Hi,
I have a stuart turner negative head pump serving a bathroom.  When the hot water tap or hot water shower is turned on the pump delivers water intermittently with a approx 5 second runtime before turning off momentarily.

This does not happen to the also pumped cold water using the same pump.

I have bled the pump on the hot side but that was fine and the problem remains.

I have checked that all valves are open between the hot water tank and the pump. The same hot water tanks supplies water to another pump without any problems but is not running when the problem above occurs.

When the hot water runs it runs at a good rate.

Any thoughts on why / what is causng this would be appreciated

thanks in advance

Pat

does the pump have a thermal cut off which your hot water temp exceeds? check the instructions for the pump and reference it against the hot water temp at your taps  , it my be a case of cutting back the hw temp or fitting a blending valve/anti scauld valve before the pump

i'm no expert on shower pumps but i had a similar problem a few weeks ago