Need advice from a plumber (not a Gynae question).

Discussion in 'Sappers' started by Swamp_Rat, Jan 12, 2007.

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  1. Can anyone tell me how to calculate water pressure please;

    I have water storage tanks running the length of the roof gable (qty 2, 6"dia x 20ft pvc pipe, horizontal, fed by a cystern/ball valve header tank).

    Can you tell me the water pressure that will give if the tap (3ft from the floor) is 17 feet below the bottom of the storage pipes.

    Just wondering if using the 17ft head will give enough pressure to a.) fill the washing machine that needs 5psi to open the pressure switch and b.) get enough pressure to have a shower.

    Will the bore of the pipe from the storage tanks affect the water pressure?

    Any tips or advice would be greatly appreciated, thanks in advance.

    Edited to add; this isn't a competition and there are no Blue Peter badges or Crackerjack pencils involved.
  2. Sorry mate cant help you on that one ,but I do have a photo of the Queen Mum reversing a fire engine down a hill ,if you want a copy :wink: :wink: :wink: :lol:
  4. Firstly, the diameter of the discharge pipe is not relevent.

    Secondly, and most importantly:

    A head of 10 m will produce a pressure at the discharge point of 1 Bar.

    This is known as static head.

    17 feet is 5.18 m, so you are looking at around 0.5 Bar. 0.5 Bar is approximately 7 psi.


  5. heh

    I don't have that one.

    I've got two of her son in law greasing the cat's boils if you want a swap. No gloves, the brave bastrad.
  6. Good stuff. I've been trying to figure this out for ages.

    Thanks for your help, much appreciated.
  7. Presuming you have enough capacity in the storage tank, you could fit a cheap pump and a flow switch to increase the pressure.

  8. I did consider that too mate.

    All the house lights are 12 volt marine fluorescents so a bilge pump running from a pressure switch and relay would do the job I reckon.
  9. I'd be surprised if a bilge pump would provide enough pressure boost. Best bet is a shower pump.

  10. They must have showers on boats so yep yep, that's what I'll have a look around for. Set the pressure sensitive switch to cut in when the water pressure drops, to trigger the relay and fire up the pump.

    With all the info you guys have put out I can have a better idea of what I need to do.

    Many thanks, you have made an old man very happy.