The thermostat is an essential part of your home\u2019s HVAC system. Without it, you have no way to change the temperature in the house or even turn your air conditioning and heating system on and off. If you use a digital thermostat (and you should; they are far more precise and effective than older manual models), a problem you might encounter at one point is discovering that thermostat screen has gone blank, and pushing the buttons does nothing to change it and it won\u2019t turn the HVAC system on or off.<\/p>\n
There are a few reasons this might happen. We\u2019ll go through them and what you can do about them. In many cases, you will need the assistance of a trained HVAC repair technician.<\/p>\n
If the blank thermostat occurs during the day, it\u2019s possible that you have lost electrical power to your house and haven\u2019t noticed it yet. The power loss could also be the result of a tripped circuit breaker that powers the air conditioner or heater. Many thermostats run on low voltage sent from the transformer on the HVAC system; if the transformer loses power, so will the thermostat. Check on the circuit breaker box and reset any switches that have tripped.<\/p>\n
Not all thermostats run off voltage coming from the HVAC system. Some receive power from batteries housed within the unit itself. To change the batteries, you have to detach the faceplate of the thermostat from the wall. Check with the owner\u2019s manual to find out how to do this. Put in fresh batteries and see if this reactivates the thermostat\u2019s display.<\/p>\n
Safety switches on air conditioners and furnaces can be tripped and cut off power to the thermostat. For an air conditioning system, this usually occurs because of water overflow in the condensate pan. With a gas furnace, it\u2019s usually the limit switch tripping because the furnace is overheating. You shouldn\u2019t attempt to fix either problem on your own: call for professional repairs.<\/p>\n
An electric failure in the thermostat unit may be at fault. If the HVAC system is fine and there are no power issues, then a technician will advise you about whether the thermostat should be fixed or replaced. It\u2019s usually advisable to upgrade if you have an older unit.<\/p>\n