hi,just fitted a thermostatic bar, switched it on and it runs for 1/2minute,loses pressure and stops,when i turn it over the safety switch to high water comes back on but is too hot,my hot water is supplied by combi-boiler(brandnew),cold water from tank in loft,with supply to the bar taken from hot/cold pipes in bathroom.pressure from shower is good.one suggestion was to fit a water pressure equalising valve but is this the only solution?.