Thermostat powers on but does not call for heat even when setpoint is higher than room temperature

Safety: For menu and app checks, no power-off is needed. Turn off the breaker only if you will remove the thermostat or access wiring.

Steps to troubleshoot no heat call:

• 1. Verify mode: Ensure the thermostat is in HEAT mode and not in OFF, AWAY, or FROST PROTECTION mode. Check both the display and the Stelpro app.
• 2. Override schedule: Temporarily disable schedules or set the thermostat to manual mode. Increase the setpoint at least 3–5°C above the displayed room temperature.
• 3. Listen for relay click: When raising the setpoint, listen closely for a click from the thermostat. No click may indicate the relay/triac is not energizing.
• 4. Check output voltage (advanced): With power ON and a heat call active, measure voltage at the load terminals. You should see full line voltage when the thermostat is calling for heat. If not, the output stage may be defective.
• 5. Confirm temperature reading: If the thermostat thinks the room is warmer than it is (sensor error), it may not call for heat. Compare with a separate thermometer.
• 6. Factory reset and reconfigure: If settings appear correct, perform a factory reset and reconfigure the thermostat. Test again.
• 7. Replace thermostat: If there is still no heat call and no output voltage despite correct wiring and settings, replace the thermostat.

Note: Always verify that the connected Stelpro heater itself is functional by testing it on a known-good control.