How to Troubleshoot Your HVAC Thermostat
That distinctive chill in the air – particularly at night – means fall has arrived in the Denver Metro area. Have you turned on your furnace yet? If your heating system is not working properly, the problem could be your thermostat.
Thermostats are typically reliable, but they can have issues.
Here are some things you can do to troubleshoot your thermostat before calling for professional service:
- Check that the thermostat is on the appropriate setting — “Heat” or “Cool” and that the fan is set to “Auto.” (It’s easier than you may think for the switches to get on the wrong setting.)
- Set the thermostat 5 degrees higher (or 5 degrees lower in the summer) than the current room temperature and check that the furnace (or A/C) comes on.
- Check the main circuit breaker as well as the furnace “On / Off” switch, located next to the furnace, and ensure that both are on.
- Turn the power off by switching either the circuit breaker or the switch, located next to the furnace to “Off”, then “On”. This will reset the controls.
- On older systems, verify that the pilot light in your furnace is lit.
If none of these steps gets the furnace to turn on, the thermostat may be culprit. You can do an additional check to determine if the thermostat is bad:
- Turn the power off by switching the circuit breaker off. Gently remove the cover of the thermostat. Check the wires to make sure they are firmly attached to their mounting screws. Carefully reattach any loose wires and tighten the screws.
- Unscrew the red and white wires (generally for the furnace) or the red and yellow wires (generally for the air conditioner). Hold the wires as you loosen the screw to keep them from falling into the wall. Wrap the two wires together and turn the breaker back on. If the unit comes on, the thermostat is possibly bad.
If you have a programmable thermostat, there are a few other steps to try:
- Make sure the thermostat is set to the correct mode (cool or heat)
- If your thermostat requires a battery, make sure it has a fresh one.
- Enlist an assistant to stand at the furnace, while you are at the thermostat. Slowly raise the heat settings. The thermostat should make a clicking sound, and the furnace should also make a sound. If the furnace does not make a sound, the thermostat is possibly not sending a signal and needs to be replaced.
Once you’ve determined that the thermostat needs replacing, you’ll need to contact an HVAC contractor. If you do need a new thermostat, and currently have an old one, consider upgrading to one that is programmable. They cost a little more, but will save you money on your energy bills when programmed correctly – and you won’t sacrifice comfort.
Northern Climate Control specializes in thermostat repair, maintenance and installation. We are fully licensed and insured and have been serving the Denver Metro area since 2003.