Drayton Wiser radiator thermostat: what its lights mean

The Wiser Radiator Thermostat by Drayton has three small lights on its front. Red that shows for a second once an hour means the batteries are low; red flashing for five seconds every minute means they are critically low. Blue flashing is recalibration on the valve, and red flashes while you twist and hold the cap are the reset countdown.

The lights are on the front of the thermostat head; Drayton says to fit it with the LED facing forwards. This page covers only the Radiator Thermostat: the Wiser Room Thermostat and hub are in ‘Left out, and why’ on the thermostat hub page.

1. Solid red for 1 second, once an hour

   Battery low: replace the batteries soon.

   Wiser Radiator Thermostat. 2 steps from Drayton Wiser on its page.

2. Red flashing for 5 seconds every minute

   The batteries are critically low: replace them immediately. The Wiser Home app also sends a low-battery alert.

   Wiser Radiator Thermostat. 2 steps from Drayton Wiser on its page.

3. Blue flashing

   The thermostat is recalibrating on the valve: the motor drives briefly to find its position. It happens after a battery change, or when you twist the cap towards minus for a few seconds.

   Wiser Radiator Thermostat. Drayton Wiser gives no step for this.

4. Red flashing while you hold the cap at minus

   The thermostat has entered reset mode. Keep holding: after eight red flashes (about 20 seconds) the long press is complete.

   Wiser Radiator Thermostat. 1 step from Drayton Wiser on its page.

5. All three lights flash once

   Confirmation that the thermostat is factory resetting. It then reboots, ready to be paired again in the Wiser app.

   Wiser Radiator Thermostat. Drayton Wiser gives no step for this.

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