23-02-12, 10:36 AM
Quick update.
The engineer visited and (fingers crossed) has fixed it.
The system has what he described as a bypass loop so that when the valves shut the water has somewhere to run round instead of nowhere. There is an adjustable spring tensioned valve that the water pushes open. It was a little too strong for the water to push open cleanly - hence the banging. So he loosened the spring tension and hey presto no more banging so far).
The engineer visited and (fingers crossed) has fixed it.
The system has what he described as a bypass loop so that when the valves shut the water has somewhere to run round instead of nowhere. There is an adjustable spring tensioned valve that the water pushes open. It was a little too strong for the water to push open cleanly - hence the banging. So he loosened the spring tension and hey presto no more banging so far).