BoilerFaultCodesYour boiler has detected that the water pressure in the system has dropped below the minimum level required to operate safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: System pressure too low
What causes this fault?
This fault occurs when the water pressure inside your heating system drops below 0.5 bar, which is too low for the boiler to safely heat your home. The most common reasons are a leak somewhere in your pipework or radiators, or because the system was recently bled and hasn't been topped back up with water.
This issue is more common in autumn when homeowners turn their heating back on for the first time and discover pressure has naturally seeped out over the summer months.
DIY fix possible
Locate the integrated filling link handle underneath the boiler (on some models) or the external braided filling loop.Slowly pull the lever or open the valves to allow water into the system while watching the digital display or pressure gauge.Close the valves firmly once the pressure reaches 1.5 bar and the fault code disappears.
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 2971 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
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.
Affiliate links — we may earn a commission at no extra cost to you.