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

[motion30]

I hhave been off the boat a few months when I returned the Water Systems seem to be working okay and then it started acting up. I have a fairly expensive jabsco duel pump and accumulator tank system. the problem is I have very low water flow and lots of air in the. I also noticed that when the pump is running it is pushing air back into the fresh water tank and the hot water heater. I have checked the piping from the fresh water tank to the pump and could not find any leaks.has anybody experience a similar problem.? there has been no changes to this system either electrical or Plumbing wise before this problem started

[Fiveslide]

Do you have any filters on your system? When I had similar symptoms, I had a small crack in the filter housing. It didn't leak, it sucked air in.

[meridian28]

The pump has a check valves that could be stuck

[Privilege]

When left idle for a while, the output side of the pump can fill with air, preventing the pump from pushing water where it belongs. Try opening the highest, or all of your taps and set the pump running. Once the water flows freely, close the taps and everything should work OK...hopefully.

[skipgundlach]

Set up a bucket with short ended hoses to check cycling.

If your bucket is near the level of the pump, you should have no issues about cavitation (we have to entirely depressurize our system before changing tanks, AND, sometimes, even, bleed it [crack open the pressure side] before it will pick up again]).

We proved a leak present (cracked nut on a plastic fitting) by that method.

So, back to the setup. Run the pump with both ends in the bucket. You should have a strong flow on the pressure side, and no bubbles on the suction side.

The only possible way that I could see for bubbles (air) coming back into the source (tanks) would be for it to be reversed (wrong ends on the pump fittings).

However, air in the hot water tank (how did this manifest itself/do you know air got into the HW tank?), as it's midstream, even if it leaked, could only come from the pressure end of the pump.

And as air can't inject itself without assistance into a pressure stream, it had to come from the suction side.

That means that you will have to check each of your fittings and lines between your tankage and pump, unless letting it run for a while cures the issue (if you have a leak in the supply side, it won't ever go away).

Privilege's comment is right, but if you have a vapor lock equivalent, it may never prime; our pump is only a foot or so above our full tanks, but about 4' above the bottom of the suction lines, and thus has to suck pretty hard for a bit; if there's some pressure blocking it on the output, it won't go (thus running our faucet dry before re-starting the pump); very infrequently I have had to bleed it.

If you have a working check valve, you should be able to pressurize your system (whether or not it's spitting air) and have the pump stop - and then open the supply side fitting and have no more than a dribble initially before no water comes back.

We went through several pumps before getting sorted out; even expensive pumps have their limitations, unfortunately. Keeping a rebuild kit handy is a good thing, unless you have the $pace and pocket$ for entire spares (we did, courtesy of the PO, but we got spares kits, too, as some of those spares were DOA).

HTH

L8R

Skip

[Cheechako]

Originally Posted by meridian28

The pump has a check valves that could be stuck

^^^ This... if it's pushing back into the tank. Air in your system maybe? anyway to bleed from a high point?

[jpstevens]

I agree with Meridian. That pump has two check valves that can fail. You can buy a kit online to replace the valves.It's easy to do.

[captstu]

Most likely, you have a small air leak on the inlet side of the system - possibly a gasket or "O" ring dried out from non use.

Not real easy to find - you can shut off everything and apply a small amount pf pressure. I place a "T" on the inlet side of the air line that allows air into the tank as it drains. Pressurize one side of the "T" until a balloon attached to the other side expands part way. Seal the pressurize side of the "T" and wait.

If the balloon goes down, you have an air leak - find it by working your way through every connection and looking for the leak.

I've had to put 10 drops of food coloring in the tank to find the leak when it is very slow.

I don't think a bad check valve on the pump would cause the symptoms you are having - the outlet side of the tank should be just water.

One thing to check - if you have an expansion tank with a bladder, it have a leak - unlikely since it would soon be empty, but if you remove the pressure tank, cap the outlet, and the problem stops, you found the problem.

[Oceanride007]

Sounds like your pump is fine, but could have a bit of crap under one of the kinghorn valves, if you have had the pump apart could be a "O" ring that has lost its bounce, easily replaced, get 2, same for any inline filter.
Sometimes if the pump has lost a little of its zip and the suction line has a few hills and valleys, that could be the problem, especially if the tank gets low.
Is the tank valve opened or is the tank empty.

[Mike Banks]

I had trouble with mine--it was noisy and poor output. I found that the bearing was crap--put a stainless steel sealed Japanese bearing in its place--works beautifully now. While at it I stripped the pump and replaced seals--and found a piece of plastic washer inside one of the pump chambers. I now use a garden hose filter in the inlet line to stop large particles, where I can get at it easily. Small particles pass through thepump eassily.

If you are using the electronic sensor type of pump which detects pressure drop--you do not need the accumulator and in fact those pumps work better without it. The earlier models use a micro-switch and diaphragm to dense pressure drop and switch the pump off when pressure rises again--and those earlier pumps work better with an accumulator--or so I have found. Pump the accumulator up to about twenty piounds pressure before starting the water pump. The pump puts out about fifty--so that willo give you some come and go and stop the pump hunting.

[sailorboy1]

If you have a tight system it may take a while for the dissolved air to get out the water. Every time you open the facet the air will strip out as the water depressurized. I just replaced my water pump a week of so ago and now everytime I get a glass of water it is full of air, but it is getting better. The old pump was back leaking to the tank and it didn't have the "problem", but then it ran more often instead.

[motion30]

Ok here is the final disposition of my problem. I put a clear plastic tube on the suction side and could see I had a small stream of air bubbles entering the pump. So with much effort I put new Plumbing between the freshwater tank in the suction side of the pumps. No change. previous to this I had the pumps apart and cleaned the valves. Found no debris. the final solution was a new pump. I bought two but as it turned out I only used one. I bought the pump online for Northern Tool it was a 5.5 gallon per hour 60 PSI pump. the pump cost $110 plus some assorted fittings that I needed. I remove the complete jabsco system which included two pumps and an accumulator. I now have more water flow and more pressure than I ever did with the Jabsco system.. thanks for everybody's advice ,problem solved now I can get back to buffing and waxing my Hull

[skipgundlach]

Thanks for the update. Got a link for us? Specs (amps, connectors, wiring spec, etc.)?

[motion30]

The motor is larger in diameter than the jabsco pump. They make a marine version as well but I wanted to use half inch threaded pipe fittings