A17
Wolf Return Temperature Too High / Delta-T Too Low

Boiler shows A17, burner stops, error appears after long run time

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

Oversized pump speed causing low temperature drop, Bypass valve stuck open, System incorrectly balanced, Plate heat exchanger scaled on DHW side

How to Fix / Troubleshooting

Safety: Turn off power before adjusting pump settings or valves.

  • Check pump speed setting: If the pump has adjustable speeds, set it according to Wolf’s recommendations (often medium rather than maximum).
  • Verify bypass valve: Ensure any automatic bypass valve is correctly set and not fully open, which can cause short-circuiting of flow.
  • System balancing: Have a heating engineer balance radiators and circuits to achieve proper temperature drop across the system.
  • Technician inspection: For DHW issues, a professional may need to descale or replace the plate heat exchanger.
Advertisements

Repair Difficulty

Hard 4/5

Required Part

Automatic Bypass Valve
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements