E9 High

Sime E9 Fault Code

The Sime E9 fault code means: your boiler has detected that the water pressure inside the system has dropped too low for it to operate safely.. It appears on 1 Sime model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: TBD
Typical repair cost £80-120 (including labour)

DIY fix possible

Locate the external filling loop (a metal braided hose connected to two valves under the boiler)Open both valves slowly until the pressure gauge on the boiler front reads between 1.0 and 1.5 barClose both valves tightly and restart the boiler

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Sime models that show the E9 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Sime E9 fault code information on this page is sourced and cross-checked against the official Sime service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026