BoilerFaultCodesYour boiler has detected that the water pressure in your heating system is too low to operate safely and effectively.
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 – the heating system needs venting or water needs topping up until the preset pressure is reached. Replace the cable to the pressure sensor replace the pressure sensor
What causes this fault?
This fault occurs when the internal sensor detects that there is not enough water inside the system to safely transfer heat. The most common cause is a slow leak in the pipework or radiators, though it frequently happens after you have recently bled your radiators to remove air. In some cases, the error persists because the pressure sensor itself has failed or the electrical connection to it has become loose.
This code is frequently seen in autumn when homeowners turn their heating back on for the first time or bleed their radiators to prepare for winter.
DIY fix possible
Check the pressure gauge on the front of the boiler; it will likely be in the red zone.Locate the filling link (either a built-in lever or a flexible silver hose) and slowly turn it to add water.Monitor the gauge and stop once it reaches between 1 and 1.5 bar, then ensure the filling link is fully closed.
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A boiler cover plan would cover faults like 2971 B — no call-out fees, no surprises.
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