Vokera No Central Heating Demand / Diverter Valve Stuck

Boiler provides hot water but central heating does not come on, even though thermostat is calling

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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

Stuck diverter valve in DHW position, Faulty room thermostat or wiring, Faulty PCB CH demand input, Motorised diverter head failure

How to Fix / Troubleshooting

Safety first: Isolate power before accessing wiring or valve motors.

  • Check controls: Ensure programmer is set to heating on and room thermostat is turned up.
  • Boiler display: Check if the boiler shows a CH demand symbol; if not, the control circuit may be faulty.
  • Engineer tasks:
    • Test room thermostat and wiring continuity.
    • Check diverter valve motor operation and replace motor head if failed.
    • Free or replace the diverter valve cartridge if mechanically stuck.

Some Vokera models allow replacement of the diverter motor without draining; refer to the service manual.

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Repair Difficulty

Hard 4/5

Required Part

Diverter Valve Motor
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