Plumbing issue with water pulsing from foot pump outlet

[peaman]

I have the common arrangement of a foot-operated fresh water pump serving a dedicated outlet at the galley sink, along with an electric pressure pump which serves the house plumbing including a conventional faucet set in the galley as well as one in the head. When using water in the usual way from the pressure pump, there is always flow from the foot pump outlet in the galley.

The electric pump is a Shurflow Aqua King II, which is a pulsing type pump. The foot pump is a Whale Gusher Galley. Both foot pump and electric pump draw from the tank manifold, as they should.

I think my plumbing arrangement is pretty common, but I would like to think there is a good solution for reducing or eliminating the waste of fresh water from the foot pump outlet as a result of pressure pulsation from the electric pump. For example, is it common to have a check valve before the pressure pump?

Any thoughts?

 

[Christian Williams]

So when you run the pressure water, there is flow from the foot pump tube (vent, outlet)?

I have not seen that. Usually the pressure system and the foot pump are independent.

My guess is that the foot pump is old and needs to be replaced. Not uncommon after all these years.

 

[Nick J]

I had the same problem. I think what's happening is the suction from the electric pump is pulling on one side of the foot pump bellow and when the pump cycles off the bellow goes back to neutral by pushung out a small amount of water. I think the original configuration on our boats of the manual pump being teed off the main line to the electric pump makes it a little worse because the foot pump is the closest source of flex in the system.

When I replaced the plumbing in my boat, I put a manifold next to the water tank and took a dedicated line from the manifold dirrctly to the foot pump and another for the electric pump. This fixed the problem for us.

 

[Christian Williams]

Here's the manifold on my 32-3. The center valve allowed the single foot pump to be set to salt water if desired, for galley sink cleanup to save drinking water. I don't know if it was factory, the install might well have been subsequent.

 

[peaman]

Like yours, my foot pump is connected to one end of the tank manifold while the electric pump is connected to the opposite end. I have separate salt and fresh foot pumps, and the fresh foot pump is only one year old. It pumps well, as expected, so high confidence in that. I guess the pulsations from the electric pump are forcing back flow through the foot pump in a variation of "water hammer". Barring better insights, I will consider installing either a water hammer arrestor or a check valve in the electric pump suction hose.

 

[Christian Williams]

I had pulsations, which sounds like a 911 call but in fact was result of a nonfunctioning accumulator. I replaced it and now the stream is steady, and I am back to a normal pulse rate.

 

[peaman]

I could swear that an accumulator was advised against when I installed my current pump. I can't find that reference, but the pump it replaced, which is similar to the one in your image advises "For proper shutoff, remove accumulator in system." That didn't make sense to me, but as the boat didn't previously have an accumulator, I didn't think further about it.

What accumulator might be a good choice for a 32-3?

 

[Christian Williams]

See the middle of this blog. I imagine same as the 381.

E381 - Macerator and Accumulator Replacement

Ericson 38 sailboat head plumbing macerator replacement Christian Williams Thelonious II

ericsonyachts.org

 

[Elrod]

Late to the conversation. Have same set-up…just replaced the Shurflo pump and last year replaced the two whale gusher foot pumps. The Shurflo pump has two adjustment screws; one for pressure and one for a check valve that apparently allows backflow when a a faucet is shut quickly. I was disappointed in the instructions with the Shurflo pump as there was not even an illustration indicating where the adjusting screws were or which was which. Perhaps your check valve setting is too low allowing back pressure into the manifold? I read several reviews of the pump where purchasers had to fiddle about with the settings to get the pump working correctly. Personally, did not have problems like theirs or yours. (My problem was eliminating air leaks into the system on the draw side of the pump…..that little sucker draws well) Good Luck if you have not already solved it.

 

[peaman]

Installed a new accumulator, Jabsco “mini” 21.5 oz, and it makes a big difference. The foot pump outlet still squirts sometimes when the pump shuts off, but that is much less frequently and much less volume. The pressure water can run for a while before the pump needs to catch up. Overall, using the fresh water is much more civilized. It is surprising that there was apparently never an accumulator before now. No adjustment to pressure settings were needed at this time.