BoilerFaultCodesPotterton E117 Fault Code
The Potterton E117 fault code means: your boiler has shut down because there is too much water pressure in the system, which could lead to leaks if not addressed.. It appears on 1 Potterton model in our database.
Technical description: System pressure too high (>2.9 bar)
What causes the Potterton E117 fault?
This fault occurs when the water pressure inside your heating system rises above a safe operating level, triggering a safety shutdown. The most common reasons are that the filling loop was left slightly open after topping up the system, or an internal component like the expansion vessel has failed and can no longer manage the pressure changes as the water heats up.
DIY fix possible
Check that the filling loop valves are tightly closedTurn off the boiler and allow the system to coolBleed water from a radiator using a bleed key to reduce pressureMonitor the pressure gauge until it returns to between 1.0 and 1.5 bar
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Gas Safe Register →Potterton models that show the E117 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton E117 fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026