Wiser thermostat: Solid red for 1 second, once an hour
Battery low: replace the batteries soon.
Applies to: Wiser Radiator Thermostat. What you see: a light.
What Drayton Wiser says to do
- Fit 2 × 1.5 V AA (IEC LR6) alkaline batteries; Drayton says rechargeable batteries should not be used.
- After the change the thermostat calibrates itself on the valve. If it does not, twist the cap towards minus for a few seconds until the LED flashes blue and the motor starts.
Source
Drayton Wiser’s own help page, read on the date shown.
- Drayton Wiser: How to Change Batteries in Wiser's Smart Radiator Thermostat — Wiser Radiator Thermostat. wiser.draytoncontrols.co.uk Checked 2026-09-29.