Remeha No CH output

Boiler provides hot water but no central heating on a combi or system boiler

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.

Possible Causes

Room thermostat not calling for heat, Faulty diverter valve stuck in DHW position, Motorised zone valve failure, Pump not running for CH

Safety first: Some checks involve live controls; only competent persons should perform them.

Check thermostat and programmer: Ensure heating is turned on and the set temperature is above room temperature.
Feel flow pipe: When CH is demanded, the flow pipe from the boiler should get hot. If not, the boiler may not be receiving a CH demand.
Engineer tasks: Test diverter valve operation, check external motorised valves (on system/regular boilers), verify pump operation on CH, and confirm correct control wiring.

Medium 3/5

Diverter Valve

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