I am having a problem with my fresh water system freshwater pump

[motion30]

I Have a Jabsco dual pump and accumulator system. I have been away from the boat for a while and when I first returned all was operating normal. Now I have very low flow and lots of air coming from the faucets. at first I thought I had a leak in the supply piping but can find none. Then I noticed while the pump is running it seems to be pushing air back into the fresh water tank and the hot water heater. Looking for suggestions where to start to diagnose the problem

 

[Bruce B]

I'd wager that you have something stuck in one of the check valves of the pump.
Diaphragm pumps rely on check valves to control the direction of flow in the system.
I have successfully cleaned them by carefully taking them apart and literally cleaning up any contaminates but it is usually easier to simply replace them.
The pump has a manual, usually these have a parts breakdown and you can identify the checkvalves there.
You might use this opportunity to check the water strainer that is/should be installed in the hose that supplies water from the tank to the pump. You might be surprised at what resides there...
Bruce

 

[Steve]

Sorry, but, I have to ask how is the water level in the tank?

 

[motion30]

Steve. not an unreasonable question. The tanks are 2/3 full

 

[markpierce]

Haven't had a problem yet (knock on head). A slow drip-leak was corrected by tightening a nut.

 

[motion30]

Haven't had a problem yet (knock on head). A slow drip-leak was corrected by tightening a nut.

Very clean Installation. what does the big cylinder on the right do? Is that also an accumulator

 

[ulysses]

Could be sucking air from inlet side anywhere from the tank to the pump. Could also be a pin hole in the Diaphragm, my father said that is how I came into this world.

 

[Arctic Traveller]

Check the suction filter for restriction, and look for any crushed or kinked supply hoses, and are you really sure the tank is 2/3 full? How do you determine that, with a sight gauge, mechanical or electrical gauge? Only a sight tube is totally reliable, other gauges can fail. Can you see into the tank?...

 

[RT Firefly]

Greetings,
Mr. u.

 

[Fletcher500]

Could be sucking air from inlet side anywhere from the tank to the pump. Could also be a pin hole in the Diaphragm, my father said that is how I came into this world.

Good one.

Op, I am chasing the same exact problem. Keep us posted.

 

[hmason]

The pump may have lost its prime. Suggest filling the tanks to the top and be sure tank shut offs are both open. If there is an inline water filter remove the bowl and fill it with water then reattach it. Open a faucet and turn on the pump. Let it run for a couple of minutes and the open faucet should start sputtering and then begin to run. Suggest you only open the cold water side of the faucet until the prime is re-established. Then open the hot side. May start sputtering again if the hot water heater is empty. Be patient. Good luck.

 

[markpierce]

Very clean Installation. what does the big cylinder on the right do? Is that also an accumulator

That's an air reservoir for the loud air horn.

 

[Capt.Bill11]

I Have a Jabsco dual pump and accumulator system. I have been away from the boat for a while and when I first returned all was operating normal. Now I have very low flow and lots of air coming from the faucets. at first I thought I had a leak in the supply piping but can find none. Then I noticed while the pump is running it seems to be pushing air back into the fresh water tank and the hot water heater. Looking for suggestions where to start to diagnose the problem

Have you asked Jabsco?

 

[ksceviour]

Have you tried eliminating some of the system? Put the inlet line from the pump into a 5 gal pail of water and see how it draws. This could eliminate the pump entirely and isolate the issue to your supply line

 

[guy with a boat]

Most likely is your pump died. Cheap and easy to replace.

Second most likely is an air leak in the line before the pump.

 

[johnma]

Before you start to tear things apart looking for problems, unscrew your fill cap and try to run the system again. If the air vent line for your tank is clogged (dirt, spider nest, etc) you will get this issue. If the problem goes away with your fill cap off back flush your vent line. I teach hydraulic troubleshooting to some of the largest construction companies in the country and the first thing I tell mechanics is when the hydraulic pump makes a rattling sound, the hoses jump and you have low flow is to remove the fill cap for the reservoir. It's not always the problem but you will feel like a fool if you spend hours changing components and hoses and the boss walks over and loosens the fill cap and the problem goes away. Pumps don't suck fluid into them. The spinning motion creates a partial vacuum at the inlet and atmospheric pressure working on the surface of the fluid in the tank pushes the fluid into the pump. Many of you may already know this but it could be helpful info to some.
John

 

[ksceviour]

Before you start to tear things apart looking for problems, unscrew your fill cap and try to run the system again.

An excellent suggestion. I recently had a serious odor problem aboard that was eventually traced to a plugged vent line.

 

[FF]

Some of the "modern" FW pumps attempt to even the flow by bypassing the output .

This costs energy but folks seem to like the non pulsing flow.

Perhaps a chunk of crud has blocked the bypass open?

Folks that care about DC consumption might consider a largeer (2 gallon) accumulator and dumber pump.