BoilerFaultCodesYour boiler has switched itself off because the water pressure is too low for it to run safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler off because pressure too low. Replenish CH system & purge air. Find leak(s) and repair.
What causes this fault?
This fault occurs when the water inside your central heating system drops below the minimum level required for the boiler to operate. The most common reasons are a slow leak from a radiator valve or pipework, or a loss of air pressure inside the expansion vessel which causes water to be expelled through the safety valve.
This issue is frequently seen in autumn when the heating is turned on for the first time after summer, as joints may have contracted or weeped while cold.
DIY fix possible
Locate the two black handles on the filling loop braided hose underneath the boiler.Slowly turn both handles to the open position until you hear water entering the system.Watch the pressure gauge and close both handles once the needle 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 P0.1-0.4 — no call-out fees, no surprises.
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Potterton Powermax HE 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.
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