Freshwater Pump Help!!!

[mvweebles]

Originally Posted by a64pilot

Which has me wondering about the isolation check valve. Have you tried it without the shore water connected and on?

Here is a decent diagram off West Marine - note location of check valve. This really is a simple system. If the check valve has failed and the dock-hose is connected, I'd guess it would create the the same symptoms. So I agree with a64 - disconnect the hose. After that, I got nothing,

[Thumbs Up]

"Isolating the accumulator isolates it as an issue as there was no change."

No, because the accumulator is already acting like it isn't there in the first place since no water can enter due to the fact that the bladder is pushed all the way up against the the inlet. The air pressure and bladder is meant to act as a spring. The pump pressure can't overcome the bladder pressure because it is overcharged with air and the tank stays empty which causes the pump to short cycle when you open the tap.

[a64pilot]

Originally Posted by Thumbs Up

"Isolating the accumulator isolates it as an issue as there was no change."

No, because the accumulator is already acting like it isn't there in the first place since no water can enter due to the fact that the bladder is pushed all the way up against the the inlet. The air pressure and bladder is meant to act as a spring. The pump pressure can't overcome the bladder pressure because it is overcharged with air and the tank stays empty which causes the pump to short cycle when you open the tap.

I’d agree, but he has tried two different accumulators with no difference. So either he has two bad accumulators, which is possible but unlikely, or it’s not the accumulator.
If it were the accumulator, I’d expect at least some change when they were replaced

[Thumbs Up]

Originally Posted by a64pilot

I’d agree, but he has tried two different accumulators with no difference. So either he has two bad accumulators, which is possible but unlikely, or it’s not the accumulator.
If it were the accumulator, I’d expect at least some change when they were replaced

But he didn't let any air out of either one. They come pre charged with a lot of pressure. You have to let some air out. They aren't defective.

[a64pilot]

Originally Posted by Thumbs Up

But he didn't let any air out of either one. They come pre charged with a lot of pressure. You have to let some air out. They aren't defective.

It used to work fine though, and he added no air. So if it was working fine, and then quit because it’s overcharged, how did it get that way?

As I understand the system was working fine and has been for as long as he has had the boat, then the pump started rapid cycling.
My latest guess is that the check valve is leaking and the pump “sees” marina water pressure and that is what is causing issues.
Because according to the attached diagram, and they way my RV was, when connected to a pressurized water supply, the pump and tank were out of the picture, bypassed

[Thumbs Up]

Originally Posted by Sojourner

Hi all, so we're stuck here on lockdown, when my Jabsco freshwater pump decides to crap out. It had been fading for a while, the accumulator tank needing pumping more often. Finally, no matter what you did, the pump would cycle on off on off every half-second or 1 second and pumped water, but obvs it was time to do something.

I got in a new accumulator tank just before lockdown, installed it. No change in the rapid cycling.

I luckily found a brand new jabsco pump of the same type in our spares, so I installed it. STILL CYCLING EVERY SECOND or even faster! Also, the green light indicating the freshwater pump being on stayed lit on the 24v panel, even when I turned the faucet off and the pump was silent. The old pump did not do this.

Here is a pic of the install. New pump, new accumulator. The install was a straight drop in, I had to connect two wires, that's it. Now I'm looking at this thing with the spring.... what is it?? It's attached directly to the accumulator tank and the power goes to it, but why the spring? The pressure regulator on these pumps is on the end of it under the blue cap.... could this be the issue?

What other thing should I be looking at? I have shore water for the moment, but I really need to fix this pump issue. Any help would be much appreciated!

The old accumulator wouldn't hold air, so would have been full of water. The new accumulator has too much air and water can't enter.

[a64pilot]

Originally Posted by Thumbs Up

The old accumulator wouldn't hold air, so would have been full of water. The new accumulator has too much air and water can't enter.

Possible I guess, I get from his description that the pump only rapid cycles when a facet is open, that means that with an open facet it’s hitting the pump cut off pressure, again possible I guess.
I used to maintain a fleet of aircraft, I wish I had a quarter for ever time we fixed an aircraft by replacing a part, but had given up on it being that part, because we had already replaced it once and it didn’t work, meaning of course that the first new part was also bad.
Particularly black boxes, so I started replacing with a “known good” box off of a working aircraft for troubleshooting, and then once in a blue moon it still wouldn’t work, because something on the broken airplane blew the known good box.
Hopefully he lets us know what it is when it get fixed.

[Chotu]

Sojourner: I think you have a typo in your thread title.


