Troubleshooting Electronic Thermostat Problems

Adjusting an electronic thermostat.
  • 1 hours
  • Intermediate
  • 0-200

If you are having problems with your heating or air conditioning, the cause can sometimes be your electronic thermostat. While these little devices are fairly reliable, people sometimes find they prevent heating pumps, AC units or hot water from kicking in when they are intended to.

You may decide your thermostat problem is too difficult for you to manage, and you need assistance from a professional, or you may decide to do the job yourself. If you have a few basic home improvement skills, there is no reason you should not be able to follow some simple guidelines to troubleshooting your electric thermostat quickly and easily.

The Heat Doesn't Come On

There are many reasons why the central heating doesn't come on. Check your electronic thermostat for any signs saying, 'No Power.' You should check the circuit breaker in your thermostat connection is not tripped, or the electrical connection is lost in some other way, for example by loss of battery power. These problems are easily remedied by finding the exact problem and resetting or replacing the damaged parts.

Before you check for loose wires or other electrical damage, ensure the electricity has been turned off at the breaker box. If the circuit breaker has been tripped, then check your system for signs of a short circuit. In addition to checking all of the electrical cables, also check that the thermostat is completely clean. Dust between the connections may cause the device to think there is no power, when all the machine needs is a good brush down with a soft, shoe-cleaning type brush.

Too Much or Too Little Heat

old thermostat wiring

Another common problem is the heat control in your thermostat is awry. There could be a number of reasons for this, including problems with the electrical wiring (check your thermostat for loose connections in the screw terminals), or even something as simple as the thermostat being mounted crookedly.

If you have been having this problem with your machine since it was installed, you may need to level out the top of the thermostat, as an incorrect mounting can cause the temperature gauge inside the device to be unbalanced, giving a false reading. Also try and adjust the heat control, known as the ampere. The setting for this will be included in your electronic thermostat's manual.

Furnace Turns Off Too Soon

This problem, also known as Short Cycling, can be caused by a number of events, including loose wiring (again). Before you finish checking your system, have a look and ensure all the screw terminals are tight, the wire is in contact with the connection, and there is no crossing of exposed copper wire within the thermostat. Another cause of Short Cycling can be dirt. You may need to clean the switches using a piece of bond paper, wiped gently against the coil, the contact surfaces, and between the contacts. You may also need to adjust the ampere again, as described in the manual.