Furnace shows E17 and shuts down, often during very cold or very hot ambient conditions.

Safety: Disconnect power before accessing the control compartment.

Steps:

• Identify sensor: On some Atlantic furnaces, an ambient or cabinet temperature sensor is integrated on the control board or mounted nearby.
• Inspect for damage: Look for signs of overheating, discoloration, or physical damage to the sensor and surrounding components.
• Check wiring: If the sensor is remote, verify that its wiring is intact and properly connected.
• Replace if faulty: If the sensor is separate, replace it with the correct Atlantic part. If integrated into the PCB, the entire control board may need replacement.

Note: Ensure the furnace is not installed in an environment outside the specified temperature range.