Broken Furnace? Try These Troubleshooting Tips Before You Call an Expert

When you wake up on a chilly winter morning and it’s so cold inside you can barely force yourself to get out from under the covers, then chances are you have a furnace malfunction. As a furnace is an expensive, essential home appliance, it’s easy to start to panic. If your furnace is not kicking on, it makes sense to first check it’s not a simple, easy-to-fix furnace problem rather than a more complex furnace part failure.

What should you do first when your furnace stops working? Our broken furnace troubleshooting guide aims to help you to get your furnace back on and working. Simple, effective and requiring no specialist knowledge, the following six easy steps are worth a try to hopefully get your furnace restarted or at the very least get a good idea of why your furnace has stopped heating your home.

1. Check Thermostat Settings

Let’s start simple. The first step is to check that your thermostat is correctly set. Depending upon its location, it could have been knocked or maybe a family member altered the settings without you realizing. As simple as it sounds, it’s well worth double checking that your thermostat is set to “heat”. If your thermostat is not set to heat, then your furnace just won’t power on.

If it’s definitely set to heat but there’s still no sign of your furnace firing up, check any thermostat timer settings. Even if you don’t make use of them, someone could have inadvertently pressed a button – with controls often all in close proximity, it can be easy to select the wrong option inadvertently. If you adjusted your heating before bed and wake up to a freezing cold house, then you may well have accidentally hit an option you didn’t intend. Check the different options on your thermostat or try cycling through modes to see if this results in your furnace kicking in.

Once you’re sure that your thermostat is unequivocally set to tell your furnace that heat is needed right now and still nothing is happening, you may want to just double check your thermostat batteries, if it’s not a directly wired-in model. Calling out a repair person for a two-second thermostat battery change can be an expensive (and embarrassing) mistake. While not all thermostats do take batteries, for the ones that do changing the batteries is easily overlooked, especially after a prolonged period when you’ve not used your furnace.

2. Check Furnace Filter

Take time to check on the condition of your furnace filters. If you weren’t aware your furnace even had filters, then chances are this could well be the answer to your furnace problem. Check your manufacturer’s manual for filter location, access, replacement part numbers and changing details. Furnace filters need cleaning, and ideally changing, on a regular basis. Furnaces suck air through a filter before heating it and sending it out into your home. If your furnace is located in your laundry room, you may have problems with extra lint and particles from cloth fibers sticking to your filters. If this is the case, you will need to be more vigilant and check your furnace filters on a more regular basis.

Locate your furnace filters and open the compartment. Carefully remove your filter in accordance with your furnace manufacturer’s instructions. Does it seem dirty and clogged up? You will need to replace your furnace filter. Some furnaces will shut off automatically when the filters get clogged. Others are less sensitive and will continue to work but often at a reduced capacity. If you’ve been wondering why your furnace makes a whistling noise, it could well be caused by a clogged up filter.

While it is recommended that you replace your filters rather than just cleaning them off, you may want to quickly brush off the dust to see if this is the actual issue. Even if your furnace does have other related or unrelated problems, then you’re still going to need to replace your filters as soon as possible. A lot of homeware store furnace filters use an oily finish to help ensure that dust particles are effectively trapped. Once this type of filter is covered with dust, it will be unable to perform effectively and cannot be cleaned.

3. Check Power To Furnace

The next step is to check that your furnace actually has power. Simple as it sounds, you’d be surprised how many people forget to check this essential step before calling out a furnace technician. A quick and simple way to check that your furnace has power is to set your furnace fan to “On”. This will let you know straight away whether or not your furnace has power available. If you don’t hear the fans coming on, then try the following steps:

  1. Check your furnace switch. Most furnaces have a dedicated switch that could have been accidentally flipped. They are usually located right by your furnace and often resemble a light switch. Flip it and see if that kicks your furnace into action. No joy? Flip it back to its original position and try step two.
  2. Check your home circuit breakers. Your furnace should be labeled on your circuit board, make sure that the switch is flipped to the on position. If your furnace is not correctly labeled, flip any circuit breaker that is not in the correct position to make sure that you’ve got power to your furnace.

