ACV
DHW Priority / Diverter Fault
Boiler does not produce hot water but heating works normally (combi or system with tank-in-tank)
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
Faulty diverter valve motor, Stuck diverter valve, Faulty DHW flow sensor, Faulty cylinder thermostat (on tank-in-tank)
How to Fix / Troubleshooting
Safety first: Water may be cold; no special hazard beyond normal plumbing.
- Check DHW demand: On ACV combi models, open a hot tap fully and see if the boiler display shows a DHW demand symbol. If not, the flow sensor may be faulty.
- Check cylinder stat (storage models): Ensure the cylinder thermostat is set correctly and calling for heat.
- Listen for diverter movement: When switching between heating and hot water, you may hear the diverter valve motor. Silence may indicate failure.
- Professional repair: A technician should test and replace the diverter valve actuator, DHW flow sensor, or cylinder thermostat as needed.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
Diverter Valve Actuator
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements