Blank Thermostat | HVAC Repair

Posted on: Apr 11, 2019

Discovering a blank screen on your thermostat is upsetting. It means you can’t turn your HVAC system on or off, check the current temperature, or make changes to your programming. There are a few reasons why you might see a blank screen. Here are some common ones with advice on whether you can fix the problem yourself or need the help of one of our capable HVAC technicians.

No Power


Some thermostats run on batteries, while others are wired and receive power via the HVAC system. If yours is battery-powered, putting in fresh ones may be all that’s needed to bring it back to life. If the unit is wired, it’s best to have a trained technician check for loose connections or wiring that needs replacement.

Tripped Circuit Breaker


An overloaded circuit or power surge can sometimes cause a breaker to trip. To fix this, locate the “AC” or “HVAC” breaker in your home’s electrical panel. If it’s been tripped, switch it all the way off and then on again. If your thermostat screen lights up, but the breaker trips again, don’t reset it a second time. Instead, call in a pro to investigate why.

Tripped Safety Switch


If your HVAC control is wired, the screen will go blank if a system safety switch is activated. If your system is in cooling mode, and the condensate drain line is clogged, the float switch can trip to shut off the equipment and prevent a water backup. When you’re running the furnace and it overheats, the high limit switch will shut down the system to prevent equipment damage or a fire. Both situations warrant an expert diagnosis to find and fix the underlying cause.

With the A/C, unclogging the drain line, emptying the collection pan, and resetting the switch may be all that’s necessary. Or, the switch may be faulty and need replacement.

With the furnace, the sensor on the limit switch may be dirty, the blower motor may stop working properly and overheat, or there might be an issue with a circuit board, contractors, or the gas valve.

Worn Out Thermostat


Like other types of equipment thermostats eventually, wear out. If yours is 10 or more years old and has quit working, the experienced team here at Airco Service Inc. can install an energy-saving learning model. If you’re faced with a blank thermostat screen and need reliable advice, contact us today.

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