4. Check Furnace Gas Valve

If you have a problem with your gas-powered furnace, double-check that the gas supply valve is set to open. This valve will be no less than six feet away from your furnace and usually won’t need to be operated. You could also check any other gas-powered appliances in your home to make sure that it’s not a problem with the gas line itself rather than your furnace.

Always follow your furnace manufacturer’s recommendations and pay particular attention if you think you may have a problem with your gas-powered furnace. Do not hesitate to call out a professional if you have any suspicions over the gas supply and connections in your home. Newer gas furnaces should cut off if they detect any abnormalities; however, it is still advisable to make sure you’ve got a carbon monoxide detector for any gas heating appliances. This is essential for older models that often burn less efficiently and have less built-in safety detection features.

5. Diagnose Problems

If you’re still out in the cold, then you’ve probably got an actual furnace problem rather than just a simple misconfiguration. Whether you intend to fix your furnace yourself or call in a professional, it’s always good to know what exactly this is going to entail. While the chances are getting somewhat slimmer, there is still a small chance of a quick fix, so let’s take a look at how to diagnose your furnace problem depending on its age.

Furnaces Over 25 Years Old

If your furnace is twenty-five years old or more, then it’s not likely going to have the same code system to diagnose problems as more recent models. Older furnaces usually have a pilot light. If this is out, follow the instructions in your manufacturer’s handbook for relighting your furnace’s pilot light. If you don’t feel up to it, call for help or ask a family member or friend for assistance. Be sure to follow all of the recommended safety procedures.

Furnaces From the 1990s and Onwards

Furnaces dating from the 1990s onwards tend to have a light system. Check the small window and look for the power light. When there’s an issue, the light may display a flashing configuration or you may have a digital code displayed. Either way, look up your flash sequence or code in your furnace manufacturer’s handbook. Even if you’re not planning on doing the work yourself, you can still check out part prices and arrive at a rough estimation of a minimum cost for your furnace repair bill. There may be a simple, easy fix solution to the problem, possibly involving the following step of resetting your furnace.

6. Hit Reset

If you’re still not getting any luck, try hitting the reset button on your furnace. Chances are that if your furnace has a major problem, this won’t help, but sometimes a simple reset can solve the problem, especially when your furnace has incorrectly sensed a non-existent problem. If you’re having difficulty locating your furnace reset button, check the procedure in your owner’s handbook. If you frequently need to reset your furnace to get it to work, then you will be still better off calling out a technician in case you need to have some sensors or other parts replaced.

When To Call For Help

If you think you’ve now correctly identified your furnace problem, you could try fixing it yourself. If you do have some experience with this kind of repair work, you could check some solutions, part details, and prices online to help you to gauge the complexity of your furnace repair and whether or not you can fix your furnace yourself.

If you don’t have much experience or the tools you need, though, or if you’ve gone through all of the steps above and you still cannot identify why your furnace is not working, calling out a professional is going to be the safest bet. If you’re worried about the cost of your furnace repair, try to find out what parts you’re likely to need and an estimate of labor. If you don’t have the necessary experience to attempt a repair then doing so will likely push the price up if you have to get someone out to repair your repair work on top of the original problem.

If you don’t already have a regular furnace maintenance person, don’t be afraid to contact a few different places. Once you’ve found someone you like, you could organize them to program a yearly furnace checkup. This will help to reduce the likelihood of your furnace developing any avoidable problems and it will keep your home heating system well maintained and running efficiently.

Final Thoughts

When your furnace has stopped working, it can be all too easy to let panic set in and call out a specialist straightaway. Taking the time to go through our furnace checklist and troubleshooting steps will enable you to avoid calling out an expensive repair person for just a flick of a switch. Also, by identifying and diagnosing the problem, you should be able to provide your furnace repair person with a helpful rundown of this issue so you can get a better idea straight away of the likely cost, timescale, and complexity of your home furnace problem.

When your furnace stops working, methodically go through each of the relevant steps in our furnace troubleshooting guide and rule out paying for a professional to come out unnecessarily. When it comes to large household appliances, we often tend to imagine the worst. You would be surprised, though, just how many times stopping to check the little details can help to resolve a home furnace heating problem.

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