05
Immergas Primary Return Temperature Sensor Fault (NTC Open/Short)

Error 05 displayed; unit may overheat quickly or shut down during operation.

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

Defective return NTC sensor, Loose or corroded NTC connector, Damaged wiring harness, Control board sensor input fault

How to Fix / Troubleshooting

Safety: Turn off power before removing covers.

  • Locate return NTC: The return NTC is typically mounted on the return pipe to the primary heat exchanger.
  • Check connections: Ensure the NTC is firmly clipped to the pipe and the connector is fully seated on the sensor and on the control board.
  • Inspect cable: Look for signs of overheating or mechanical damage along the cable route. Replace the harness if insulation is cracked or brittle.
  • Replace NTC if suspect: Swap in a genuine Immergas return NTC sensor. Ensure good thermal contact with the pipe.
  • Test: Restore power and demand hot water. If error 05 persists, the main PCB may require replacement.

Recommendation: Sensor diagnosis is relatively simple, but PCB replacement should be done by an authorized service center.

Advertisements

Repair Difficulty

Medium 3/5

Required Part

Primary Return NTC Sensor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements