Help! My Thermostat is Blank!

thermostat ImageSo you notice your house is too cold or too hot. You glide over to your thermostat to adjust the temperature and notice it is blank.

As you start to panic, your mind immediately jumps into action and thinks about what to do next. Then the fear sets in. Who can I call? who can I trust? Can I do this myself? Will I end up on NBC’s Dateline?

Well, don’t panic just yet. There are several good reasons the power has gone out to your thermostat and several of them are warning signs of something major. But there are also some very minor reasons as well. Lets start from the easy fixes first and move up to the major fixes.

  1. A wire has come loose from the thermostat. The thermostat runs off of 24 volts supplied by the furnace or air handler. If the thermostat wire has come loose behind the thermostat, just remove the front panel and inspect the wires in the connections to the back panel.
  2. Now given that those connections are all good, lets move on to a loose connection at the furnace or air handler. You may see some loose wires or a wire has fallen out of the wire nut at the furnace. That can cut the power to the thermostat since the furnace or air handler supplies the power for the thermostat.
  3. If those wires are good, then look to see if the power to the furnace has been turned off or a breaker has been tripped. Do not reset a breaker as there is a danger if the system has shorted out. But a light switch can be turned on for furnaces without worry.
  4. Maybe the switch and/or breakers all look good. Then the next possibility is a bad light switch for furnaces only (not heat pumps) This will require someone with experience to check and replace. But is relatively inexpensive. This point and the next two will require a trained technician and goes beyond the DIY stage.
  5. By now after all other possibilities have been exhausted, we get to the more serious repairs. Check to see if there is water in the drain pan under the AC coil or air handler. If so, you have a leak in the refrigerant and need it fixed. Topping off with refrigerant only delays the repair that is really needed and in harmful to the environment. This is where you need to call a reputable company with good reviews and highly recommended to come out and determine if it is a leak, where the leak is, and what is required to FIX the leak.
  6. If it isn’t a leak, then there are so many other possibilities that the technician you called for #5 will be helpful to identify the real reason the screen is blank.