Freshwater pump: how much oomph?

[Geoff S.]

I have a 50-something foot boat, with galley sink, two wet (shower) heads, and a bar sink. What kind of gpm and/or psi do I want from a 12v freshwater pump to service all that? I'm looking at a Flojet 2840 (4.5gpm) that Valley Marine has at 40% off closeout, but with the additional hassle of getting it to Trinidad, I'd want to pick the right pump regardless of purchase price. I'm also going to put in a washdown pump in the fore; would this pump (perhaps a second unit to the house pump) be up to that task?

Anybody had any experience with Flojet? Reliable? Durable?

[knottybuoyz]

Hey Geoff

We're headed to Valley Marine on Saturday to look for bargains. Would you like me to get you some specs on the flojets? They might have other makes/models available that aren't on their web site.

Our 1987 vintage boat has a flojet that appears to be original and still works fine. I think most 12v pumps that I've looked at give about 4-5 gpm. Dunno what pressure though. Do you have an accumulator in your system?

Let me know if I can help in anyway.

Rick

[Geoff S.]

Rick, you rock! Sure, check things out for me, thanks! At this point I'm starting completely over with the entire plumbing system, so the Valley Marine system with accumulator and the works sounds like a good idea; I just haven't a clue if 4.5 gpm will have enough balls for the whole boat.

I have quite the shopping list (electrical goodies, deck hardware, galley stove, etc. etc. etc.) if you want it! (grin).

[knottybuoyz]

Geoff

Send me the whole list. I'll talk to them and see if they'll bundle it all up and ship it down. If the liquidators haven't been in yet there still might be some bargains. On a bulk purchase they may even knock off a few more % points. Who knows, doesn't hurt to ask eh?

Rick

[GordMay]

A single fixture water system usually requires about a minimum 2.5 GPM (open flow) Pump. Multi-fixture systems generally* require larger pumps.

Some Marine Fresh-Water Pumps:
Groco “Paragon Senior” #PSR12V @ 11 GPM - 30-50 psi (multi-fixture use)
Groco “Junior” # PJR-A12V @ 7 GPM - 20-40 psi (single fixture use)
Flojet #R4525-743 @ 4.5 GPM open flow rate
Jabsco (Par) #31620-0092 @ 4.3 GPM open
Shurflo “Aqua King” #3901-0216 @ 3.0 GPM - 55 psi

* An oversized pump in a system may result in erratic pump cycling, pulsating water flow, temperature fluctuations, and excessive power consumption as the pump starts and stops.

[Alan Wheeler]

Geoff, one of the biggest helps in a water system is good size piping. The longer the distance the bigger the size.
It's all very well to have good pressure and good flow on a boat, we do and love it, but also remember that it means more water tends to get used.

[senormechanico]

How about a couple of pumps in parallel?

[Geoff S.]

So, how does one begin to spec a water system? My water tanks (one 100gal, one 50gal) are roughly midships; Galley sink will end up being within 15 feet of the tanks; bar sink will be 10-12 from the tanks; forward shower and sink will probably be the longest run, maybe 20 feet; aft shower and head 15-20. How many taps running simultaneously does one size the pump for? Maximum usage might be somebody washing up in the galley with two people simultaneously taking showers, but I can't think that's going to happen often. I really don't have room for more than the current 150 gal tankage, so barring the acquisition of a watermaker (a toy I want someday when I'll be able to spend more time per year aboard), I'm probably going to have some quasi-military water use policies in effect.

Thoughts on how to proceed?

And Rick, you're my newest bestest friend! I'll PM or email you a list; tell me which you'd prefer.

[windthief]

My flojet 3.8g just took a crap after a year or so. I was very disappointed and am working to get a warranty claim. The unit was very close to to the aft tank and the "y" valve also a very dry spot. I have now gone to shurflow we'll see how that goes with there 4.4g unit.

[Pblais]

I just installed a 3.5 Shureflo where the galley and head are next to each other. It seems fine but for us but more than two users at the same time I think 4 would be way too little. I needed it quickly so just bought it at a good price. I would prefer a 4.0 but 3.5 makes you think about the water you are using.

Rather than parallel pumps I would think about multiple pumps with dedicated lines. Accumulator tanks are great for small users.

[knottybuoyz]

Lori and I kicked around the store on Saturday for about an hour. We picked up a few trinkets and a few elec. parts for the build that seemed to be good deals. The shelves were pretty much picked over but there was a lot of small sailboat hardware & rigging still available.

http://www.valleymarine.ca/

We dropped off Geoff S's wish list but the staff wasn't overly enthusiastic about helping to clear out the inventory so I don't imagine they even called Geoff back.

Sale ends tomorrow so it might be worth checking out for last minute deals.

Rick

[Geoff S.]

Actually, Rick, Valley did indeed call and leave a vm, apologizing that they didn't have anything on my list, and as they were only going to be in business for another two days were not ordering anything. They said if they could be of any service to give them a call (not sure how they could serve given the foregoing disclaimer). It was actually quicker and more professional response than I've gotten from many vendors still in business! Sounds like they were good folks, and it's too bad they couldn't hang in there.

[Niorn]

You should look at the new VSD pumps from Flojet and Jabsco. They need no accumulator tank and basically give you water on demand as though do not depend on a pressure switch. The reviews have been good so far.

[Geoff S.]

Thanks, Niorn, I'll check 'em out.