Dettson furnace cycles on and off very frequently (every few minutes) but maintains temperature.

Safety first: Turn off power before moving thermostat wiring.

• 1. Check thermostat location: Ensure it is not near supply registers, exterior doors, or direct sunlight.
• 2. Adjust cycle rate: In the thermostat installer menu, set the cycle rate appropriate for gas furnaces (often 3–5 cycles per hour).
• 3. Verify tight wiring connections: Loose thermostat wires can cause intermittent calls for heat.
• 4. Consider thermostat upgrade: A modern digital thermostat with proper furnace settings can reduce short cycling.