E19
Roca NTC Sensor Short Circuit

Furnace shows sensor short-circuit error, often immediately at power-up

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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.

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Possible Causes

Shorted flow or return NTC, Sensor wires touching or pinched, Moisture bridging sensor terminals, Faulty PCB input

How to Fix / Troubleshooting

Safety first: Isolate power before testing sensors.

  • Identify which sensor: The display or service manual will indicate which NTC is affected (flow, return, DHW, flue).
  • Disconnect sensor: Unplug the suspected sensor from the PCB and power up briefly. If the code changes to open-circuit, the sensor is shorted.
  • Inspect cable: Look for crushed or melted insulation causing the two conductors to touch.
  • Replace sensor: Fit a new Roca NTC sensor of the correct type and re-test.

Warning: If a new sensor does not resolve the error, the PCB may be defective and should be replaced by a technician.

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Repair Difficulty

Medium 3/5

Required Part

Temperature NTC Sensor
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