E09
CTC Gas Valve Control Fault

Boiler displays E09; burner shuts down and will not restart until reset.

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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

Faulty gas valve coil, Loose gas valve connector, Faulty main PCB gas relay, Incorrect gas valve wiring

How to Fix / Troubleshooting

Safety: Turn off gas and power. Only a qualified gas technician should work on the gas valve and combustion system.

  • Check connectors: Remove the front cover and locate the gas valve on the CTC boiler. Ensure the electrical connector is fully engaged and free of corrosion or heat damage.
  • Visual inspection: Look for signs of water ingress or burning on the gas valve body and wiring.
  • Coil resistance (technician): With power off, disconnect the gas valve and measure coil resistance. Compare with CTC specifications. Replace the gas valve assembly if open or shorted.
  • PCB output (technician): During a call for heat, measure voltage at the gas valve connector. If no voltage is present and wiring is intact, the main PCB gas control circuit may be faulty and require replacement.
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Repair Difficulty

Professional Required 5/5

Required Part

Gas Valve Assembly
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