BoilerFaultCodesYour boiler has detected that the water pressure is too low for it to operate safely, likely due to a small leak or air in the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Temporary error caused by system water pressure, water leak on boiler, water leak on system.
What causes this fault?
This fault occurs when the internal sensor detects that there isn't enough water pressure to safely circulate heat around your home. The most common reason is a slow leak from a radiator valve or a pipe joint, but it can also happen if you have recently bled your radiators and didn't top the pressure back up.
This issue is more common in autumn when homeowners turn their heating back on for the first time, as the change in temperature can highlight small leaks that developed over the summer.
DIY fix possible
Locate the filling loop (braided silver hose) underneath your boiler.Slowly open the valve(s) until you hear water entering the system.Watch the pressure gauge and close the valves once it reaches between 1.0 and 1.5 bar.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like H.02 – .06 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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