Thermostat displays E17 and reports incompatible load or wiring

Safety: Turn off power at the breaker before touching any wiring. Confirm power is off.

Steps to troubleshoot E17 (load detection):

• 1. Confirm system type: Verify that your Stelpro smart thermostat is designed for the type of heating system you have (line-voltage electric baseboard, convector, floor heating, etc.). Do not use a line-voltage thermostat on a 24 V furnace or heat pump.
• 2. Check wiring connections: Remove the thermostat and confirm that the line (supply) wires are connected to the correct L terminals and the heater wires to the load terminals, as per the Stelpro wiring diagram.
• 3. Inspect load: Ensure that only resistive heating loads (baseboards, convectors) are connected. Do not connect motors or electronic loads directly unless the thermostat is rated for them.
• 4. Reconfigure load type: In the thermostat setup menu, select the correct load type or wattage range if the model supports this option.
• 5. Test with known-good load: If possible, temporarily connect the thermostat to a known-good Stelpro baseboard heater of appropriate wattage to see if E17 clears. This helps isolate whether the issue is with the thermostat or the original load.
• 6. Replace thermostat: If wiring and load are correct but E17 persists, the load detection circuitry on the thermostat may be defective. Replace the thermostat.

Warning: Never connect a Stelpro line-voltage thermostat directly to a gas furnace or heat pump control board; use a compatible low-voltage thermostat instead.