The Effortless Guide To Honeywell Thermostat Battery Replacement

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Working a full-time job and reviewing tech in my free time tends to tire me out.

I decided to take a well-deserved break and nap one summer afternoon.

I couldn’t get comfortable enough to nap, and I realized I was covered in sweat.

Being the Smart Home nerd that I was, I’d set up my Honeywell Thermostat without a C-wire to take care of this sort of thing so I wouldn’t have to. I went over to check it out. The display was blank.

My first instinct was that the thermostat was broken, and I’d have to go through the hassle of getting it replaced, but I calmed down and thought about the situation analytically.

I hopped on the Web to do some research and try out some troubleshooting tips.

Turns out the batteries just needed replacing. I decided to compile an extensive Battery Replacement Guide for Honeywell Thermostat.

To Replace yourHoneywell Thermostat's Batteries, cut off power to the device and slowly pull the cover plate, which sits on top of the base plate. Gently force the batteries out of the compartment, and push in a new set of batteries into the slot, maintaining correct polarity. Refit the cover plate onto the base plate and turn on your device.

Find the Model Number of your Honeywell Thermostat

Checking your thermostat model number is crucial before any form of replacement or repair.

Honeywell thermostat models are named with the letters TH, T, RTH, RCHT, CT, TL, or RLV.

All models start their names with these letters.

The task at hand is to find out the model name in the easiest way possible.

You can simply check for your thermostat model name in your product ID or the user manual provided to you while purchasing the device.

But If you do not have the ID with you or somehow if you have lost it, all you need to do is gently pull off the base plate or wall plate.

Usually, the wall-plate comes off easily after a few tugs. If you’re worried about damaging it, get help from an HVAC professional.

Once you pull off the wall plate, just flip it over so you can see the other side of your device.

You will be able to find the model number printed on the back. Make sure you find your device name with the starting letters that were mentioned earlier.

Now before you even think about replacing your batteries, make sure your device is battery-operated.

Here is a description of all Honeywell thermostats with all the details which might come in handy during future repairs or replacements.

All battery replacement techniques are described below based on your Honeywell thermostat model.

Different models have their battery compartments in different spots. So this difference might be a bit confusing when you are trying to fix one.

Also, the battery type that is being used may vary based on your thermostat model.

Batteries could be AA or AAA or even lithium-ion type. This can also be a bit hard to take care of if you are working on a new device.

You have nothing to worry about. All issues related to battery replacement will be thoroughly covered by the end of this article, irrespective of the battery compartment space or the battery type.

Battery Replacement for the 1000 and 2000 models

These are the very basic thermostat models introduced by Honeywell. This series mainly has non-programmable models for the budget-minded.

The models in this series include TH1100D1001, TH1110D1000, TH1210D1008, TH2110D1009, and TH2210D1007.

Here is what you have to do to replace the batteries for these models:

• Turn off the supply to your thermostat before replacing your battery. Sudden interruption or sudden change in work patterns could harm the proper working of the device in the future.
• Examine your cover-plate for removal. You can either pull it using your thumb, index, and a middle finger placed either at the top and bottom or sideways. Or else you might have to twist or wiggle the base plate a bit and make sure it comes out correctly.
• Once the cover-plates are off, we are ready to find the battery compartment or slot and replace the AAA batteries with new ones. The polarities of batteries should be taken care of while replacing.
• Place the cover-plate back onto the base-plate and make sure it is intact.
• Now turn on the device supply, and you are all set to go.

Battery Replacement for the 3000 models

These are advertised as precision and high-reliability thermostats with built-in compressor aids.

What accounts for their reliability is the capacity to withstand sudden voltage fluctuation in the AC supply.

The models under the 3000 series are TH3110D1008 and TH3210D1004.

Here is what you do to replace their batteries:

• Turn off your thermostats for smooth revival
• Slightly twist and pull the bottom edge of your thermostat to remove the cover-plate without causing any damage to the contact points between the base-plate and the cover-plate.
• Gently pull out the batteries from the slots and replace them with the new ones you have. Take care of the polarities while replacement to assure proper working.
• Slowly and carefully slide the cover-plate to attach it back to the base-plate.
• You are so ready to turn back your supply and resume your room conditioning.

Battery Replacement for the 4000 models

The 4000 series models are well-planned updates of the 3000 models with programmable control and a better backlight that provides an excellent display.

Along with the already existing compressor protection system, it provides two heat stages.

The models under the 4000 series include TH4210D and TH4110D

Coming to the battery replacement procedure, In this model, the device provides a low battery indication for the user, which is very beneficial in our case as you now know when and how to act.

Here is how it is done:

• Cut off the supply that powers your thermostat to avoid any future malfunction.
• Keep your fingers on the bottom end of the cover plate and pull, not forcefully but in a way that would not cause any damage to the base-plate contact.
• You will find two AA-type batteries in the slot. Replace those with the new ones you have. Do not forget the battery type “AA”. Do check the polarities as well.
• Place the cover-plate back to its original position by sliding it onto the base-plate.
• You can now turn on those supply lines to power your thermostat.

Battery Replacement for the 5000 models

The 5000 series models are dual-powered; they may be battery or line-powered.

They also come with a new and efficient way to access the battery. You can now easily replace the batteries through the brand-new flip-out doors that guard the battery compartment.

The models under the 5000 series include TH5110D, TH5320U and TH5220D

The entire task related to unnecessary removal and reassembly of our device is now history.

From now on, you will be finishing your work in less than a minute. Here is what you do:

• Disconnect your thermostat from the supply electrically.
• The flip-door can be found at the top-right end. Pull the compartment out after firmly holding the cover-plate.
• Take out the AA batteries and make sure new ones go in smoothly.
• Check for polarity matching before you bring back the flip-doors to their normal state.
• Place the cover-plate back to where it belonged.
• Turn on your device and let the cooling progress.

