Alpha
Diverter Valve Passing / Stuck Mid-Position
Radiators get hot when only hot water is being used (no heating demand set).
Advertisements
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.
Advertisements
Possible Causes
Worn diverter valve seals, Sticking diverter valve spindle, Debris in diverter valve, Faulty diverter motor head
How to Fix / Troubleshooting
Safety: Components may be hot; isolate power and allow to cool before working on the boiler.
- Confirm symptom: Turn heating off at the programmer and thermostat, then run a hot tap. If radiators warm up, the diverter valve is likely passing.
- Exercise valve (temporary): Switching between CH and DHW modes several times may temporarily free a sticking valve.
- Clean system: Sludge can cause valves to stick. A system flush and filter installation can help prevent recurrence.
- Replace diverter valve: Long-term resolution usually requires replacement of the diverter valve cartridge or complete assembly by an engineer.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Diverter Valve Assembly
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements