furnace troubleshooting

Today we will cover some basic furnace troubleshooting. Now, all furnaces are not created equally. There’s quite a difference between a newer, modern furnace that utilizes electronic ignition and a furnace that is 30 years old and uses a standing pilot light. When it comes to furnace troubleshooting, not all answers will apply to all furnaces. So we’ll just cover some of the more common issues related to older furnaces and cover newer furnaces in a later blog.
If your furnace has a standing pilot flame, it is likely at least 25 years old. I’ll just say right here that if this is the case, you’re better off just having a new furnace installed. Not only are they safer to operate, but they will also be more efficient. But let’s say it’s late on a Friday night and your old geezer of a furnace has stopped working. Obviously you’re not going to get a new one installed at this moment, so let’s at least try to get you some heat for the weekend.
If the pilot flame has gone out, oftentimes it can simply be re-lit and you’re good to go. But what if it doesn’t stay lit after you let go of the pilot button? Chances are you have a bad thermocouple that will need to be replaced. Now I don’t recommend that you try and replace this yourself, unless you’re experienced at it. Thermocouples need to be properly aligned and tightened. I will always recommend that you have your furnace repaired by a competent HVAC company (like us!). However, there are many do-it-yourselfers out there who think they can fix anything, so here you go!
Now what if the pilot IS lit, but the burners won’t come on? Could be a number of things, such as a bad gas control valve, or an electrical issue, such as the gas control is not getting the signal to energize. Now this could be anything from a defective thermostat to a bad transformer, or a simple SSU fuse that has gone bad. Unless you’re an expert furnace troubleshooter, I’d leave this diagnosis to the pros.
Say the furnace burners DO light, but go out after a few minutes without the main blower motor coming on. Most likely you have a failed blower motor, which in turn causes the furnace’s temperature limit control circuit to open in order to keep the furnace from overheating and burning your house down. If this is the case, you’ll need a new blower motor installed. It’s also possible that the motor is okay, but there could be a defective motor relay preventing the motor from coming on.
In short, NEVER….EVER! attempt to repair your own furnace (or even your neighbor’s) unless you are 100% SURE that you know what you are doing. Furnace troubleshooting isn’t always simple, and often the repair is even more difficult. It’s nice to have an idea as to why your furnace has stopped working. But it’s best to leave the repairs to a pro who does this for a living.
If you need help with your home’s heating system, call Basset Heating & Air Conditioning at 719-392-0032. Serving the Colorado Springs area and surrounding communities.