Hot water loses pressure and runs cold

homewardbound11

Hi ,

been waiting for my plumber for 8 days now . So getting fed up waiting .

pressurised system .

hot water looses pressure at the cylinder and runs cold when a demand is placed on the hot water .

cylinder is warm at top and bottom . ( 2 thermostats for solar panels ) Supply pressure is good from pump at almost 3 bar ( pump and tank in garage) Mains supply is good also and when pump is bypassed in the garage the same thing happens . Ie when hot tap is turned on the pressure on the cylinder drops from just under 3 bar to below 1 bar and then the taps go cold . Turning off the hot tap results in the pressure at the cylinder rising back up and back to normal until the hot tap is turned on again and the same cycle happens again. .

The cold fill of the cylinder is too slow when a demand is put on it ( hot tap). Yet the cold water from taps from-the same pump (outside)does not loose pressure .

thought it was the pressure reducing valve at the pump in the garage but cold water from inside taps doesn’t lose pressure .

could it be one of the balancing valves gone wrong at the fill to the cylinder?

. It must be at the input to the cylinder .

thanks for any replies .