Salus Stuck Relay / Permanent Call for Heat

Heating stays on constantly and does not turn off even when the thermostat is satisfied or turned down.

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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

Welded relay contacts in receiver, Miswired COM/NO/NC terminals, Boiler set to constant override mode, External link left in boiler thermostat terminals

How to Fix / Troubleshooting

Safety first: Turn off power to the boiler and receiver before inspecting wiring.

Steps to check:

  • Observe receiver LEDs: If the receiver's call-for-heat LED is off but the boiler is still running, the relay contacts may be welded closed.
  • Check wiring: Ensure the boiler's live feed is not accidentally wired directly to the call-for-heat terminal, bypassing the relay. Verify that only COM and NO are used for a normally open control.
  • Test relay: With power off, disconnect the boiler control wires from the receiver and measure continuity between COM and NO. There should be no continuity when the relay is off. If continuity is present, the relay is stuck.
  • Check boiler settings: Confirm that any internal boiler timer or override is set to accept external control and not forced ON.

Resolution: Replace the Salus receiver if the relay is stuck. Correct any wiring errors and remove any factory links in the boiler thermostat terminals if required.

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Repair Difficulty

Hard 4/5

Required Part

Salus RF receiver relay
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