E2 Low

Sime E2 Fault Code

The Sime E2 fault code means: your boiler is simply letting you know that it is currently warming up its internal water supply to ensure hot water is ready for you as soon as you turn on the tap.. It appears on 1 Sime model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Preheating function active

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Sime models that show the E2 fault code

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

Source

Sime E2 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