Technical description
Water pressure switch error (lack of water)
What causes this fault?
This fault occurs when the internal sensor detects that the system's water pressure has dropped too low for the boiler to operate safely. The most common reason is a slow leak in the pipework or radiators, though it can also happen if you have recently bled your radiators without topping the water back up.
This issue is frequently seen in autumn when homeowners turn their heating back on for the first time, as dormant leaks or air trapped in the system can cause the pressure to dip.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.