Dead Batteries No power to thermostat could also be caused by old batteries. When it comes to the controls and display on your thermostat, these are typically powered by batteries. Over time, these will wear out and stop working. If it has been a while since you changed these batteries, this could be your problem.

How do I restore the power to my thermostat?

Here’s an easy four step process to resetting your thermostat after a power outage.

  1. Turn off your thermostat. Before doing any other troubleshooting, start by finding your thermostat and turning it off. …
  2. Locate and reset circuit breaker. …
  3. Wait 30 minutes. …
  4. Turn the thermostat back on.




Where does the thermostat get it’s power from?

voltage transformer

Source Power & Voltage Level for Room Thermostats. Most room thermostats on heating and cooling systems receive their 24V AC electrical power from a low voltage transformer that itself is usually found at the boiler or furnace (blue arrow in our photo at left).

Why am I not getting power to my Honeywell thermostat?

The easiest way to fix it is to reset your thermostat. Other common methods include replacing your batteries, checking your wiring, and cleaning the air filter associated with your Honeywell Thermostat.

Why my thermostat is blank?





If your thermostat is blank, the first thing you should do is check the batteries. Chances are, the batteries have died and the thermostat simply can’t power on. Replace the batteries and see if your thermostat turns on.

How do I know if my thermostat has power?

Test the Thermostat With a Multimeter

Touch one of the meter probes to the R terminal (to which the red wire is attached) and the other probe to the G, W or Y terminal and note the reading. If the thermostat has power, the reading should be between 22 and 26 volts.

Do thermostats run on batteries?

Many thermostats still use batteries, while others draw power from your home’s electrical or HVAC system. The typical battery-powered dial, switch, digital or programmable thermostat is going to take regular AA or AAA alkaline batteries, a button-style 3V lithium battery or a 9-volt battery.

How do I fix an unresponsive thermostat?



If the thermostat is still unresponsive, make sure the breaker is shut off and remove the cover. If it looks dirty inside, use canned air or a soft artist brush to clean away accumulated grime that may be affecting its functionality. Then look for issues like loose wiring or terminal screws and tighten them up.

Can a thermostat work without batteries?

Yes, the Smart Thermostat will work without batteries. If there are no batteries inserted, and the thermostat is running off solely of AC power, the thermostat will report a low battery (indicated by a caution sign and LOW BATTERY flashing on the display).

How do I know if my thermostat is broken?

The following are six signs that your thermostat is damaged or broken.

  1. Your HVAC System Won’t Turn on. …
  2. Your Air Conditioner or Heater Runs Non-Stop. …
  3. Differing Temperature Readings Throughout the Home. …
  4. Short-Cycling. …
  5. Programmed Settings Keep Getting Deleted. …
  6. There’s No Response to Changes in Temperature Settings.


How do you tell if you need a new thermostat in your house?

Signs You Need a New Thermostat

  1. Heating or cooling system will not turn off or on.
  2. The temperature reading is incorrect.
  3. Recent spike in your energy bill.
  4. Frequent temperature fluctuations.
  5. Thermostat is 10 years old or older.

How do you know if your thermostat needs new batteries?

The most obvious sign that you need to change your thermostat batteries is when the thermostat literally tells you the batteries are about to die! Most programmable models will now flash a low battery warning, usually about a month or two before the battery completely dies.

What happens when the thermostat goes out?



HVAC system won’t turn on: The most obvious sign of a bad thermostat is that the HVAC system in your building won’t turn on or respond to the thermostat. You should be able to turn on your heating or cooling system from the thermostat, or change operation back and forth from heating to cooling.

How do I test my thermostat?

Here’s how to test your thermostat to see if it works:

  1. With the power to the furnace off, remove the thermostat or thermostat cover to expose the wires. …
  2. Unscrew and remove the wires from their terminals. …
  3. Twist the bare ends of the two wires together. …
  4. Turn the power to the furnace back on.

Can you jump a thermostat?

Since the thermostat is basically a switch, you can bypass it just like you can bypass a wall switch, and if the furnace or air conditioner is working properly, it should come on.

What do you do when your Honeywell thermostat stops working?

First, head over to your electrical breaker box and turn off the power source to your thermostat. Next, turn the thermostat off and carefully remove the top cover of the unit. Look at the wiring and check if anything is loose, broken, or disconnected. Also, check to see if everything is clean.