BoilerFaultCodesYour boiler has too much water inside it, which has caused the pressure to rise to a level where the system may shut down or leak to protect itself.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Upper water pressure (>2.7b)
What causes this fault?
This fault occurs when the water pressure inside your heating system exceeds safe operating limits, often because the filling loop was left open or has started to leak water back into the system. It can also happen if the internal expansion vessel, which manages pressure changes as water heats up, has lost its air charge or failed. Effectively, there is too much water or not enough room for it to expand, forcing the boiler to shut down for safety.
This fault is frequently seen in autumn when homeowners top up their boiler pressure after a summer of inactivity and accidentally overfill the system.
DIY fix possible
Check that the internal or external filling loop valves are tightly closed.Locate a radiator and use a bleed key to release water into a container until the pressure gauge drops to 1.5 bar.Ensure the black plastic filling knobs underneath the boiler are turned fully off.
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 2.7bar — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm 30ci 30si 35ci is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.