5 Causes of a Malfunctioning Thermostat

September 16, 2022

The thermostat is the command center of the HVAC system. It controls temperature throughout the entire home and directs the system to turn on and off throughout the day and night. But when the thermostat starts to malfunction, the entire system is affected.

Repairs will depend on the underlying cause of the broken thermostat.

  1. Failing power source

If the thermostat screen is blank or dark, then the cause is most likely lack of power. Check to make sure the system is turned on and replace the batteries, if necessary. If this doesn’t address the issue, then you could have a tripped circuit breaker.

  1. Loose connections

Loose electrical connections could interrupt the flow of power to the thermostat. Most thermostats have a heating, cooling, and fan connection. Loose wiring, corrosion, and other causes could make it difficult for the thermostat to communicate with the HVAC system.

  1. Dirty thermostat

Dust, dirt, and other debris can cover the electrical and mechanical components in a thermostat and cause it to fail. Turn off power to the thermostat at the electrical panel and remove the thermostat’s cover. Use a small brush to clear away dust and debris, and replace the cover. Turn the power back on and check the thermostat.

  1. The thermostat isn’t level

Most thermostats have a mercury bulb that must be level to operate. If the thermostat is even slightly crooked on the well, the reading on the screen won’t match the room’s actual temperature. You’ll need to turn off the power supply and remove the thermostat. Then, use a level to reattach the thermostat.

  1. Installed in the wrong spot

The thermostat should be located in a part of the home that doesn’t get too hot or cold during the day. If the thermostat is positioned directly above or beneath a register it can shut off too early and leave the rest of the home too cold or too hot. You’ll need to hire a professional HVAC technician to move the thermostat away from registers, windows, and doors. 

If you have any questions about your thermostat or need HVAC service, call Tucker Hill for an appointment.