Boiler shows A15, burner stops, may indicate return sensor fault

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

Defective return NTC sensor, Wiring damage, Poor thermal contact with pipe

Safety: Allow pipes to cool before handling sensors.

Check sensor mounting: Ensure the return NTC is firmly clipped to the return pipe or inserted in its pocket with thermal paste if specified.
Inspect cable: Look for cuts, abrasions, or signs of overheating along the sensor cable.
Connector check: Reseat the connector on the main PCB.
If the fault persists, replace the return NTC sensor with a Hoval-approved part.

Medium 3/5

Return Temperature Sensor (NTC)

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