A10
Fondital Flow/Return NTC Sensor Fault

Boiler shows A10, heating temperature reading is incorrect or fluctuates rapidly

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

Open or short-circuited flow NTC sensor, Damaged sensor cable on Fondital boiler, Poor contact at NTC connector on PCB, Water ingress into sensor pocket

How to Fix / Troubleshooting

Safety: Turn off power before any inspection. Do not remove covers requiring tools.

User checks:

  • Reset: Reset the boiler once. If A10 reappears, a sensor or wiring fault is likely.
  • Visual check: Look for obvious damage to external sensor cables (if visible) without removing panels.

Technician actions:

  • Measure resistance of the flow and return NTC sensors at various temperatures.
  • Inspect and replace damaged NTC wiring harness or connectors.
  • Check for leaks around the sensor pockets and repair if necessary.
  • Verify the main PCB sensor input circuits.
Advertisements

Repair Difficulty

Medium 3/5

Required Part

Flow NTC Sensor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements