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Troubleshooting
9
If you have difficulty with your Thermostat, try these suggestions.
Most problems can be corrected quickly and easily.
All models
Screen is blank
Thermostat shows
Thermostat shows
+
Thermostat shows
but the boiler
does not switch on.
Heating system
does not respond to
temperature adjust-
ments.
Thermostat shows
+
+
Replace the batteries (T3 & T3R only).
Check the OpenTherm boiler has power (T3M only).
Contact installer.
Batteries have less than 10% power and need to be replaced
soon.
Batteries are critically low and need to be replaced
immediately - see 'Changing the Batteries'.
The boiler cycles on and off as it controls the temperature,
and sometimes the
has cycled off.
If the boiler doesn't switch on after a long period of time
contact your installer.
Make sure the set temperature is higher than the actual room
temperature.
Check the heating system is powered on.
Check the Receiver Box is powered and the Thermostat has a
wireless signal (T3R only).
The temperature sensor of your Thermostat is faulty,
contact your installer to repair or replace the Thermostat.
Boiler service reminder (UK Only). The boiler is due to be
serviced. Please contact your landlord or local housing authority.
20
icon will be displayed when the boiler
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Need help?
Do you have a question about the T3 and is the answer not in the manual?
Questions and answers
The alert triangle only is flashing on our new T3R wireless programmable thermostat. Why?
The alert triangle is flashing on the Honeywell T3R wireless programmable thermostat because the thermostat has likely lost its wireless connection (binding) with the receiver unit. This can be identified by a red flashing light on the receiver unit and either no wireless symbol on the thermostat display or a flashing wireless symbol with the warning triangle. Re-binding the thermostat and receiver unit is required to restore the connection.
This answer is automatically generated
I’ve changed batteries but no display showing
If there is no display on your Honeywell T3 thermostat after changing the batteries, ensure that you have used 2 new 1.5V LR6 AA alkaline batteries as required. Check that the batteries are correctly inserted with the correct polarity. If the problem persists, the thermostat might need a reset or could have a hardware issue.
This answer is automatically generated
Nothing appears on screen but flashing 19 and year
@Eric Stanley Britt
Where is the battery compartment
The battery compartment on the Honeywell T3 is located behind the front case. To access it, lift up the front case, then slide down the section with two small bumps to remove the batteries.
This answer is automatically generated