Battery Replacement for the 6000 models

Honeywell has provided upgrades related to the control scheme of the device. The 6000 models come with a broader display.

The notable features include program schedules with presets that can help you save a few bucks.

The models under the 6000 series include TH6110D, TH6220D and TH6320U

Our job is getting easier after each upgrade. The 6000 series models have a proper sliding compartment for batteries, just like the ones we have in a clock.

Coming to our task, here is what you do:

• Turn off the supply to your thermostat.
• Replace the batteries from the compartment by accessing the sliding contacts.
• Make sure you use AA types.
• Refit the cover-plate which you had opened out earlier.
• Wiggle the cover-plate and make sure it is intact with the base-plate contacts.
• All set to go, you can now turn on your supply and start scheduling cooling patterns.

Battery Replacement for the 8000 models

The 8000 series models have loads of changes when compared to their predecessors.

Change can be seen both in the hardware and software that has heightened the ease of use of the device, and so has the brand new touch screen with refined backlights under the display.

The model also offers an application that syncs well with the device when in operation.

The 8000 Series models include TH8110U, TH8320U, TH8321U, and TH8320R1003.

Here is what you do with those AAA types that you have to rekindle your device:

• Turn off your thermostat and make sure you do not lead the device to any state of malfunction.
• Pull out the cover plate from the base-plate smoothly.
• You will find the battery compartment. Now replace the worn-out old AAA types with the newbies with matching polarities.
• Place the cover-plate back onto the base-plate and keep it intact.
• Yes, now you are all set to turn the device on

Battery Replacement for the Lyric Round

The Round Smart Thermostat is one of the higher-end thermostats available on the market, packed with features.

Apart from the basic air conditioning offered, it is smart enough to send you alerts regarding when you need to change your air filter and start air conditioning when you get back home, thus timing all events and saving a lot.

It is operated with the Honeywell Home app and is also supported by many third-party applications like SmartThings, Apple Homekit, etc.

Here is what you do to replace the batteries:

• Switch off the supply to your thermostat
• Separate the main body of your device from its sub-base.
• Replace the old batteries with new AAA-type batteries.
• Make sure you keep an eye on the polarity while replacing the battery.
• Keep the face-plate right on top of the sub-base.
• You are good to go now. Turn on your device and check for alerts on your Home app.

Battery Replacement for the HCW80

The device comes as a preconfigured set consisting of the HCW80(room unit) and the HC60NG( the relay module). It is powered using a pair of AA-type batteries.

The room unit can communicate with the relay module via wireless communication protocols.

This model is used widely in industrial blocks like malls, car showrooms, etc.

The unit provides a low battery indication by turning on a red LED. Once there is such an indication, the batteries ought to be changed.

Here is how it is done:

• Turn off the supply to your thermostat.
• Pull out the cover plate from the base-plate without causing any damage to the plate interconnects.
• You will find the AA-type battery slot. Replace the old ones with two 1.5 V units.
• Make sure that the polarities match and that the batteries fall into the slots properly.
• Now gently push the cover-plate back onto the base-plate and make sure it falls intact.
• You can turn on your device and check its operation.

Battery Replacement for the RTH110B

This is another non-programmable thermostat. One of its key features is the thermometer available that ensures precise temperature control with minimal temperature fluctuations.

There is a low battery indicative icon that pops up when the batteries are almost about to die. The unit uses AA-type batteries.

To replace the old ones that are dead:

• Turn off the thermostat.
• Pull out the cover plate using your thumb, index, and middle finger. Try wiggling sideways while pulling.
• Replace the old dead ones with new AA-type batteries.
• Make sure you place it correctly in the battery slots maintaining the correct polarity.
• Now you can place the cover plate back to the base-plate unit.
• Turn on the device, and you are good to go.

Some Things To Remember While Replacing Your Honeywell Thermostat Battery

People face a common issue while replacing batteries – breaking the delicate plastic parts by forcing them in or out.

The contacts between the cover plate and base plate are especially fragile.

Gluing broken plastic back together is a pain, so take extra care while replacing the batteries.

Also, be careful and ensure your device is not connected to a live wire while you mess with it.

This can damage your device due to surge voltage or arc formation at contacts.

You could even give yourself an electric shock if you aren’t careful. To be on the safe side, Cut off power to the thermostat before trying to get at its insides.

It’s also possible that your Honeywell Thermostat stops working after you change the batteries.

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Frequently Asked Questions

What battery do I need for a Honeywell thermostat?

Most new models use AA-type batteries. A few models use AAA type as well.

You can easily find the battery type in your device manual.

Or simply check the existing ones when you are trying to replace those. You could check this out for all product-related details.

How do I know if my thermostat needs a new battery?

You will get a low battery notification in the form of blinking icons on the screen, LED warnings.

The latest models with access to the Home app will send alerts on your Home hub.

Otherwise, you will find that the device is dead, and you can replace the batteries with new ones as described in the article.

Will a Honeywell thermostat work without a battery?

The power source for your thermostat depends on your model. All programmable thermostats are battery-operated usually.

Some of the non-programmable ones are also battery-powered. A few others get their share of power from the mains. It all pinpoints to the model you use.

When should I replace my Honeywell thermostat battery?

Ideally, just at the moment, you see the low battery indication. This might vary based on your thermostat model.

On average, you can go 8-12 months before having to replace the batteries.

Why does my Honeywell Thermostat not work even after replacing the battery?

There could be a couple of potential culprits. For a start, check if the batteries are correctly placed in the compartment or slot.

The latest thermostat models will notify you of the commonly occurring issues.

I would recommend you to get some professional assistance in case you still cannot operate your thermostat.