I fitted a Torbeck valve to my cold water storage tank exactly a year ago. I also fitted one of the flow restrictors provided in the kit. Everything has been fine until about a month ago. Now I get about one minutes worth of 'thumping' noise as the valve tries to shut off. It does eventually stop. This only seems to happen after either of the two toilet cisterns are flushed. It doesn't happen when a bathful of water is drawn off.
Could the small amount used by the toilets be setting up a small wave causing the Torbeck to shut - open - shut - open etc??
Regards Chris.