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 Freon 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.


Top 4 HVAC Repair Myths

  1. A technician said my coil is rusty therefore I must have a leak. Although likely to be true, it is not 100% accurate. The coil rusts when too much water or ice builds up on the coil over time. Ice can build up on the coil for other reasons, not just for leaks. Air flow has just as much impact on creating a frozen coil situation. Crushed ducts, poor design or dirty air York Air Conditionerfilters can all prevent enough warm air from flowing across the coil to prevent it from freezing. Proper maintenance and routine filter changes can help prevent frozen coils.
  2. My Capacitor is not swollen so it must be good. Not necessarily. A capacitor can be weak but not dead. A weak capacitor can wreak more havoc than a dead capacitor. Usually a dead capacitor will prevent the motor from running. Whereas a weak capacitor will allow the motor to run under poor conditions and quickly shorten the life of the motor. Motor replacements are expensive.
  3. A technician said a UV light would prevent dirt in my ducts. While a UV light helps prevent bacteria from growing on your coil, it does not prevent or destroy dust particles. Those pass the light unaffected and build up on motors and insulation that allows mold growth.
  4. I don’t need to maintain my heating or air conditioning system until it stops working. Although this is the choice most homeowners make, it is incorrect to assume the system will run fine without maintenance. Hidden dangers build up every year that a system goes without maintenance. Capacitors start to go weak (see item #2), compressors start to run hotter, drain lies build up with mildew. Delaying the maintenance will likely force the homeowner to spend more money on major repairs sooner than would be normal for a well maintained system. Maintenance does not guaranty your system will not need any repairs, but it does improve the life span of one of the most expensive systems in your home. You change the oil in your car every 3000 miles, why wouldn’t you have your system cleaned and inspected every year too.



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Are You at Risk of Carbon Monoxide Poisoning?


  • Have an older home?
  • Is your furnace over 20 years old?
  • Do you have a carbon monoxide detector?

Don’t be like one of our recent clients!!

After installing a carbon monoxide detector, it went off immediately that night. The gas company came and read 4 times the allowable limit in the house. That is a significant risk to life. All due to a hole in the furnace heat exchanger. This deadly situation was avoided when we replaced their 25 year old furnace, saving the family from a high probability of carbon monoxide poisoning or even death.

Don’t risk your family’s life.

Call Alexander Heating and Air Conditioning today for a furnace check up. We will inspect your heat exchanger and make sure it is safe for you and your family.

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