Display shows E14, furnace may not respond to thermostat commands.

Safety: Turn off power before working on control wiring.

• Check thermostat wiring: At the Termet control board, verify that the room thermostat terminals (e.g., TA/TB) are correctly wired and tight. Inspect the cable for damage.
• Bypass test (low-voltage only): Temporarily bridge the thermostat terminals at the furnace with a short wire. If the furnace starts, the thermostat or its cable is faulty.
• Verify thermostat settings: Ensure the thermostat is set to HEAT mode and the setpoint is above room temperature.
• Check control parameters: In the Termet installer menu (if accessible), verify that the control mode matches the installed thermostat type (on/off vs. OpenTherm, etc.).

If E14 persists with correct wiring and a known-good thermostat, the control board may require replacement by a professional.