Your boiler is currently performing a self-test of its internal pressure sensor and has temporarily paused heating until it finishes.

Water pressure sensor self-test: Water pressure sensor test running, heating demands are blocked.

What causes this fault?

This occurs when the boiler performs a routine safety check to ensure the water pressure sensor is measuring accurately. It is usually a temporary phase during startup or after a refill where the system monitors for pressure stability before firing the burner. If the code persists, it often suggests the sensor is struggling to get a consistent reading or the expansion vessel is failing to regulate pressure changes.