Why does my thermostat say low battery?

Asked By: Erola Wrassmann | Last Updated: 18th June, 2020
Category: home and garden smart home
4.2/5 (1,734 Views . 14 Votes)
Most models of programmable thermostats will display or flash some sort of low battery symbol when the batteries begin to run low. At this point, the thermostat can no longer control the HVAC system. This could possibly lead to excessive heating or cooling of your home, or no heating or cooling at all.

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In this regard, how do you reset a low battery on a Honeywell thermostat?

How to Reset a Honeywell Programmable Thermostat

  1. Set the thermostat switch to "Off."
  2. Insert a coin into the slot on the battery door to push it open.
  3. Remove the batteries.
  4. Insert the batteries backward, so that the negative pole lines up with the positive terminal.
  5. Remove the batteries and put them back in the correct way, then close the battery door.

Also, how do I know if my thermostat battery is bad? 4 signs your thermostat is bad

  1. Sign #1: Your thermostat has no power or is unresponsive.
  2. Sign #2: Your heater or A/C won't turn ON.
  3. Sign #3: Your A/C or heater runs constantly and won't turn OFF.
  4. Sign #4: Room temperature and setting don't match.
  5. Step #1: Make sure thermostat is on the right setting.

Beside above, why Does My Honeywell thermostat say low battery?

If your Honeywell thermostat has an LED display, and it needs batteries, it usually has a low battery warning. This warning appears on the screen as a flashing banner that says "Replace Battery" or "Batt Lo." If you ignore this, a blank screen is your last warning before the thermostat stops functioning.

How do I change the battery in my thermostat?

To remove and replace the batteries, pull at the bottom of the thermostat to remove it from the wallplate. Once removed, turn the thermostat over and insert 2 fresh AA batteries, and then reinstall the thermostat on the wallplate.

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Does low battery affect thermostat?

This could possibly lead to excessive heating or cooling of your home, or no heating or cooling at all. In general, batteries help to retain thermostat settings during power outages. Low batteries in digital thermostats are a common cause of issues preventing the heating and cooling system in your home from running.

Can a low battery affect air conditioning?

A weak car battery can cause your auto air conditioner to function poorly or not at all. Car batteries need to have enough voltage to trigger the AC compressor, and while it may be strong enough to run the rest of your car, it may still be too weak to run your car's air conditioning. Bacteria Build-up.

What happens when thermostat battery dies?

The Batteries Are Dead
Some thermostats require battery power, and if the battery dies, your screen will go blank. But if the battery drains down, you'll see a blank thermostat screen (or possibly a blinking light) as it recharges. Once it's recharged itself, you'll be good to go.

Will a bad thermostat cause the AC not to work?

Under most circumstances, a bad thermostat will not have any effect whatsoever on the air conditioning system. Other than that, the AC system could care less what the engine is doing. The heater, however, is a different story. A car's heater core is like a second radiator.

How long do thermostat batteries last?


Some batteries can last as long as 5 years while others might not make it 3 months. Even if your thermostat is hardwired, it will probably have a back-up battery that will need to be periodically replaced. But don't be upset—the back-up battery allows your system to work even if there is a glitch in the power system.

How do I reset my thermostat?

Here are the steps you need to take to reset your AC thermostat.
  1. Shut Down Your AC at the Thermostat. The first step in resetting your AC thermostat is to turn it off at the AC unit.
  2. Find Your Circuit Breaker Box.
  3. Reset the Circuit Breaker for Your AC Unit.
  4. Wait 30 Seconds.
  5. Turn the AC Thermostat Back On.

How do I troubleshoot my Honeywell thermostat?

If your analog Honeywell thermostat is still not functioning correctly, try removing the door to the unit. Look for dust or debris and clean the unit off using a soft cloth. Another possible issue with an analog thermostat is its wiring. You should be able to see a series of colored wires within the thermostat box.

What model is my Honeywell thermostat?

Flip the thermostat itself over and look for the model number, which should be printed somewhere on the back of the case. Thermostat model numbers all begin with T," "TH," "RTH" "C," or "CT." Oftentimes, there will be a "Y" in front of the model number.

What does the battery in a thermostat do?

The battery of the thermostat keeps your programming saved and prevents your heating and cooling control system from turning off when the power goes out.

Is there a reset button on a Honeywell thermostat?


If you are having a Smart or Lyric Round Honeywell Thermostat then you need to press and hold the “cloud' icon. You will see an arrow down “↓” button then press that until you get a Reset option. Select “Reset”.

Why is my thermostat not working?

Here are four basic things to look at if your furnace isn't responding to your thermostat settings: Check the power source. Your thermostat may just not be connected right or at all. A blown fuse, tripped circuit breaker or dead batteries will prevent the thermostat from turning on your furnace.

How do I set my Honeywell thermostat to cool?

Press the "System" button to put the thermostat in Heat, Cool or Off mode. To change the setting, push the button again. The screen will display the setting you've selected. On the right side of the display, the up and down arrow buttons operate the temperature settings.

Do all thermostats have 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 replace an old thermostat?

Consider this your big picture guide through the process.
  1. Turn Off Power to A/C and Furnace.
  2. Remove Face of Old Thermostat.
  3. Take a Picture of the Wires.
  4. Disconnect Wires from Old Thermostat.
  5. Remove Old Mount.
  6. Put on the New Thermostat Mount and Connect Wires.
  7. Screw Faceplate Mount to Wall.
  8. Attach New Thermostat Face.

How do you know if your car thermostat is working?


Start your car's engine and allow it to idle. Look through the radiator filler neck to see if the coolant flows. At this time, it should not be flowing as your car has not reached the operating temperature to cause the thermostat to open. If you find the coolant is flowing, it means the thermostat valve is open.

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.

How do you troubleshoot a thermostat?

You can successfully troubleshoot a thermostat.
  1. Check the thermostat temperatures. There are two temperatures to take into consideration when dealing with a thermostat; set point temperature and room temperature.
  2. Calibrate your room temperature.
  3. Check the connections.
  4. Take the thermostat out of the equation.