Thermostat cannot detect or use external floor sensor (no error code shown)

Safety: Turn off power at the breaker before accessing thermostat wiring.

Steps to get floor sensor working:

• 1. Enable sensor mode: In the thermostat configuration menu, select the control mode that uses the floor sensor (floor or floor+air) as per Stelpro instructions.
• 2. Verify wiring: Ensure the two floor sensor wires are connected to the correct sensor terminals and not to line or load terminals.
• 3. Tighten terminals: With power OFF, tighten the sensor terminal screws and ensure no copper is exposed.
• 4. Check sensor type: Confirm that the installed floor sensor is a Stelpro-compatible NTC with the correct resistance curve. Using a different brand sensor may cause misdetection.
• 5. Measure resistance: Disconnect the sensor and measure its resistance at room temperature. Compare with Stelpro specifications.
• 6. Replace sensor: If the sensor reading is far from expected, replace it with a Stelpro floor sensor.

Note: Some thermostats will silently fall back to air control if the floor sensor is not detected; always verify configuration after wiring.