E15 error; controller indicates door or hatch open

Safety: Do not bypass door safety switches; they prevent operation with open panels.

• Identify the door or service hatch switch (microswitch) on the ash door, burner door, or main service panel.
• Check that the door closes fully and presses the switch actuator lever or plunger.
• Adjust the door latch or hinges if the door is sagging and not engaging the switch.
• Inspect the switch for physical damage and test continuity with a multimeter when pressed.
• Repair or replace damaged wiring to the switch.

If the switch tests faulty, replace it with a similar temperature‑rated microswitch approved for Defro furnaces.