Dettson furnace shows E10; unit may start but shuts down quickly or will not respond to thermostat.

Safety first: Turn off power before accessing control wiring.

• 1. Check communication cables: If your Dettson furnace uses a communicating thermostat or zoning, locate the communication harness between the main control board and the interface module. Ensure all plugs are fully seated.
• 2. Inspect low-voltage wiring: Look for pinched, cut, or shorted communication wires (often labeled A/B, Data+, Data-). Repair or replace damaged sections.
• 3. Remove recently added accessories: If E10 appeared after installing a new thermostat or zoning panel, temporarily revert to the original configuration to see if the error clears.
• 4. Power reset: Turn off power for 5 minutes, then restore. This can clear transient communication faults.
• 5. Replace faulty module: If wiring is intact and E10 persists, either the main control board or the interface/thermostat module may be defective. Replacement and reconfiguration should be done by a technician familiar with Dettson communicating systems.