by Ben Wanner of Pro Service Mechanical
You wake up in the middle of the night or come home from the holidays only to find that your house is freezing. Why is the furnace not working? Many times you are going to need to call the Pros at Pro Service to get things going again, but before you do I suggest using this quick checklist to see if it is a simple problem you may be able to solve. It could save you the cost of an emergency service call and get things heating up right away.
1. Check Your Thermostat
The first thing you want to do is make sure your thermostat is set to heat. It can be easily moved by accident when dusting or cleaning etc. Some thermostats may not work if the battery dies so you may want to check this as well. This often requires carefully removing the face-plate and taking the batteries out of the back.
2. Check the Breaker
This seems obvious but it is easy to forget. This may be a sign something else could be wrong but resetting the breaker could get your heat back on quickly in a cold situation.
A dirty filter can cause all kinds of problems with your furnace and failing to change the filter could significantly reduce its life so change it regularly. Some newer furnaces will actually shut down if the filter becomes plugged.
4. Check the Emergency Shut Off Switch
Most homes will have an emergency shut off switch located in the furnace room or at the top or bottom of the stairwell. It looks like a light switch and often has a red cover on it indicating it is a switch for the furnace. It may have been accidentally mistaken for a light switch and shut off by a guest, cleaner or a member of your family. Check to see if it is on. It is also not a bad idea to turn the furnace off for a few minutes and on again as it can reset a temporary problem like an iced up vent that is now clear and the furnace might now start. Again this would be a temporary fix and a service call may still be required but it could get the heat back on in the short term.
5. Check the Pilot Light
If you have an older furnace it may have a pilot light. It may have gone out for one reason or another. If you are comfortable safely relighting a pilot light then this might be an easy way to get the heat back on, however you may have a problem with the thermocouple or even possibly the heat exchanger so I suggest you have a service professional come look at it very soon. Again this is not something we recommend a homeowner do on their own unless they have experience lighting pilot lights on natural gas appliances.
6. Check the LED Code
Often there is a light flashing on newer furnaces at the bottom compartment on the front. The flashing creates a code that can diagnose what is wrong with the furnace. The code is sometimes printed on the outside of the door and can tell you what may be happening that is causing the furnace not to run. Sometimes the door has to be removed to reveal the LED code. I suggest turning off the power to the furnace before removing the door and taking a picture of the LED codes with your cell phone. Put the door back on before turning the power back on. Again this is only something I would suggest if you are comfortable. Never do anything beyond your comfort zone with your furnace and always disconnect the power before removing any of the doors or panels. Sometimes an LED code can reveal something simple like a plugged filter or an iced up exhaust vent but most of the time you are just gathering information to tell the service company over the phone when calling.
7. Check the Plastic Vent Pipes Outside
Newer high efficiency furnaces will have a plastic pipe exhausting the combustion gases to the exterior and will have another plastic pipe for bringing in fresh air to burn the natural gas inside the furnace. If these become blocked the furnace will shut itself down for safety reasons. If these are on the roof then checking this may not be a safe option for the homeowner, but they are often vented out the wall on the side of the house. If they become blocked with ice or snow and you can remove the obstruction safely and without damaging the venting then do so. You may also need to disconnect the power to your furnace after this for a minute or two then turn it back on at the breaker or emergency shut off to let the furnace reset itself. Keep in mind that this may get the heat running temporarily but you may want to have a service professional come out and improve the vent arrangement to prevent this in the future.
If we still have not fixed the problem it is time to call in the Pros at Pro Service. Having a professional with the tools and experience will save you time and money, and they may be able to identify issues that may cause you problems down the road. We recommend you have your furnace serviced annually by a Service Pro for increased longevity and reliability.
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