1 bar Medium

Sime 1 bar Fault Code

Also written as 1BAR — same fault.

The Sime 1 bar fault code means: your boiler pressure is too low, which prevents it from heating the water properly.. It appears on 1 Sime model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: 222 - 228 Ω
Typical repair cost £0 (including labour)

DIY fix possible

Locate the filling loop (usually a silver braided hose under the boiler)Open the valves at both ends of the hose to allow water into the systemMonitor the pressure gauge until it reaches 1.5 bar, then turn off both valves tightly

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Sime models that show the 1 bar fault code

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

Source

Sime 1 bar 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