Ideal Diverter Valve Passing / Cross-Flow

Radiators get hot when only hot water is demanded on a combi 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

Worn diverter valve seals, Debris in diverter valve, Incorrect pipework connections, Sticking diverter motor

Safety first: Radiators may become unexpectedly hot; be cautious around them.

User checks:

Confirm behaviour: Turn central heating off at the programmer and thermostat, then run a hot tap. If radiators still warm up, the diverter valve is likely passing.

This fault requires a heating engineer to strip, clean, or replace the diverter valve assembly or motor head and check system pipework.

Hard 4/5

Diverter Valve Assembly

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