Central heat and air thermostat question?
Question:We had central heat and air installed in our very old house only a few months ago. The thermostat, a square digital faced one, is on our kitchen wall. It, of course, has the room temp. read out and in the upper left corner has the outside temp. readout also. Both of these areas are blank this morning. We changed the back-up AA batterties and it brought up the room temp. on it's face for a while, but now both areas are blank again. We obviously could not run the ac even if we wanted to if it can't sense the room temp. Any suggestions? We called the installer and of course get an answering service. With it being a 3 day holiday weekend, doubt he'll call back before Tuesday. Just wondered if anyone knows anything about digital thermostats?
Answers:
The thermostat batteries do not run the system, they only serve to provided the needed electricity to maintain the stored memory of the thermostat's pre-programmed instructions of temperature, offsets, time of day, etc.
The thermostat gets its electrical power from the HVAC system. The typical thermostat controls the HVAC system with low voltage, for safety, so the HVAC system has a little transformer, that transforms the electrical power to about 24 volts, too little to shock anybody, or cause a spark that could ignite anything.
Try turning the "FAN" switch to "ON". If the blower starts, the 24 volts is OK, and if it is, then you may have a bad thermostat. If the blower does not start, then you may have a bad 24 volt transformer, or a wiring problem to or from the transformer as it makes its way to the thermostat.
If it is the thermostat, a replacement can be purchased from any good hardware or home building store for around $30. They are not that difficult to install because the wires are color coded. You will either have to know what type of system you have, like a "heat pump", or "oil burner" system, etc., or you can take the old thermostat with you and the employees at the store can sell you a suitable replacement.
Good luck and stay warm/cold, whichever.
Do you have the manual? Look it up in there; try turning the entire system on / off again, to reset it. If not, there might be an issue with the unit itself, not the thermostat, since you have replaced the batteries. Try calling the manufacturer of the unit.or else contact the installer's emergency number. It's a holiday weekend and hot, you have a simple question. They should have the time if they are a quality company.
Sounds like you may have lost power to the furnace . Go to breaker box and look for any tripped circuits. It should be marked as furnace. turn it of firmly and wait 30 seconds then firmly reset it. see if the thermostat is now powered.
Everything your going through was exactly the scenario at my house few months ago.
There were a few wires in the back of the digital reader that some-how came loose. You need to know which color goes where, so don't just plug anything were ever you THINK it goes. My grandfather was able to figure out what went where, so if you find someone at home-depot or something they might be able to reconnect those wires.
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