it looks dirty, give your local HVAC experts a call.

Why You Should Call a Pro When Your Furnace Doesn’t Start

While I understand the urge to want to fix problems like this on your own, it’s always a good idea to call a friendly HVAC repair person to come have a look at your troublesome furnace and thermostat. I say this because it can be pretty dangerous to work on a furnace (especially a gas furnace) unless you really know what you’re doing. And if puzzles aren’t your thing, why not let someone who loves them figure things out for you instead?

…it’s always a good idea to call a friendly HVAC repair person to come have a look at your troublesome furnace and thermostat.

Just be sure that you don’t delay furnace repair because if the problem goes on for too long small problems can escalate into much larger (and much more expensive) ones. Plus, having a malfunctioning furnace in your home is a real safety hazard.

In addition to inspecting your furnace and fixing your problem, HVAC professionals can also do a furnace tune-up to ensure that it’s in tip-top condition and that it will keep running smoothly. In fact, I even recommend scheduling an annual furnace tune-up so that you can effectively prevent problems like this one from happening in the first place—and extend the lifespan of your furnace. As much as I love solving puzzles, I love healthy, functional, efficient furnaces even more.

At Bell Brothers, we believe in the whole-home approach to energy efficiency, safety, and health. Our experienced furnace experts would not only be delighted to fix your furnace, we’d also be happy to make sure your HVAC is running efficiently so that your home stays as comfortable and safe as possible. Contact us today to schedule a free consultation.

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Image courtesy Lopolo