E25
FAULT CODE
Ravenheat
Heat Exchanger Frozen
High Severity
DIY Check Possible
The main heat exchanger has frozen. This typically occurs when the boiler is in an unheated space during very cold weather.
Cold Weather Note
E25 occurs when the boiler is in a cold location such as an unheated outhouse or loft. Frost protection must be enabled.
Step-by-Step Fix Guide
-
Step 1
Turn off the boiler
-
Step 2
Allow the boiler to warm up naturally if the ambient temperature rises
-
Step 3
Do not use open flame to defrost
-
Step 4
Once thawed, reset the boiler
-
Step 5
Ensure the boiler is in a frost-protected space or the frost protection setting is enabled
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.