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Discuss Determining cold feed and shower pump criteria in the Bathrooms, Showers and Wetrooms area at UKPlumbersForums.co.uk.

  1. Marc Taylor

    Marc Taylor New Member

    Before I start I believe I need to determine whether my bathroom cold feed is mains or from the loft tank.

    Would turning on the basin and bath taps and closing my stop cock be the test?
     
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Open the bath/basin tap do you hear the tank running

    Or you can do what you have suggested Open the kitchen cold tap first tho so you can confirm it's off
     
  3. Marc Taylor

    Marc Taylor New Member

    Shaun thank you for your reply. What I did was open both taps having turned of the ground floor stopcock and nothing came out of either tap and the toilet did not refill
     
  4. Marc Taylor

    Marc Taylor New Member

    so have I identified bathroom cold is mains fed?
     
  5. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    correct so the tank only prob supplies the hot cylinder
     
  6. Marc Taylor

    Marc Taylor New Member

    No as I know the hot tank is gravity fed, did I need to do that as well
     
  7. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    No dopy me read that as I've opened bath taps and no water came out :D

    Yes you have found the cold main
     
  8. Marc Taylor

    Marc Taylor New Member

    Apologies Shaun logged out and forgot my new password hence my delay.
     
  9. Marc Taylor

    Marc Taylor New Member

    My primary question is the bathroom is my bathroom is 4 mtr by 3 mtr, in opposing corners is the bath and the hot water cylinder. The bath having a bristan mixer tap unit one spout and a knob you pull up to fed a shower. in the opposite corner at 1.5 mtr the hot water cylinder fed from a cold tank in the attic. this set up will not hold the shower knob up.
     
  10. Marc Taylor

    Marc Taylor New Member

    so I invested in a Salamander Pump, with Salamander declaring this set 'Negative feed' with cold mains being blended with pumped hot. my plumber feels this is incorrect, another call to Salamander who maintain this criteria over the relative heights of cylinder cold tank and shower head, can you advise. Salamander have sown seeds of doubt, I do not challenge my plumber but the pump once turned on is none returnable, I'm popping out to run my son home back shortly Shaun.
     
  11. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Correct and probably the cold is pushing the hot back unless you have check valves etc
     
  12. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Do you have a single or dual pump eg connections one side or both

    As your feeding a bath mixer / shower

    Really you should have a twin negative pump

    So both feeds are balanced and equal pressures

    This will mean taking a feed from the tank and your hot water cylinder

    Hope this answers your question
     
  13. Marc Taylor

    Marc Taylor New Member

    The pump Salamander recommended is the "
    The CT Force 30 SU Universal pump from Salamander Pumps has a robust brass end and a brass impeller. This pump is therefore designed to meet the increased demands for water supply within the home.
    This single ended pump will quietly and efficiently boost the hot or cold water supplies to the shower or individual taps and outlets in a negative head gravity fed installation. " Your comments gratefully recieved.
     
  14. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Right ok so it's a single pump

    So your asking if mains cold and pumped hot is ok ?
     
  15. Marc Taylor

    Marc Taylor New Member

    Yes and is my set negative feed. I noted within their spec sheet "
    The CT Force 30 SU Universal pump is a 3.0 bar single regenerative shower pump suitable for boosting water performance in a gravity fed negative or positive head system. It can be used when the cold water is mains fed." which confuses me further
     
  16. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Simple way for neg or positive head

    Neg needs the pressure to drop eg from 3 bar to 2.5 before it will pump

    Positive head needs x amount of lpm flowing through it before it will pump

    Normally for a single outlet 2 bar is enough

    The thing you have to watch is your incoming mains pressure at the outlet

    If this is below the pumping pressure of the pump

    Eg mains pressure at the tap is 2 bar
    And pump hot is 3 bar

    You will get the hot pushing the cold back through the tap (this is why these days most high pressure taps include check valves)
     
  17. Marc Taylor

    Marc Taylor New Member

    Right when I took the pressure albeit from kitchen mixer tap 2 running mtr from the stop cock it was 5 bar or 80 psi, does that have a bearing?
     
  18. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Ooo that's some main

    Do you have a pressure reducing valve fitted ?
     
  19. Marc Taylor

    Marc Taylor New Member

    No but reading between the lines I thought I may hear this, whats the likely outcome if the negative pump and such pressure are paired
     
  20. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    I would say cold fighting the pump at that cold pressure

    Do you know dynamic pressure eg with an outlet open when testing ?
     
  21. Marc Taylor

    Marc Taylor New Member

    No all I did was screw the pressure gauge onto the tap and open it
     
  22. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Could you do a dynamic test tomorrow?
     
  23. Marc Taylor

    Marc Taylor New Member

    you know the irony we can shower happily with what weve got with the shower head lower than usual, balancing the temp ok,that final 500mm lift and not enough hot and to hold up the button I've just cut a section of plastic pipe and bob's your uncle a shower
     
  24. Marc Taylor

    Marc Taylor New Member

    I'll happily attempt a dynamic test tomorrow
     
  25. Marc Taylor

    Marc Taylor New Member

    Shaun thanks for your help and time, I'll conduct a dynamic test tomorrow, if I'm going to obtain the pressure reducing valve and swap my pump I've got until Thursday to place my order hence my urgency. Talk tomorrow.
     
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