Thermostat not calling for heat: wiring, batteries and placement
The boiler only fires when something tells it to. A thermostat with flat batteries, a lost wireless link or a poor position quietly stops that instruction ever arriving.
What is actually going on with a thermostat that is not calling for heat
Wireless models pair to a receiver near the boiler, and the pairing is lost by battery changes and power cuts. Wired models fail at the terminal block or where cable has been nicked. Placement matters too: a thermostat above a radiator or in a draughty hall reads the wrong temperature and satisfies early, leaving the house cold while the control insists it is warm.
Things worth knowing about a thermostat that is not calling for heat
- Turn the set point well above room temperature when testing
- Listen for the receiver relay clicking near the boiler
- Thermostats over radiators or in draughts read badly
- Smart controls can lose demand when the hub is offline
- TRVs and a room stat in the same room fight each other
Where we deal with this
Who should undertake the work
- Gas appliance work must be completed by a suitably qualified Gas Safe engineer
- Oil appliance work should be completed by a suitably qualified OFTEC technician
- Jamie Crawford Heating states both Gas Safe and OFTEC registration
Sorted quickly: a thermostat that is not calling for heat
Our advice: Prove the demand first. Half of all no-heat calls are controls, not combustion.
Jamie Crawford Heating is based at 24 Bristol Road, Radstock, BA3 3EE.
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Services that cover this
Questions we get asked
- Should I hear a click when I turn it up?
- On most systems, yes — the receiver or wiring centre relay clicks. No click points at the control, not the boiler.
- Where should the thermostat go?
- An internal wall in a frequently used room, around 1.5m high, away from radiators, sunlight and draughts.
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