E20
IBC AC Supply / Low Voltage Fault

Boiler displays E20; may indicate low voltage or power supply issue.

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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

Incoming line voltage too low, Loose power connections, Shared circuit with heavy loads, Failing internal power supply on control board

How to Fix / Troubleshooting

Safety: Only qualified persons should work inside electrical panels. Turn off power at the breaker before tightening connections.

  • Check supply voltage: Verify the boiler is on a dedicated circuit with the correct voltage as specified by IBC.
  • Inspect power connections: At the boiler's terminal block, ensure line, neutral, and ground are tight and free of discoloration.
  • Reduce shared loads: If other large appliances share the circuit, move them to a different circuit.

If E20 continues with proper supply voltage, the internal power supply on the control board may be failing and should be replaced by a technician.

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Repair Difficulty

Hard 4/5

Required Part

Main Control Board
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