D1 alarm, high temperature in furnace cabinet, unit shuts down

Safety: Turn off power and allow the unit to cool before opening panels.

• Check ventilation: Ensure that all ventilation grilles around the Nibe furnace are unobstructed. Remove any stored items blocking airflow.
• Verify installation space: Compare the installation location with Nibe's minimum clearance and room volume requirements. Overheating is common in cramped plant rooms.
• Inspect cabinet fan: If your model has an internal cabinet cooling fan, check that it spins freely and runs when the unit is operating.
• Clean dust: Use a vacuum (power off) to remove dust from electronics and fans.

Reset the D1 alarm after cooling. If it recurs, have a technician test the cabinet sensor and fan.