Rushing sound on H/W only

Hi, my Glowworm Compact gas combi keeps making this rushing sound after using the hot water. It will keep this up indefinitely until you turn the hot and or cold taps on and off quickly a couple of times. This fault will also stop the central heating coming on if it is still rushing when the heating timer approaches an ON period, but has no effect on the heating if the heating is already on when you use the hot water. Any ideas please? Cheers.
Jon

Sounds like air stuck in your pump because someone thought the little tyre valve cap thingy on the air relief valve should be closed.
Open it ½ - 1 turn.
Cant say any more than that right now because you didnt read this //www.diynot.com/forums/viewtopic.php?t=6026