How to Replace the Batteries in Your tado° Smart Radiator Knob

Your tado° Smart Radiator Thermostat needs batteries to operate the valve on your radiator. When the batteries become too weak, the thermostat may no longer have enough power to close the radiator valve properly.

This is important: a low-battery tado° knob can result in a radiator continuing to heat even when the heating has been turned off. tado° itself confirms that insufficient battery power can prevent the Smart Radiator Thermostat from closing the radiator valve completely. (tado° Support)

How do you know that the batteries need replacing?

There are several signs to look out for.

1. The low-battery symbol appears

The tado° display will show a low-battery warning symbol when the batteries are running low. The tado° app can also indicate that a particular device needs new batteries. (tado° Support)

Do not wait until the batteries are completely empty. Replace them when the low-battery warning appears.

2. The radiator does not completely stop heating

Another practical warning sign is that you set the heating to OFF or turn the temperature down, but the radiator continues to warm up more than expected.

Remember that a radiator does not become cold immediately after the heating is switched off. The radiator and the water inside it are already hot and will need some time to cool down.

Also remember that the minimum temperature setting in your studio is 16°C. Setting the temperature to 16°C does not mean that the radiator will immediately become completely cold; the tado° thermostat will only request heat when the room temperature requires it.

However, if the radiator continues to heat noticeably after the heating has been switched off or the room is already above the target temperature, check the following:

• Can you hear water running through the radiator?
• Can you feel that hot water is still flowing through it?
• Does the radiator remain warm instead of gradually cooling down?

If you can hear or feel water continuing to circulate through the radiator when there should be no heat demand, the tado° knob may not have enough battery power to close the valve completely.

In that case, replace the batteries rather than simply turning the temperature setting up and down repeatedly.

How to replace the batteries

The procedure is straightforward and normally takes only a few minutes.

Step 1 — Remove the tado° knob

Hold the base of the tado° thermostat so that it does not move and carefully turn the thermostat body to remove it from the radiator valve.

Step 2 — Open the battery compartment

Open the battery compartment on the back of the tado° thermostat.

Step 3 — Remove the old batteries

Take out both batteries.

Wait approximately 10 seconds before inserting the new batteries. tado° recommends this to allow the device to reset correctly before the new batteries are installed. (tado° Support)

Step 4 — Insert two new batteries

The required batteries depend on the tado° hardware version:

• VA01: 2 × AA alkaline batteries (LR6)
• VA02: 2 × AA alkaline batteries (LR6), or the specifically recommended Panasonic Eneloop AA 2000 mAh NiMH rechargeable batteries
• tado° Smart Radiator Thermostat Basic: 2 × AA alkaline batteries (LR6), or the specified Panasonic Eneloop rechargeable batteries. (tado° Support)

The model number can be found near the pairing button on the device.

Important:

• Always replace both batteries at the same time.
• Do not mix old and new batteries.
• Do not mix different battery types.
• Make sure the + and – poles are positioned correctly according to the markings inside the battery compartment. (tado° Support)

Step 5 — Close the battery compartment

Close the battery compartment securely.

Wait about 1 minute before mounting the tado° thermostat back onto the radiator valve.

This waiting period allows the thermostat to initialise and calibrate correctly. (tado° Support)

Step 6 — Refit the tado° knob

Place the thermostat back onto its base and turn it until it is correctly secured.

The tado° thermostat will then calibrate the radiator valve.

Step 7 — Check that the radiator works correctly

After replacing the batteries, check that:

1. the tado° display works normally;
2. the low-battery warning has disappeared;
3. the thermostat responds to temperature changes;
4. when the heating is turned off, the radiator eventually stops receiving hot water.

Remember: give the radiator time to cool down. A warm radiator immediately after switching the heating off does not automatically indicate a problem.

A simple test if you are unsure

If you suspect that the tado° batteries are becoming weak:

1. Turn the heating off or set the room to its minimum temperature of 16°C.

2. Wait long enough for the radiator to start cooling.

3. Listen carefully.

If you can still hear water flowing through the radiator when there is no heating demand, and the radiator continues to heat rather than gradually cool down, check the tado° battery status and replace the batteries if necessary.

A low-battery thermostat may not have sufficient power to operate the valve correctly. tado° specifically warns that a Smart Radiator Thermostat with insufficient battery power can leave the radiator valve open, causing the radiator to continue heating. (tado° Support)

Watch the video

Here is a video showing how to replace the batteries in a tado° Smart Radiator Thermostat:

How to replace the batteries in the tado° Smart Radiator Thermostat

You can also use the video you provided as a practical reference: tado° battery replacement video

Please do not wait until the batteries are completely empty

Replacing the batteries when the warning first appears is the easiest way to avoid a radiator that keeps heating because the valve can no longer be operated properly.

A low-battery warning is not something to ignore — replace the batteries promptly. (tado° Support)