Hi
My ensuite shower had very week pressure - cold was just about strong enough to reach the fixed head, hot was non existent. H&C pressure to the bath was adequate, but as I wanted to install a tap-mixer shower here, I decided to have the upstairs pressurised with a pump.
So I=92ve just had a Salamander ESP 75 twin impeller pump fitted to pressurise all hot & cold outlets upstairs. I=92ve also fitted the mixer shower to the bath, which works fine.
However, the ensuite shower, (thermostatic mixer), although it now has good pressure, it=92s output is consistently cold. I=92ve checked its hot supply and it appears to be fine, i.e., isolating its cold supply outputs hot water at good pressure, albeit way too hot for a shower.
The only I can get an acceptable shower is to simultaneously run the cold tap on the bath. The ensuite works fine in this situation, the thermostatic mixer is a joy and responds to the temperature knob as needed. Ecstasy =96 it=92s just a shame I don=92t want to have to run the cold bath tap every time I shower :(
My conclusion is that the cold supply to the mixer is at much greater pressure than the hot. I=92m perplexed why as it is fed from the tank, not from the mains as appears to be a frequent issue from examples I=92ve researched.
I=92ve examined the hot & cold pipe work from the pump to the shower and can=92t see anything particularly different - same pipe diameters, similar length, turns etc.
My questions are thus:-
- should an impeller pump output equal pressure on hot & cold, in which case is my shiny new pump not working properly ? Or does it simply boost input pressures proportionally, i.e., if input hot is lower than input cold, then output hot will also be lower than output cold ?
- Is pressure reducing valve immediately before the cold input to the ensuite mixer r the way to resolve this ?
Cheers Gareth.