the punter said the boiler was not working as i have no hot water up stairs ,heatline vizo ,i ran kitchen tap no problems,went up stairs ran shower i decreased flow rate and shower was getting hot all of a sudden there was a screech and the shower ran cold, same on basin as i reduced flow rate the water got hot then all of a sudden bang water completely stopped,it's as if some thing on hot water line shuts off when a certain temp is reached or the taps are knackered along with shower valve any thought ,every thing is concealed.