Your Honeywell thermostat provides a simple way for you to adjust the temperature in your home. Essentially, a thermostat functions as a switch to turn the heat or air conditioning on or off. If the thermostat is not functioning properly, there are a number of ways you can try to troubleshoot it yourself.
Blinking Honeywell Thermostat Screen
If the screen on your Honeywell thermostat is blinking, the batteries powering it may be dead. Try replacing the batteries and see if that resolves the issue. Some Honeywell models also have a low battery notification, which will use a tone or the words "replace bat" when it's almost time to replace the batteries.
A blinking screen can also be related to issues with compressor protection. In this instance, a message reading "cool on" or "heat on" may be part of the blinking screen, as well.
Additional Analog Honeywell Thermostat Issues
Analog Honeywell thermostats may have additional, unique issues. For instance, if the unit is not level with the wall perfectly, the mercury switch inside may be tilted. This could cause it to read the room's temperature incorrectly, which will make the heat or air conditioning kick on too often or not frequently enough. Use a level to verify that this switch is situated evenly. Ideally, the thermostat should also be located at least 5 feet from the floor, and it should not be placed within a closet or cabinet.
If your analog Honeywell thermostat is still not functioning correctly, try removing the door to the unit. Look for dust or debris and clean the unit off using a soft cloth.
Another possible issue with an analog thermostat is its wiring. You should be able to see a series of colored wires within the thermostat box. Use your owner's manual to ensure these wires are connected properly. If they are, your issue is more likely related to the furnace or air conditioner itself.
Thermostat problems can also be related to the circuit that the furnace or the air conditioner are on. Check the circuit breaker to ensure that it hasn't been flipped.
Additional Digital Honeywell Thermostat Issues
If the screen of your Honeywell thermostat is blank, you should first check the furnace or air conditioner to be sure both are on and functioning properly. If the door to the furnace is open, for instance, the thermostat display may be blank. A fix could be as simple as closing the door of the furnace. You should also check the circuit breaker to be sure the breaker hasn't flipped.
If you notice that your house is suddenly too hot or too cold, the temperature sensor on your thermostat might be malfunctioning. Use a thermometer to measure the air temperature in the room that houses your thermostat. If it doesn't match the temperature displayed on the unit, the sensor is likely broken. In some cases, it may be more cost-effective to purchase a new unit, rather than to replace the sensor alone.