Fresh water plumbing question

Ritchard · #1 (**permalink**) 12-16-2011

hi y'all,

One of the issues I would like to address on my new-to-me '79 Endeavour 32 over the winter is a better pressurized water system.

I have in place an old belt-driven, piston style pump, not exactly, but kind of like this:

The pump is currently installed without any kind of expansion or accumulator tank, so while it delivers good pressure, it can only store up as much pressure as the flex of the plastic lines allows. It also seems to have no pressure sensor of any kind. This means you have to keep periodically running the pump to pressurize the system. If you don't turn the pump off in time, it will thermal protect itself, and will not come back on for a while.

Not the worst situation ever, but I could do better. As I am in my first shockingly expensive year of old boat ownership, I'd like to keep the cost modest.

I am wondering if I should install an accumulator tank into my existing system, as that would allow me to store a lot more pressure and use the pump less frequently. Or should I replace the current pump with a sensor switching pump, or replace the pump AND add a tank.

I can low-buck a 2 gallon hot water expansion tank from Home Depot for $50. A pump will run me maybe $120. However I have seen these pressure sensing ones with the explicit direction to NOT hook it into a system with an accumulator tank, so I think they would cycle a lot - but at least they shut themselves off.

I am a little confused now. Any input?

Thanks in advance,

Ritchard

kd3pc · #2 (**permalink**) 12-17-2011

water systems on boats have come a long way since 1979....nothing wrong with that style pump, it is easy to fix or rebuild, but may not hold up well with all that exposed metal. Likely a step above the RV models in most new boats.

I would look at the entire system, and see what annoys you the most about what you currently have? Running is a thing that pumps do, and unless you have a 100% system, even the new style pumps/tanks are going to run at odd times. The new style pumps are poorly mounted, and unless you need to know (by the vibration they pass to the rest of the boat) they are running..I would put some work into better mounting the pump you have. I would perhaps put $50 in to an accumulator tank.

The postpone the rest until you are ready to do the whole system. Then get red and blue PEX and sharkbite connectors and design, layout and build your own system. PEX isn't too bad, but the connectors are pricey, but will outlast the gray RV lines you probably have now.

JimsCAL · #3 (**permalink**) 12-17-2011

Hard to believe a system would be put together without a pump that start/stops automatically. What you have sounds very inconvenient. You could add a pressure switch to your current system, but that might cost as much as a new pump with that built in. Without an accumulator, the pump runs every time a faucet is opened. And if your system is not completely tight, it will start periodically (especially annoying when trying to sleep!). I would either add a pressure switch or change out the pump and add a small accumulator.

Sabreman · #4 (**permalink**) 12-17-2011

I think that the Par can be retrofitted with a pressure switch. I can't see the image on my iPhone to verify your setup. I rebuilt my Par with a new switch ant works great. Par also sells an inexpensive accumulator but with that said, I disconnected mine years ago to simplify my system.

Sabreman · #5 (**permalink**) 12-17-2011

I can see the pic now. Same as mine. Super reliable. DON'T get rid of it! Fix or upgrade. The reason so many manufacturers don't install this pump is because it's expensive.

Ritchard · #6 (**permalink**) 12-17-2011

For the record, the picture is not my pump, it is a web shot I found of something quite similar. I think that for the interim, I will install an expansion tank, that will at least allow me to pressurize the system to the point that you would get many gallons of flow from one use of the pump. The switch for the pump is on the panel quite near the galley sink, so it's not that bad, or rather wouldn't be with maybe the expansion tank in the system. Maybe I'll also re-mount the pump so that it is not quite so noisy.

Perhaps in the future then, I could find a pressure switch. Where would you get one?

billyruffn · #7 (**permalink**) 12-17-2011

We use a variable speed pressure sensing pump (PAR or Jabsco, I can't remember) and no pressure accumulator. It works well and is a no brainer to install. A variable speed pump delivers only the amount of pressure that's being demanded -- turn on a faucet with a slight flow and you'll hardly notice the pump is on. Doing the dishes while someone's in the shower and the pump will run continuously. The current system replaced one with an accumulator tank and a pump with a pressure switch (on at 5#, off at 15-20#), which also worked well. Removing the accumulator gave me more space in a head locker and the new pump is a lot quieter -- so quiet in fact that I wanted to install an indicator light to let me know when it was "on".

The only problem with pressure fresh water is that you'll use more and will be filling the tanks more often. Even so, pressure systems sure beat a foot pump for convenience.

The variable speed pressure sensing pumps are more expensive, but by the time you buy the accumulator and a "on-off" pump with a pressure switch, my guess is you'll be close to the same total cost.

Capt Len · #8 (**permalink**) 12-17-2011

The pump you show comes in two sorts One is for bilge pump. big flow low pressure. The other is for pressure systems. Normally would would have two screw in sensors in the base. One is pressure high /low switch usually set for 20 psi Other is low water off switch and needs to be manually bypassed with jumper wire until system comes back up to pressure from refilled tank. You can't have too big an accumulator. larger just allows pump to build a volume and not cycle so often. Accumulator should be T'ed in down the line a ways from the pump so pulse refection doesn't cause the pressure switch to stutter.Those were the Cadillac unit in their day but expensive and RV types are the easyier cheaper way to go. But noisy so mount on a plate that is soft mounted and keep on hand spare pressure switches . Any of these pumps appreciate not being left for long time with pressure on their diaphragms .

Minnewaska · #9 (**permalink**) 12-17-2011

I have a Shurflo smart sensor pump. It cycles on and off at variable speed to maintain pressure, which is as strong as at the house. At $165, it's a pretty good solution. I wonder what an accumulator tank and required fittings will cost.

http://www.amazon.com/SHURflo-5900-0.../dp/B000BGM326

Ritchard · #10 (**permalink**) 12-17-2011

Quote:

Originally Posted by Capt Len

The pump you show comes in two sorts One is for bilge pump. big flow low pressure. The other is for pressure systems. Normally would would have two screw in sensors in the base. One is pressure high /low switch usually set for 20 psi Other is low water off switch and needs to be manually bypassed with jumper wire until system comes back up to pressure from refilled tank. You can't have too big an accumulator. larger just allows pump to build a volume and not cycle so often. Accumulator should be T'ed in down the line a ways from the pump so pulse refection doesn't cause the pressure switch to stutter.Those were the Cadillac unit in their day but expensive and RV types are the easyier cheaper way to go. But noisy so mount on a plate that is soft mounted and keep on hand spare pressure switches . Any of these pumps appreciate not being left for long time with pressure on their diaphragms .

This is great info, Capt Len, thanks.