Furnace Repair | When to DIY and When to Call the Experts

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Posted February 15, 2018

It’s happened to the best of us — we get used to that weird thing that our appliance does, or we stop worrying about the funny noise something in our home makes. However, sometimes what we brush off or tune out can be part of a much larger problem. We’re here to shed light on what’s normal and what you should consider fixing when it comes to furnace repair.


1. Furnace cleaning is necessary, but you won’t always need to make a service call.

If a filter gets too dirty, it can block clean air from flowing through your home leaving your home chilly. Sometimes this means that it will kick on, but it doesn’t stay on long enough to heat. When your furnace is overcompensating to keep your home warm, it can wear out quickly or shut down completely. Change your air filter every 1-3 months. Learn more in our blog post about your different air filtration options.

Pro Tip: Turn off your furnace’s shut off fan and switch your thermostat to off when changing filters.

2. Your furnace fan should not always be running.

If you notice that your fan is always blowing, you might have one of a few problems. Your fan, when set to “auto,” should only run when your furnace is in the middle of a heating cycle. If this isn’t the case, then you might be having one of the following problems (Hint – the first two you can DIY):

  • Your fan isn’t on the right setting

    To check if this is the problem, set your thermostat a degree or two below the current room temperature. Then check to see if after a few minutes it reaches that temperature. If it doesn’t, then your furnace may be overworking to heat up. This could mean you have a problem with heat distribution in your home. It’s easy to bundle up in that room that’s always cold or wear short sleeves in the warm parts of your house, but ignoring hot and cold spots only raises your heating bill.

    Make sure your thermostat fan is set to “auto” and not “on.” The “on” switch will force your fan to run even when it doesn’t need to be. This can raise your monthly bill and waste energy by running continuously.

  • Your fan manual limit switch is set to “override”

    Locate your fan limit switch, and check to see if the white button is pushed in. If so, then your furnace is in “always on” mode. Pull the white button out to reset your limit switch.

  • If the above options don’t fix your problem, then you likely have a short in the wiring of either your thermostat or your fan switch. For your safety, only a licensed professional is qualified to fix this furnace problem, so contact you local HVAC technician for your furnace repair.

3. Stop ignoring that eggy smell coming from your furnace.

Natural gas is both odorless and colorless, but to help detect gas leaks, mercaptan has been added to gas lines. When combined, mercaptan causes gas to have a rotting egg or sulfuric smell. If you notice this smell, immediately shut off your gas lines. Leaking gas is no joke! Contact your gas utility company to remedy the leak. If open flame ends up anywhere near the gas leak, you may be looking for home fire repair rather than furnace repair.

4. A funny smell the first time you turn your furnace on is typical.

It seems weird, but the funny, maybe even musty, smell you notice at the beginning of the first heat cycle of the season is dust being burnt off from inside the furnace. The smell shouldn’t last more than a day or two. As long as it doesn’t have that sulfuric scent that we mentioned before, you should be totally fine. Nothing to worry about here!

5. You shouldn’t tune out the rattling noise coming from your furnace.

Some noises are innocent, and you might come to expect them, but some sounds are an indicator of something much worse brewing in your furnace. If it’s rattling, then that could be a sign that your blower wheel is out of alignment, dirty, or has a loose screw or two. This sort of noise isn’t too dangerous and is likely something you can DIY, but letting it go on for too long can cause damage over time to your unit. Learn about other furnace sounds to watch out for in our blog post, furnace noises in the winter.

6. There is no reason you should have to frequently ignite the burner yourself.

Occasionally, a relight might be necessary – if your pilot light goes out – but once the furnace is lit, it should be staying ignited by the burner. If it’s not, then this could lead to very poor heating which will drive your utility bill up. First, check to make sure that a draft isn’t the source of wind blowing out your pilot light. If you’ve got all windows and doors closed, then you can determine if it’s your burner that needs adjustment or cleaning. Because you are dealing with something that could pose a safety hazard, you’re going to need to have an HVAC technician take a look at the burner. You wouldn’t want to inhale carbon monoxide or cause a gas leak accidentally. Having an annual home maintenance plan would prevent this from being an issue for you.

While most preventative maintenance can be done by you or a member of your household, some furnace repair tasks are too dangerous for any unskilled technician to take on. Contact a Hiller service technician if you have any questions about the safety of your home repairs. As always, we’d be happy to take a look at your furnace or any of your other heating and cooling units.

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