If you’re looking to replace the battery in a Honeywell thermostat, it’s a simple procedure.
You change the battery in a Honeywell thermostat by removing the cover plate, sliding out the battery compartment, replacing the battery, re-inserting the compartment, and putting the cover back on.
I’ll show you how to do it in more detail below. I’ve also included extracts from the manuals of a few selected series.
Honeywell Thermostats
There are two types of Honeywell thermostats: programmable and non-programmable.
Programmable thermostats have a touchpad to control and set the temperature and an LED screen that gives temperature readouts.
The procedure below applies mainly to the programmable type. I’ve covered the other type where it’s mentioned as applying to the non-programmable type. There are also various models, but the procedure is the same.
Replacing the Battery in a Honeywell Thermostat
Only six steps are involved to replace the battery in a Honeywell thermostat.
Step 1: Switch Off the Thermostat
Whichever thermostat you have, you will have first to switch it off.
For additional safety, you can disconnect the main (non-battery) power source or switch off the circuit breaker.
Step 2: Remove the Cover
Once the thermostat is switched off, proceed to remove its cover plate.
Hold the baseplate and gently pull from the lower corner, an outer edge to loosen it. Carefully separate the cover from the rest of the thermostat.
If it’s non-programmable, you may have to poke your finger underneath the plastic ring and gently pull it toward you.
If it has a decorative cover plate, turn off the electricity before removing it. Then use a screwdriver to unscrew it. There might be two screws, one each at the top and bottom.
Step 3: Slide Out the Battery Compartment
The battery compartment is normally located on one of the thermostat’s sides.
It should easily slide out. If not, you may need to push a tab on the top of the thermostat to release a latch holding the compartment.
Step 4: Replace the Batteries
The battery compartment may contain two or three AAA batteries.
Either one or both of them might be weak. Unless you know how to test their charge, it’s better to replace both of them.
When you’ve removed the old batteries, insert the new ones. But note the positive and negative polarities. It’s important to insert the batteries the right way.
Step 5: Reinsert the Battery Compartment
Once you’ve inserted the new batteries in the battery compartment, slide them back into place.
This time, however, insert it bottom first. Then gently push it until it snaps into place.
Step 6: Put the Cover Back On
You can finally put the cover plate back on after inserting the new batteries and reinserting the battery compartment.
Your Honeywell thermostat is now equipped with fresh batteries and ready to be turned back on to resume operation.
Variant Models
Although the procedure to replace the batteries in a Honeywell thermostat is similar across all models, I’ve mentioned some variant models below to note some peculiarities.
8000 Series
The models in the 8000 series include TH8110U, TH8320U, and TH8321U.
This advanced series of programmable Honeywell thermostats have several features, including WiFi compatibility. The above procedure applies exactly to this type.
The extract below is from the manual for the TH8321U model.
6000 Series
The models in the 6000 series include TH6110D, TH6220D, and TH6320U.
The battery compartment slides out from the side.
The extract below is from the manual for the TH6320U model.
5000 Series
The models in the 5000 series include TH5110D, TH5220D, and TH5320U.
You don’t have to remove the cover plate if you have this type. Skip this step and go straight to sliding out of the battery compartment.
The extract below is from the manual for the TH5320U model.
4000 Series
The models in the 4000 series include TH4210D and TH4110D.
They have a built-in compressor protection system.
It’s best to turn off the thermostat completely by switching off the circuit breaker. To remove the cover plate, push it from the bottom.
The extract below is from the manual for the TH4210D model.
3000 Series
The models in the 3000 series include TH3110D and TH3210D.
Like in the 4000 series, they have a built-in compressor protection system.
You might only need to replace the batteries in them once a year. When you do, turn off the thermostat completely by switching off the circuit breaker.
The extract below is from the manual for the TH3210D model.
2000 Series
The models in the 2000 series include TH1100DV, TH1110DV, TH1210DV, TH2110DV, and TH2210DV.
These are Honeywell’s budget thermostats. They must be switched off completely first before replacing the batteries. They take 2 AA batteries.
The extract below is from the manual for the TH2210D model.
Other Models
Honeywell also produces other models outside the above series. Two of them are:
Non-programmable models (e.g., RTH110B, RTH111B) – The batteries in them are generally simpler to replace.
Lyric Round (RCH9310WF) – This model has geofencing to control temperature based on your location. Switch it off completely before replacing its batteries.
The extract below is from the manual for the CM707 model.
Thermostat Batteries
Purpose and Lifespan
The batteries in thermostats help to retain settings in the event of power outages.
However, some only serve as backup power, so you might worry about changing them.
Most thermostat batteries usually last at lightest 8 months, but if it’s a Honeywell Thermostat, it may last up to a year.
Early Warnings
An indicator light on the thermal show may show if the battery level is low.
If so, you usually have around 6 to 8 weeks to replace the battery.
If the replacement due date gets closer, and you haven’t replaced the battery, you might get another warning screen before the thermostat stops working.
Video References
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