Dettson
Relay Operation Without Heat Call Completion
Dettson furnace occasionally emits a clicking sound but does not start a heating cycle.
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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
Loose low-voltage connections, Intermittent thermostat, Failing control board relay, Voltage drop on 24V circuit
How to Fix / Troubleshooting
Safety first: Turn off power before tightening connections.
- 1. Inspect low-voltage wiring: Check all thermostat and safety circuit connections at the control board for tightness.
- 2. Test thermostat: Temporarily jumper R to W at the furnace control board. If the furnace starts reliably, the thermostat or its wiring may be at fault.
- 3. Monitor control board: If relays click but the corresponding component (blower, inducer) does not start, the board or component may be failing.
- 4. Replace faulty part: Replace the thermostat or control board as indicated by testing.
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Repair Difficulty
Medium
3/5
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