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Fresh Water system Pressure 43 Post

Discussion in 'Post Yacht' started by Greg Page, Aug 12, 2022.

  1. Greg Page

    Greg Page Active Member

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    Want to check what pressure others fresh water system is. Ours currently has a 40 psi pump, but everyone is out of stock on the 40 psi. Wondering if I could use a 60 psi which is available.

    Thanks - Greg
  2. Greg Page

    Greg Page Active Member

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    Did an experiment. Hooked the boat to our dock water on the dock water inlet. Put a pressure gauge on the cockpit wash-down outlet connected to the fresh water system. My gauge apparently is dying from old age so results are interesting but not accurate levels. When the internal fresh water system pump shuts off the gauge at the pump reads 40 psi. My gauge on the cockpit outlet only read 10 psi. When I put the stand alone gauge on my dock water directly it reads 60 psi. From prior tests (when I had a water powered boat lift) our dock water usually reads 90-100 psi. When I turned our dock water on to the boat the gauge on the cockpit washdown also read 60 psi, which I believe to be 90+ psi in realilty. It appears either our boat does not have a dock water inlet pressure regulator (although I thought all Posts did) or the regulator is failed or set very high.

    That said, the system does not leak anywhere I could tell in the couple minutes at 90+ psi. It has been on Baltimore city water for several days with no apparent trouble, which normally should be about 75 psi.

    Still uncertain about installing a 60 psi pump, but seems to indicate system can handle that and more.

    Ordered a new gauge to repeat the test with hopefully accurate values next week.
  3. MBevins

    MBevins Senior Member

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    Most pumps have the ability to adjust the pressure, odds are you can dial the 60lbs back to about 50.
  4. Capt Ralph

    Capt Ralph Senior Member

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    Please remember, small copper, plastic, rubber lines with lots of restricting fittings will only flow so much to your shower head.
    The comfort is a contestant stream.
    PSI is one thing, a well sized accumulator is the magic. :D:D
  5. Greg Page

    Greg Page Active Member

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    The manufacturer carefully notes that adjusting the pressure (when they tell you where the adjuster is) violates the warrenty, although it appears the only difference in the models is the setting of the pressure switch. Others have done that going both down and up. The other side effect of the higher pressure is the 60 psi pump is listed in different places as needing, depending on the source, either a 20 or 25A breaker.

    I may have found a 40 psi pump but won't know if really in stock till I can call and confirm next week, the ones listed in stock that I have called so far do not have any even though their online order systems say they do.

    The current accumulator does well at holding pressure and letting the pump switch out and back in during steady water use. We only have the galley, one head sink and shower, and now the fresh water flush head so not a terribly high volume use. The new pumps are all rated at 4 GPM free flow vs the 3.5 GPM rating of the current pump so should give a little more head room.
  6. ranger58sb

    ranger58sb Senior member

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    What is the plumbing? PEX? Or...?

    -Chris
  7. Greg Page

    Greg Page Active Member

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    Copper with short lengths to the pump of reinforced clear water hose (listed rating 250 psi). Not as concerned about what I know as much as if there is something I didn't account for. I need to check what pressure the accumulator is set at, half the label is gone so no way to tell what it is rated for but it is steel.

    Open item is what size breaker is on that line. Most of the 12V on the boat has 20A breakers, but to check label on individual breaker I have to remove the feed buss bar.
  8. DOCKMASTER

    DOCKMASTER Senior Member

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    When you say a 40 psi pump are you talking about cut out (off) at 40 psi? When does the pump cut in? If 40 psi is max and your cut out pressure that seems low to me. My pump cuts in at 40 psi and out at 60 psi
  9. Greg Page

    Greg Page Active Member

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    Our current comes on at 20 off at 40. The 60 psi pump would come on at 40 off at 60.
  10. MBevins

    MBevins Senior Member

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    For what it's worth, mine is on at 40, off at 60 as well.
  11. Greg Page

    Greg Page Active Member

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    Thanks. That is what I'm leaning to put in.
  12. DOCKMASTER

    DOCKMASTER Senior Member

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    I’ve seen on at 30, off at 50 but have never seen 20-40. At 20 psi it must barely dribble out of the faucet
  13. Greg Page

    Greg Page Active Member

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    Was fine with non flow restrictor aerator.
  14. Greg Page

    Greg Page Active Member

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  15. MBevins

    MBevins Senior Member

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    You'll find a world of difference by Just increasing the accumulator pressure.
  16. Greg Page

    Greg Page Active Member

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    Did pump change before accumulator. Noticed big improvement with pump (the old one probably has been dying for a while), didn't notice much with accumulator precharge.
  17. MBevins

    MBevins Senior Member

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    The precharge makes a huge difference in time between pump repressure of system.
  18. Greg Page

    Greg Page Active Member

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    Agree. I only looked at flow. Didn't look at cycling time.
  19. Stainless45

    Stainless45 Member

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    Are you getting any fluctuations in tap/shower temperature when the pump kicks on and off? Looking at the Jabsco instructions you linked, I may need to add an expansion tank like the diagram suggests. Pump is new, 5 gpm, not sure on the pressure will have to check
  20. Greg Page

    Greg Page Active Member

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    Can't comment on temp as the water heater hasn't been on. Water from the tanks is probably 85-90. Will have the heater on this week as going on a 6 day trip.

    No noticible change in flow before the pump kicks in. With the old lower pressure/probably dying pump and the PO not charging the accumulator there was a noticible drop. There was enough label to read the p/n (1ET2G12F) so could verify the accumulator is 2 gallons. It's now pre-charged to 35 psi, 5 psi below the pump switch-on pressure.

    Here is how it is plumbed (picutre is old pump).

    IMG_4282.jpeg