Furnace shows E07 and will not operate; may be accompanied by unusual temperature readings.

Safety: Isolate power before working on electrical connections.

• Locate the flow sensor: On Kospel furnaces, the flow NTC is usually clipped or screwed into the flow pipe leaving the heat exchanger.
• Inspect wiring and connector: Check the two-core cable from the sensor to the control board. Look for cuts, crushed insulation, or loose plugs. Reseat the connector on the PCB.
• Check sensor resistance (if you have a multimeter): With power off, disconnect the sensor and measure its resistance. Compare with the Kospel service chart (e.g., around 10 kΩ at 25°C). Infinite or near-zero resistance indicates a faulty sensor.
• Replace if faulty: If the sensor is out of range or physically damaged, replace it with a genuine Kospel flow NTC sensor of the same specification.

After replacement, clear the error by cycling power and verify normal operation.