water pressure

hi guys

should the water pressure be much different between the hot tap and the cold tap (normal cold storage feeds cylinder jobbie)

the higher the tank the more pressure.

"the higher the tank the more pressure"

yeah i know that but should they be equal???

dexion said:

hi guys

should the water pressure be much different between the hot tap and the cold tap (normal cold storage feeds cylinder jobbie)

Click to expand...

What tap are you talking about? Kitchen, bathroom basin?
If its the kitchen the water pressure will be higher cos it's mains fed.

sorry should have said its the upstairs bathroom

The bathroom may also be mains fed to the cold taps.
Can you hold your finger over the cold tap to stop the flow of water?
if not it's mains fed.

i have asked the wrong question

thanks for your help anyway because i now realise that the cold supply to the bathroom tap is actually mains fed and so asking about the taps pressure difference was not getting the answer to my real question.

what i was trying to establish is why the pressure available at the shower pump is much greater for the cold supply than it is for the hot supply.

the cold to the pump is fed from the cold tank which also feeds the cylinder so since both the cold supply to the pump and the hot supply to the pump have the same effective head, why is there much greater volume of cold water to the pump than hot water? the taps question was red herring!

there is a valve between the pump and the shower head in each line but if i close the cold and ensure that the pump is only pumping hot the head of water does not seem sufficient to feed the pump properly. is it likley there might be a blockage in the supply to the cylinder or out of the cylinder to the pump or is the case that the extra piping and work the head of water must do through the cylinder causes a pressure drop?

COuld be sucking air down the vent. Try holding a tumbler of water under the end of the vent pipe (over the big tank).
How have you plumbed the hot feed to the pump?
And make sure the hot isn't over 60º - cavitation.

the system has been incoreectly fitted (hot supply to pump teed off the horizontal outlet pipe on top of cylinder) but it did used to work. there has always been a difference in hot and cold supply to the pump even when each was tested individualyand the system worked

the question is should the pressure available from the hot supply to the pump and the cold supply to the pump be equal or should the additional work the head of water has to do to force water thorugh the cylinder cause a difference in the pressure avaliable at the pump between hot and cold