E17
Chaffoteaux
Communication Fault with Room Thermostat / Bus
Furnace shows E17, often associated with external controls or communication.
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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
Incorrect wiring of Chaffoteaux room controller, Broken communication cable, Incompatible thermostat, Faulty control board communication circuit
How to Fix / Troubleshooting
Safety: Turn off power before altering control wiring.
- Check thermostat type: Ensure the connected room thermostat or programmer is compatible with your Chaffoteaux furnace (eBus/OpenTherm vs simple on/off).
- Inspect wiring: Verify that the low-voltage control wires are connected to the correct terminals as per the installation manual. Look for loose or damaged cables.
- Test with link (if allowed): For simple on/off controls, a professional can temporarily fit a link across the room thermostat terminals to see if the furnace runs, indicating a thermostat or wiring fault.
- Reset: After correcting wiring, restore power and reset the furnace. Persistent E17 requires professional diagnosis of the control board and controller.
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Repair Difficulty
Medium
3/5
Required Part
Room Thermostat / Control Interface
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