Grant Insulation or Casing Seal Failure

Boiler casing feels excessively hot to 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

Missing or damaged internal insulation panels, Gaps in combustion chamber door seal, High boiler flow temperature setting, Blocked heat exchanger causing hot spots

How to Fix / Troubleshooting

Safety: Avoid prolonged contact with hot surfaces. Turn down the boiler thermostat slightly until inspected.

User actions:

Reduce the flow temperature setting if it is at maximum.

Engineer actions:

Inspect internal insulation panels and replace any that are damaged or missing.
Check and renew the combustion chamber door seal if hardened or cracked.
Verify correct combustion and circulation to avoid local overheating.

Repair Difficulty

Medium 3/5

Required Part

Combustion chamber door seal

Check Price on Amazon

We may earn a commission from links on this page.