BoilerFaultCodesRavenheat 25E Fault Code
The Ravenheat 25E fault code means: your boiler has detected that the water inside the main heating unit has frozen, which is preventing the system from operating to avoid damage.. It appears on 7 Ravenheat models in our database.
Technical description: Main heat exchanger frozen
What causes the Ravenheat 25E fault?
This fault occurs when the temperature sensor inside the boiler detects that the water within the heat exchanger has reached freezing point. The most common cause is the boiler being located in an unheated area like a garage or loft during a cold snap without adequate frost protection. It can also be triggered if the external condensate drainage pipe reflects a blockage caused by ice, preventing the system from circulating safely.
This fault is almost exclusively seen during the winter months when external temperatures drop below freezing for extended periods.
DIY fix possible
Check if the condensate pipe (the plastic pipe leading outside) is frozen and thaw it with warm water or a heat pack.Increase the room thermostat temperature and wait for the ambient heat inside the house to naturally thaw the unit.Reset the boiler once the system has thawed completely.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ravenheat models that show the 25E fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ravenheat 25E fault code information on this page is sourced and cross-checked against the official Ravenheat service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026