Furnace displays E07; often linked to DHW sensor or DHW circuit issues on combi models.

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 DHW NTC, Loose sensor connection, Scale in DHW heat exchanger, Control board DHW input fault

Safety first: Isolate power and close DHW isolation valves.

Check DHW sensor: Locate the DHW NTC on the plate heat exchanger. Inspect wiring and reseat the connector.
Measure resistance: Test the sensor with a multimeter and compare to Sime data. Replace if faulty.
Consider descaling: If hot water is erratic and the sensor is good, the plate heat exchanger may be scaled and require professional descaling or replacement.

Medium 3/5

DHW NTC Temperature Sensor

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