E04
Heatrae Sadia
Control PCB Fault / Internal Electronics Error
Heatrae Sadia electric water heater displays E04 and will not operate.
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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
Failed control PCB, Power surge damage, Moisture ingress on PCB, Loose or corroded PCB connectors
How to Fix / Troubleshooting
Safety first: Turn off the power at the main isolator and verify with a tester. Do not touch the PCB with power applied.
Steps to address E04:
- 1. Power reset: Leave the unit powered off for at least 5 minutes to allow capacitors to discharge. Restore power and see if the error clears. Transient faults can sometimes be reset this way.
- 2. Inspect PCB area: Remove the cover and visually inspect the control PCB. Look for burn marks, swollen components, or signs of water ingress. Check that all multi-pin connectors are fully seated.
- 3. Check for moisture: If there is condensation or water inside the control compartment, identify and correct the source (e.g. leaking pipework, failed grommets). Dry the area thoroughly before re-energising.
- 4. Verify supply voltage: Have a competent person confirm that the supply voltage and polarity are correct and stable. Overvoltage or incorrect wiring can damage the PCB.
- 5. Replace PCB: If E04 persists and visible PCB damage is present, the control board will usually need replacement with the correct Heatrae Sadia PCB. This should be done by a qualified technician due to live parts and configuration requirements.
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Repair Difficulty
Professional Required
5/5
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