Your boiler has reached the maximum allowed temperature for heating your hot water cylinder and is pausing operation as a standard safety limit.

Maximum set value for target cylinder

What causes this fault?

This occurs when your boiler reaches its temperature limit while heating your hot water cylinder, causing it to pause temporarily to prevent overheating. It often happens because the boiler is producing heat faster than the cylinder can absorb it, which is typical once the water in the tank is nearly at its target temperature. The boiler is simply regulating itself rather than failing.