Heater displays H28; may be associated with sensor calibration or internal reference errors.

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

Out‑of‑range thermistor readings, Corrupted calibration data on PCB, Faulty reference voltage on PCB, Mixed non‑genuine sensors

Safety: Turn OFF power before working on sensors or PCB.

1. Reset unit: Power cycle and test again.
2. Verify all sensors are genuine: Ensure any previously replaced thermistors or sensors are Panasonic‑approved parts.
3. Inspect sensor wiring: Check all temperature sensor harnesses for damage or poor connections.
4. If multiple sensors show issues: The PCB's reference circuit or calibration may be faulty; replacement by an authorized technician is recommended.

Hard 4/5

Main Control PCB

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