It's nearly winter here in the midwest, and that's the time of year that many people find out that their furnace isn't working.
Fear not, just because the heat won't come on, doesn't mean you have to panic and call a repairman.
Here's a quick troubleshooting checklist anyone should be able to do to get things working:
1. Check the batteries on your thermostat. Replace them even. Bad batteries can cause the whole system to go off. Or maybe someone (your kid) played with the thermostat and turned it off, or broke it. Thermostats are under a hundred dollars, sometimes under $50 at your local home improvement store. Changing a thermostat is more complicated than changing a light bulb, but less complicated than changing a bad breaker.
2. Check the air returns to make sure nothing is blocking air flow TO the furnace. Gas furnaces have a safety feature where they kick off if they can't pull in enough air. This is to prevent catching themselves on fire
3. Check the vents- to make sure they aren't blocked, preventing proper air flow (see #2)
4. Check your breakers. Maybe one tripped, shutting off power to a part of the furnace. Like the main or secondary blowers.
5. Check the filters- a clogged filter can prevent proper air flow. (See #2)
6. Look for an error code light. For example on my Trane, there is a curcuit board with an LED. Through a window in the front access panel, you can see the light blink. Count the blinks. Take off the panel off (when the furnace isn't running)and there should be a chart that tells you what the blinks mean. It might be a return heat sensor (upper limit) that's gone bad (ours has three times in 12 years). If it goes out, the furnace thinks it's too hot and shuts off. (See #2)
7. Check to make sure the panels are on right- they have to have a good seal to prevent bringing in outside air. If a panel has been knocked loose, the system may shut off- similar to what happens when you open the door to your dryer.
8. Get your make and model number and google, google google. You might find it's some simple other problem.