Defro Overheating of Casing / Insulation Degradation

Furnace casing or control panel becomes excessively hot to the touch during operation

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Internal insulation damaged or missing, Blocked convection air paths, High boiler temperature with poor circulation, Fan failure in casing (if equipped)

How to Fix / Troubleshooting

Safety: If surfaces are too hot to touch, reduce boiler output or switch off burner and allow to cool.

Check that ventilation openings around the furnace are not blocked.
Verify that system circulation is adequate and radiators are absorbing heat.
Inspect internal insulation panels (technician level) for damage or displacement.

Excessive casing temperature can damage electronics; have a technician inspect internal insulation and heat paths.

Repair Difficulty

Hard 4/5

Required Part

Boiler Insulation Panels

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