Need Plumbing Advice

xxxpinkladyxxx

I have a problem with my shower. Basically, when I bought my bath, it came with a shower attachment, which is obviously attached to the taps. The problem I have with it is that when I go to use the shower, the water just comes out cold. When I just turn on the hot tap through the shower hose, it comes out hot, but as soon as I turn on the cold tap, it comes out cold. I've tried just turning the cold tap on a tiny bit, but the water is still coming out cold. The strange thing is that when I use the tap (mixer tap) the water comes out fine. What do you think the problem is?

jobbingmusician

I know NOTHING about plumbing, but have been thinking about this one just as a logical problem.

1. Water comes out of tap OK but not out of shower. Water running through shower hose has longer to cool down - but I assume you are running it for long enough.

2. The same water should be coming through the tap and the shower - but it isn't! I wonder if there is something inside the mixer bit for the shower (but not the tap) which is becoming compressed when cold water flows, so that the hot water can't get through. This is a nice logical solution, but is probably not very helpful to you as (if you are like me) you won't want to take the tap to pieces on the vague suggestion of a random MSE'r to see if that's the solution........

(I think it's a pretty good theory, though, as theories go!)

plumb1_2

The problem is almost certain to be unequal pressures,the cold water will be off the mains and the hot tank feed.
You will need to put a pressure reduceing valve on the cold supply to the bath.

shammyjack

Is your system mains pressure fed or does it use a header tank ?

Hot water fed from header tank and cold water off mains pressure could be your problem !

If hot water is header tank fed I would suggest feeding the cold supply to the mixer tap from the same header tank to equalise the pressure !

shammy

moneysavingplumber

plumb1 wrote:

The problem is almost certain to be unequal pressures,the cold water will be off the mains and the hot tank feed.
You will need to put a pressure reduceing valve on the cold supply to the bath.

Obviously I agree with plumb1. It should also have a double-check valve fitted on the cold supply to protect the mains from contamination.