Thermostat Malfunction

My thermostat will not power on.

I tried changing the batteries and it still shows a malfunction

Here is my thermostat Screenshot by Lightshot

How can I fix this?

Malfunction indicates the device is having trouble communicating with the panel.

Steps on how to address a malfunction for a Z-Wave device like the TSTAT can be found here:

To confirm, after replacing with new batteries, in the correct orientation, the device does not power up at all?

It powered on, but would not work to produce heat or AC

After a day it powered down.

I get this error when trying to troubleshoot on the app Screenshot by Lightshot

Please help, thanks!

Currently the thermostat is in malfunction. To resolve:

  • Clear the TSTAT from the network.
  • Add it to the network
  • Run a Z-Wave Network Rediscovery

Currently the TSTAT is not connected to C-Wire meaning it only runs on battery. It is recommended to connect the TSTAT to C-Wire for power if possible.

Steps on how to clear and add Z-Wave devices from the network can be found here

More information on the T2000 including Installation and Programming can be found here

I tried to clear the device using Screenshot by Lightshot but it did not work

The device will not power on. How can I clear the device while pressing the down button if it will not power on or off?

I changed the batteries and now it works.

I changed them a few days ago with new batteries and it worked for 2 days and stopped working.

I changed the batteries again today with new batteries and now it is working.

How can I keep the thermostat working?

It is recommended to use C-Wire for power with battery as backup. If a C-Wire cannot be used, the batteries will drain faster.

Always make sure to use high quality batteries that are unused and within their printed date code when swapping batteries.

What is C-Wire

How can I check if this is installed?

A Common Wire, or C-Wire, carries 24v from the heating system (low voltage) to the TSTAT.

If you have one, you should have it running with the rest of the wires for your thermostat.

You can refer to the installation guide below to see how to connect the C-Wire to the TSTAT.

If you have a C-wire, but its not connected to the TSTAT, you will need to remove the TSTAT from the Z-Wave network and wire up the TSTAT. Then reconnect to the Z-Wave network. The TSTAT must be connected to C-Wire first before it is connected to the panel in order to incorporate the C-Wire.

Be sure to turn off all heating/cooling power (usually at the circuit breaker) before wiring the TSTAT.

I keep changing the double AA batteries and after 1 week is says battery low

Is there something wrong that is causing the batteries to drain so quickly?

In the past the batteries would be good for a few months, now after a week they are draining.

These are brand-new batteries from Duracell.


If running without C-Wire, the TSTAT will use the batteries more quickly.

Additionally, When Z-Wave communication is poor, the thermostat uses more power attempting to connect to the controller.

This thermostat should only be powered by 4 AA alkaline batteries .Always make sure the AA batteries are new and within their printed date code.

How do I know if the communication is poor?

Typically networks with no or too few repeating nodes will have communication issues. You’ll see slow to process commands, or commands that dont process.

You can see signal strength between the hub/devices at the panel in System Tests > Z-Wave Tests.

I am getting a thermostat malfunction error again - I tried to trouble shoot this and it did not work.

It said contact support - how can I fix this?

Make an adjustment from the device locally and wait a few moments for it to update in ADC. Otherwise you can power cycle the device. Either may update and clear out the malfunction.

If neither clears out the malfunction, you will need to clear the device from the network and re-add it to the network. Once re-added run a network rediscovery.

How do I power cycle?

Remove power, wait 30 seconds, re-add power. In the case of the thermostat, remove it from its baseplate, take out the batteries.

The thermostat is now working from the wall unit, but when I try to turn it on from the app or the IQ panel it does not work and shows a malfunction

The wall unit has the temperature displayed permanently and will not turn off - what is causing these issues?


I am still seeing a pairing date of 5/1/2021 for that thermostat on your account. Now that the thermostat is powered, to troubleshoot the communication malfunction it needs to be deleted and relearned.

When powered by AC, your Tstat can have its display on at all times. This is a setting.

  • In on the Thermostats card, click the arrow.
  • Click Advanced Configuration.
  • Click User.
  • In Display ON, select Enabled or Disabled as desired.
  • Click Save.