E9
Salus Hardware Protection / Short-Circuit Detected

Thermostat displays E9 and refuses to operate; may occur after incorrect wiring or short circuit.

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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

Short between output terminals (COM/NO/NC), Miswired live and neutral causing internal fault, Shorted external sensor to mains, Damage to protective components on PCB

How to Fix / Troubleshooting

Safety first: Isolate mains power at the consumer unit before inspecting wiring. Verify with a tester that circuits are dead.

Steps to check:

  • Inspect wiring: Remove the thermostat or receiver front and carefully inspect all terminals. Look for bridged conductors, stray copper strands, or incorrect links between live and switched outputs.
  • Check external devices: Disconnect the load (boiler, valve, pump) from the thermostat output terminals. Restore power and see if E9 clears. If it does, the fault lies in the external wiring or device.
  • Test for shorts: With power off, use a multimeter to check resistance between COM and NO/NC, and between these and neutral/earth. Very low resistance where none should exist indicates a wiring short.
  • Correct wiring: Re-terminate any damaged or incorrectly wired conductors according to the Salus installation diagram for your model.

Resolution: If E9 remains with all external wiring removed, the internal protection circuitry or tracks are damaged. Replace the thermostat or receiver unit.

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Repair Difficulty

Hard 4/5

Required Part

Salus thermostat/receiver main PCB
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