Worcester Bosch
No call for heat from thermostat to boiler
Heating does not come on even when thermostat is set well above room temperature.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
RF link lost between thermostat and receiver, Faulty receiver relay, Broken BUS or switched live wiring, Thermostat in 'Off' or holiday mode
How to Fix / Troubleshooting
Safety first: Isolate mains before opening any receiver or wiring centre. Do not open the boiler casing.
- Check thermostat mode: Ensure it is in 'Heat' or 'Auto' mode, not 'Off' or 'Holiday'.
- Check RF/Wi‑Fi errors: Resolve any 'No RF' or communication errors first.
- Receiver status: Observe the receiver LEDs when the thermostat calls for heat. If no indicator changes, the signal may not be reaching the receiver.
- Wiring check: At the wiring centre, verify that the receiver's switched live output is correctly wired to the boiler's call‑for‑heat terminal.
- If wiring and signals are correct but boiler still off: The receiver relay or boiler control input may be faulty; a heating engineer should test and replace the receiver or interface.
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Repair Difficulty
Hard
4/5
Required Part
Worcester Bosch RF Receiver Module
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