"Freshwater Pump Hell" was the appropriate title.

Sorry it's so frustrating. Just need to keep simplifying and isolating.

Try just the pump all by itself with no extra pressure switch and no accumulator. Just the pump hooked to 12v and the water supply. Then add stuff on until you find the issue. It's really the only way to keep your quarantine sanity.

[merrimac]

When it cycles off/on, does the pump make a loud KRRRRH KRRRH noise instead of a softer more "purring" noise?



In my experience, that is what these pumps do when there is a small leak on the suction side causing tiny air bubbles to be pulled into to the pump.


Had this for a while and like you it was maddening. Turned out I had a very very small leak on a filter between tank and pump: it did not let water out when the pump was off, but it did let air in to the hose when the pump was operating.

[Thebaysailor]

Sojourner. I deal with a lot of these pumps in off-grid cottages and now yachts.
As with most mysteries try first to isolate the problem.
In your case install a shut off valve directly AFTER the accumulator tank.
Turn this valve off. Now all issues are local to the pump.
Remove your accessory pressure switch, not needed, and install the wiring directly to the pump wires.
The pump should be connected directly to the accumulator tank, no filter, no check valve, nothing between pump and tank.
Be sure the arrows on the pump body are proper for your install.
Be sure any filter BEFORE pump is clean and properly sealed, no suction leaks.
If you are unsure then remove filter housing and run direct plumbing from holding tank to pump inlet for our testing.
Run pump and check performance. Pump should turn on and achieve pressure of 40 to 50 psi depending on model of pump and then shut off and stay off.
If this is working properly now open new shut off valve and check performance again. Locate any problems.

[In The Mood]

Often there is a filter on the low pressure side of the pump. Is this is blocked even slightly it can cause the cycling.

[SV__Grace]

Been following this thread with interest as my fresh water system has challenged me in the past. I could have missed them, but here's a couple of things I haven't seen addressed-

- Air in system might need to be bled

In my system, if I run a tank dry or change a water hose or anything else that might introduce air into the system, it won't return to normal until bled. Bleeding involves running faucets at both ends of the system with the pump going, alternately turning them on and off and listening for a change in pump behavior. PO installed a Y valve with a hose on one end to the pump outlet, and using that seems to make a big difference in bleeding.

-Might need to match cut in and cut out PSI of Accumulator tank and pump.

They are a team and work together. Be sure they're playing nice by pressurizing the Accumulator tank to match the requirements of the pump pressure switch.

[Beach View]

Sojourner,

Is your bilge pump cycling more often than normal? Are you topping off the tanks faster than normal? Have you taken the pump apart to look at the diaphragm?

Last summer I had a couple of things happening at the same with my water system, making it hard to track down exactly what was happening at any given moment.

1. My faucets & shower heads were blocked with calcification. I took them off and soaked them in “Lime Away” (a spray-on cleaning product I use on my shower every couple of weeks) for a while, cleaned with a brush and rinsed with clean water.

2. Scale was repeatedly blocking the little screen attached to the water pump inlet. This screen is barely adequate, so I installed a large filter and valve between the tank and the pump.

3. I noticed small pool of clean water in the engine room, tracked it down to a crack in the handle of the transom shower, replaced.

4. Sediment in the tank. After a couple of years using our clean (but extremely hard) dock water there was enough scale in the bottom of the tank to block the outlets—ultimately, I think this is what caused continuous cycling of my FW pump. Easy to tell if the tank outlets are blocked: Remove the inlet line at the pump. If the inlet line is clear I get a gush of water, but my tanks are well above my pump. A quick test is to blow into the line from the pump end until you hear bubbles (or suck on it and test the pressure it takes to pull water). Final fix was to take the tanks out (luckily easy on this boat) and rinse/clean with fresh water. Shocking how much “mud” came out. Mostly thin flakes, as if scale formed on the sides of the tank as the water level dropped, then flaked off later—thin and flat, perfect for blocking the pump screen. If you can’t take your tanks out maybe drain them down and add some acid, but I don’t know about the collateral damage from that…

I am still going to buy a spare pressure switch, but at least for now my FW system is working well.

Cheers,

Bill

[garychurch]

Problem is with the pressure switch adjustments. Please see

https://www.youtube.com/watch?v=LHUye0mykE8

. Been there and done that.

[Thumbs Up]

I am 99% sure that I solved this problem pages ago. Still waiting for confirmation from Sojourner. The new accumulator had too much pressure, the old one wouldn't hold any pressure. Simple to let some air out. That external pressure switch is not needed. The pump has it's own.