fresh water dual pump setup

[bigbill]

i know i asked this question a few years ago,my water system is only 110vac with a shallow well pump, i want to add(make original, the wiring is there) a 1
2vdc pump also. can anyone draw a diagram, or post a picture of their setup? a fe questions.... do i need check valves? , and why? thanks, bigbill p.s. AT 3.50 A GALLON, I DONT WANT TO HAVE TO RUN THE GENSET FOR FRESH WATER.

[Will]

You could install a DC pump for backup. You could have both check and isolation valves configured on both pumps to allow you to completely remove one of the pumps for repairs without loosing fresh water service. Our 43' is setup like that.
Will

[davidwigler]

You could also install an inverter to run the AC pump, and other items. I have the same issue - no DC pump.

[bigbill]

will, i would like the setup to run the 110v pump when the gen is running(at a higher cutoff pressure than the dc pump), and when the gen is not running the 12v pump would take over. hopefully no need for manuel valves. this way, the 110 would do most of the duty. the only time the 12v pump would run, is when there is no ac for the 110 pump, or when the pressure drop, and the 12v pump kicks in to build the pressure back up.
david, i dont have an inverter, and dont plan to add one.. there are a few time that i could shut down the genset, but would still like to have water pressure. thanks for everybodies input and ideas. bigbill P.S. any advice on the best 12 volt pump.......good, bad, or ugly

[Will]

No problem setting the cut in pressure on the 12V pump below that of the AC pump allowing the AC pump to be your primary service pump. Isolation valves would only be necessary if you wanted remove one pump for repairs while maintaining system pressure.
Will

[MikeP]

Frankly, I can't see any point in an AC water pump on a boat at all. A second (back up) DC pump would be nice to have but JUST an AC pump on a boat makes no sense to me. A DC pump will work under all circumstances; an ac can only work when on shore or genny power (or on the inverter - but that just requires even more battery power). Why have a pump that requires you to be running a generator full time when you are away from the slip?

[captainwjm]

I have that set up, and as Will described it is easy to do without any check valves.

[Jaxfishgyd]

Ditto to what MikeP said.. there's a LOT of 12v water pumps out there. I put a variable speed in ours about 4 yrs ago and have zero problems with it and we are full time liveaboards

[bigbill]

charlie, what brand and model did you use? i like the idea of 2, 12volt pumps, but i already have the 110v pump. maybe next time it gives me trouble i may toss it.

[GJH]

I have the dual AC shallow well / Galley Maid 32v set up. The shallow well pumps are really wonderful, pressure wise and maintaining flow. And not very expensive. So we use the shallow well as the default at the dock and when the genny is running, and the Galley Maid other wise.

I like having the redundancy and back up on two separate power supplies. It has come in very handy. Hooking the AC pump to the inverter system was more trouble than it was worth, also since I already had the 32v system in place (but not working when I bought the boat) You never know. The pumps are plumbed with Sea Fit compression fittings on their outlet sides. so it is easy to take out of service by capping it off.

You will see a couple of gate valves in this picture courtesy of the PO which are unnecessary. I added a check valve downstream of the Galley Maid, the Craftsman has one built into its intake. While there is another check valve down by the tank, the GM seems to run better having one closer to it. Note that both pumps share the same pressure tank. I had to move the pressure switch for the GM up closer to the tank, other wise the diaphram-type action of the GM interacting with the switch right on it caused a "chattering" which damaged both pump and switch. The GMs usually are mounted on their own little pressure tank. All in all, it is really not that complicated a set up and it works great.