BoilerFaultCodesTechnical description
Air pressure limiter enables start (contact closed between terminals X8.10 and X8.11) fault: After approx. 51 seconds - Check fan cables and fan plug-in connections, check fan
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the unit fast enough to safely carry heat away from the burner. The most common reasons are a failing internal pump that can no longer push the water or a significant blockage within the main heat exchanger. It can also be triggered by a build-up of sludge in the system pipes that restricts overall flow.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as pump components can seize during periods of inactivity.
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.