Chaffoteaux
No Central Heating Output
Boiler provides hot water but no central heating, even though the room thermostat is calling for heat.
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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
Room thermostat or programmer fault, Diverter valve stuck in DHW position, Pump not running, Faulty CH flow sensor (if fitted)
How to Fix / Troubleshooting
Safety first: Isolate power before accessing wiring or internal components.
User-level checks:
- Check that the heating program is set correctly and that the thermostat is turned up.
- Ensure any external motorised valves (if present) are in the correct position.
Technical checks (qualified personnel):
- Verify that the boiler receives a call for heat at its control terminals.
- Check diverter valve operation; if stuck in DHW, repair or replace.
- Confirm pump operation when CH is demanded.
- Test external controls and wiring for faults and replace defective components.
After repair, confirm that radiators heat up and that the boiler modulates correctly in CH mode.
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Repair Difficulty
Medium
3/5
Required Part
Room Thermostat Interface
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