A thermostat is a very sensitive instrument that is made to respond to even the slightest change in temperature. It has fewer parts that are likely to break down than the rest of your air conditioning system, but that doesn’t mean that it can’t present some problems for you. You should still perform regular maintenance to keep it working properly, which will, in turn keep your air conditioning system performing at its best.
If your thermostat cover is not installed properly or it gets bumped, your air conditioner or heater may not start when you turn it on. The base may slip out of level, which means it will not operate properly. A dirty thermometer will not calibrate or operate properly . Wires can become loose or corroded over the years, and they will need to be tightened with a screwdriver and and cleaned with a cotton swab.
Thermostat Maintenance: Check the Calibration
1 Pad a glass tube with paper towels and tape it to the wall a few inches away from your thermostat. The paper towels will prevent it from touching the surface of the wall directly.
2 Wait about 15 minutes. At this point, the mercury will have stabilized. Compare the reading on the thermometer with the reading on the thermostat needle.
3 If there is a variation by more than a degree, you’ll need to check to see whether the thermostat is dirty. Remove the faceplate; it is usually held in place by a friction catch or a snap. Blow away any dust you see inside it. Do not use a vacuum cleaner; the suction power will be too great. If you see accessible contact points, rub a new dollar bill between them to clean them up. If the element is coiled, you can use a soft brush to clean it up.
4 If you see a mercury vial inside your thermostat, use a level to make sure it is straight. If it isn’t straight, loosen the mounting screws and readjust the vial until it is level and then re-tighten the screws.
5 Check the thermostat again to make sure it is giving you the same reading as the thermometer. If it is not calibrated properly, the thermostat will need to be replaced.