Your boiler is temporarily pausing to check if there is enough water pressure before it starts up, which is preventing your heating and hot water from running.

Water pressure sensor check is running, demand (DHW or heating) is blocked

What causes this fault?

This fault occurs when the boiler's internal computer tries to verify there is enough water pressure to run safely but fails to get a clear reading. The most common reason is a failing or blocked water pressure sensor that provides inconsistent data, causing the system to pause as a safety precaution.