Thank you.I have contacted just answer on the telephone and explained the situation.I have now registered properly and the cash for my original
question will be refunded.I realise the question is not easy.Why should one shower surge when the one a yard away is OK?It worked ok for a while before it started surging.If the temperature is lowered the surging decreases.If I turn it on to full heat it surges but if I turn the one next to it on the surging stops but the temperature is a lot lower,as is the flow.I suspect that somehow there is a restriction at the hot inlet isolation valve but that involves a deal of work to get to.I want to be pretty sure first!
Thank you.I also think it is due to lack of flow,which leads me back to the inlet isolation valve either partially blocked or not fully open.The pump is heavy duty & is connected to the cylinder via a surrey flange.Flow from good shower 2.01 lts.flow from bad 0.70lts. header tank in loft is raised and aprox 2m.above all 3 shower heads,incidentally directly above the shower that does not flow at all unless pressurised by by turning one of other 2.on momentarily.I doubt that the pump is the problem as it delivers even with more than one on.I will check if the inlet isolation valve is causing restricted flow.There is still the problem of the one will not start?
Thank you.All my isolating valves are inline screwdriver.I shall replace with full flow and feel quietly confident that will cure the problem.Regarding the shower that does not flow until pump activated by using one of the other showers.I suspect there must be some sort of spring loaded entry valve into the mixer that does not open under the pressure produced by the head from the cold tank in the attic.That is odd as it is directly bellow the tank,whereas the others are a few meters.Once flow begins under pump pressure it is perfect.Probably a question for the manufacturers.Unless you have the answer.Thank you for advice so far.