My Thermostat Stopped Working
- 1). Turn off and unplug the furnace, air conditioner or other device controlled by the thermostat. Open the front access panel, remove the air filter and clean the filter with water and dishwashing liquid if the filter is reusable, or replace if it's disposable. Dry the filter completely and replace it in the unit. Close the access panel and restore power. If the filter is dirty, this may affect the ability of the thermostat to control the device accurately.
- 2). Open the battery compartment on the thermostat and remove the old batteries. Set new batteries inside the compartment, pushing the flat end of each battery against a spring in the compartment and pressing the other end of the battery in until it is firmly in place. Thermostats often use "AA lithium" batteries, which can be purchased at most hardware or grocery stores. Close the battery compartment.
- 3). Look around the thermostat for conditions that may be affecting the thermostat, such as drafty windows, doors or halls, or if it is located near a furnace vent or other heat source. Block potential drafts and close the heat vent, if possible.
- 4). Open the thermostat cover and use a small brush to gently dust inside to remove any dirt or debris. Clean the contacts inside the unit, which look like small metal plates, with the brush. Use a pencil eraser to clean sensors inside the unit.
- 5). Fill any large gaps behind the thermostat with a small amount of insulation that is taped into position with electrical tape to prevent drafts from altering the thermostat performance. Close the front cover.
- 6). Contact a service professional for assistance if these steps do not resolve the problem.
