BoilerFaultCodesRavenheat E08 Fault Code
The Ravenheat E08 fault code means: your boiler has detected that there is not enough water in the system to operate safely and has shut down to prevent damage.. It appears on 9 Ravenheat models in our database.
Technical description: Low water pressure
What causes the Ravenheat E08 fault?
This fault occurs when the internal pressure sensor detects that the system water level has dropped below the minimum required for safe operation. The most common reason is a slow leak somewhere in your radiators or pipework, or a failure in the components that regulate pressure, such as the expansion vessel. Without enough water, the boiler cannot circulate heat effectively and shuts down to prevent the main heat exchanger from overheating.
This issue is frequently seen in autumn when homeowners turn their heating back on after the summer, as the change in temperature can highlight small leaks or a loss of pressure in the expansion vessel.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath your boiler.Slowly open the small valves at either end of the hose until you hear water entering the system.Monitor the pressure gauge and close the valves once the needle reaches between 1.0 and 1.5 bar.Reset the boiler to clear the fault code.
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Gas Safe Register →Ravenheat models that show the E08 fault code
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Source
Ravenheat E08 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