DIYJoe Member Posts: 4. When the system is working, the thermostat does keep the house properly conditioned. Step 1 Replace your "furnace limit switch." Replace the wire or thermostat to fix the problem. Or, if you smell gas, leave immediately and call a repair company. My furnace fan/blower will not work when set to the auto position. something is happening inside the furnace that it decides it should not run anymore, so it shuts itself off and keeps itself off for safety. I go down and turn the power switch on the furnace off and on a couple of times and then you can hear the igniter and the furnace fires right up and will continue to run just fine. Show More. Electric Furnace Troubleshooting. In case the furnace turns off when the thermostat is turned to off, a probable reason is a thermostat that is not working properly. Replacing it is an easy fix. Initially, the burner will turn off and then the blower would turn off as well. Believe it or not, a dirty air filter can actually make your furnace run non-stop because it restricts air coming into your furnace. A dirty air filter restricts air from getting into your furnace. 2. The furnace’s control board thinks that the furnace is overheating so it runs the blower. This is the part of your Furance that heats the air. If your furnace’s motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. Filter – The most common cause of furnace problems is a dirty filter. The furnace blows hot air only in "FAN" mode. Step 6: Clean the Pilot. If the drain is clogged, insert a straightened wire hanger to clear it out. If these tips don’t work then give us a call or find us on Facebook. Improper usage or maintenance of your furnace could result in the furnace not functioning, fires, explosions, property damage, personal injury, or … The thermostat seems to be working but the thermostat is not turning on the furnace… Furnace Blower Fan Wont Turn Off - Hello Richard, I have a problem with my furnace where the indoor blower will turn off.My furnace seems to be heating okay it is just the blower will not shut off. The furnace is a Concord 90% Efficient, gas fired, forced hot air unit with a White-Rodgers mercury switch thermostat, 5 years old. This is most common cause of short cycling. Let’s take a closer look at why that’s the case: When your furnace gets the call for heat, air from your home is pulled into your heating/cooling system and through an air filter. The solution to … Furnace Does Not Blow Air. Other causes of furnace turning off and on. I think what the OP is suggesting is that if the fan is set to auto and furnace comes on, no heat (or at least, very little heat). It is possible for your furnace to run with blower motor off. This switch usually powers the low-voltage thermostat as well as the furnace itself. Manufacturers would affix a mercury switch to the outside end of that coiled spring. Just cool air blows. I would suggest that you check your limit and rollouts to make sure they are all closed with a voltmeter. If you have an older furnace with a pilot light, it is possible the flame might have gone out. Verify the unit has power. Also, the furnace is hot and the gas is burning. Turn the power to the furnace off and disconnect the wires from the thermostat. Those primitive models relied on a bi-metal spring to sense temperature. To turn the furnace back on, relight the pilot light.If it will not stay lit, however, turn off the furnace’s power and gas supply and try the following. December 2019 in Gas Heating. My furnace fan won't shut off automatically. About 4-5 times now when it called for the furnace to warm up the house to 68 f the furnace has not come on. Moving the temp control makes no difference, ONLY toggling the on/off switch on the thermostat will kick on the furnace. When I first turn on my furnace everything works fine. If your furnace is coming on and isn't turning off, you need to investigate the issue, as it could end up costing you excess money on your utility bill at the end of the month. but you didn't tell us anything about the furnace, so we can't provide any more detail. Your furnace’s heat exchanger needs that air blowing over it or it overheats, causing the furnace … 1. I replaced the thermostat and get the same results. Bad Belt. Ensure That Your Requested Temperature is Reasonable. Cause #4 Furnace Blower Motor Not Working. Wait approximately 30 seconds and then turn the thermostat back on and increase the temperature to the desired level. If you furnace filter is clogged, the airflow will be restricted. When the mechanical thermometer is switched to "AUTO", I could hear the click sound from the unit, however the FAN does not start blowing the hot air at all. First, turn off all power to the unit and turn off the gas at the gas valve that serves the furnace. I set my thermostat 70 degree and furnace will work and make my home 70 and turn off but once temperature drops it won’t on again the. Try replacing its batteries if the display on a traditional low-voltage thermostat or wifi thermostat is not indicating power. Many homeowners discover that their furnace is not working when they go to turn it on for the first time of the winter season..