BoilerFaultCodesSime 0 bar Fault Code
Also written as 0BAR — same fault.
The Sime 0 bar fault code means: your boiler has lost the water pressure required to function, which is preventing it from heating your home or water.. It appears on 1 Sime model in our database.
Technical description: 297 - 320 Ω
DIY fix possible
Locate the external filling loop, which is usually a silver braided hose connecting two pipes under the boiler.Open the valves on both ends of the filling loop slowly to let water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically between 1 and 1.5 bar).Close both valves tightly and ensure the filling loop is disconnected if it is a temporary hose.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like 0 bar: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Sime models that show the 0 bar fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Sime 0 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