Heater displays E17, often associated with sensor readings out of expected range.

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

NTC sensor short-circuit or open-circuit, Incorrect sensor type fitted to Baxi unit, Wiring harness damage, PCB analogue input failure

Safety: Isolate power before testing sensors.

Steps:

Identify which sensor: Refer to the Baxi manual; E17 may indicate a specific sensor (flow, return, DHW, or flue).
Check for shorts or breaks: Inspect the sensor cable for cuts, crushed sections, or exposed conductors.
Measure resistance: With a multimeter, check sensor resistance and compare to the Baxi chart. Replace if clearly out of range.

Professional: If sensors and wiring are good, the PCB likely needs replacement.

Hard 4/5

Relevant NTC Sensor

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