Need help with freshwater system

[Senorjacob]

Hi folks,
I’m so grateful for this resource and all the sound wisdom to be found on this board. I’ve done some searching around but I can’t seem to find an answer to my problem.

Basically my freshwater pump doesn’t work. I’ve filled up the tanks and turned on one water tank at a time through the ball valves in the bilge. I’ve cleaned out the inline filter, but I can’t seem to get the water flowing. Randomly it started working a few days ago, but I couldn’t tell you what I did. I see water through the clear hose that’s connected to the water pump, and the filter has water in it. But no matter how long I run the pump, it just doesn’t seem to “grab” the water and force it up.

I have only one tank open at any one time. I’ve tried keeping the faucet’s closed, and I’ve tried keeping them open. I’ve also tried shutting off the manual pump as well.

Has anyone had similar problems?

Thanks in advance.
Jake

[mgphl52]

Maybe a dumb question... but, is it possible that tank vents are blocked and not allowing air in?

[Senorjacob]

It’s possible. I’ll check that. But when the system was working I was drawing from the forward tank and now that it’s not working I’m also drawing from the forward tank.

[mgphl52]

Maybe you "drew" all of the free air from the tank? Of course, I think that would only happen if the vent was completely closed/blocked.
On my CD28 the tanks have inspection accesses. If your tanks have such, try opening them and then see if you get pressure water,

[Steve Laume]

If there is even a tiny leak on the suction side, the pump will not function properly. Look for bubbles on the intake side and check the connection to the pump, Steve.

[bottomscraper]

And to follow on to what Steve said...

If the "manifold" where all the separate tank valves are connected is of typical CD construction, the hose is clamped on a piece of straight copper tube. On Mahalo this was a constant source of air and water leaks. I replaced it with a new manifold assembled using proper hose barbs for the hose connections and quarter turn ball valves.

Another problem may be the pump itself. Water tank crud can prevent the internal check valves from working correctly.

[Keith]

Try short piece of hose into a bucket or water connected to the input line of the pump. this will confirm if the pump is the problem.

Keith

[Senorjacob]

Great! Thanks for all the suggestions. I will check for air leaks and also take a stab at pulling apart the pump.

Jake

[David Morton]

My pump, a Jabsco 36950-2, on my CD31 gave me similar problems. Though there was no leak, I had to prime the pump by connecting a raised bucket of water to the intake hose of the pump. Eventually I rebuilt the pump, replacing the diaphragm, and now all is well and it no longer requires priming. It was an easy fix. Toughest part was getting the pump out of the boat, as is typical with just about everything on a sailboat!

David

[Paul D.]

What is the pump type? If you rule out the suction side hose leaks and suspect the pump, and the pump is an impeller type, the O ring seal may be letting just enough air in to prevent it working properly. I had that issue with an old Jabsco bilge pump.

My original freshwater pump actually is similar to the original bilge pump, shown in the link.

https://www.wakemakers.com/jabsco-balla ... hAQAvD_BwE

Good luck,

[Senorjacob]

The previous owner left several replacement impellers on the boat. The pump had been working for awhile now so I’m wondering if it just had to work out the air. If it happens again I will pull out the pump and take a look.

[wikakaru]

Another possibility could be that you have high spots along the intake line where air can get trapped. Ideally you want a continuously upward sloping curve from the tank fitting to the pump so that air bubbles cannot be trapped in the intake line. If that's your problem it will recur every time you run the tank dry and suck air into the system.

[J Stevenson]

I would expect the pump to be a diaphragm type.
I replaced the diaphragm and the check valves on ours after the pump got to the point of not working reliably in
the process of switching from one tank to another.
It is an easy fix once the pump is out.

[Senorjacob]

It's a Flojet.

[J Stevenson]

Exploded view of parts:
https://www.pumpvendor.com/Flojet_04405-143_parts.html