BoilerFaultCodesYour boiler has detected that the water pressure in the system is too low, causing it to stop running for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Low water pressure
What causes this fault?
This fault occurs when the water levels inside your heating system drop below the minimum required for the boiler to operate safely. The most common reasons for this are a leak somewhere in the pipework or radiators, or simply that air was recently bled from the system without topping the pressure back up.
This issue is frequently seen in autumn when homeowners turn their heating back on for the first time and discover the pressure has naturally dropped over the summer months.
DIY fix possible
Locate the filling loop, which is usually a flexible silver hose under the boiler.Slowly open the small tap (or taps) on the filling loop until you hear water moving.Watch the pressure gauge and close the taps exactly when the needle reaches 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 F1 — 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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