Auto ballast priming issue "Drain"

[jibmaster145]

Over the weekend I plumbed in my ballast bags and ran into a problem. Filling the bags everything works great but as soon as I go to drain the bags I can’t get the drain pump to prime.

I connected everything so I would only have one line on each bag and be able to fill/drain each bag with the turn of a couple ball valves.

The ballast bags are both located above the pumps so I wouldn’t think they would have a problem priming with the help of gravity.

The pumps are Attwood 800gph and are mounted horizontally with the outputs facing about 45* down. Is the angle of the outputs causing the priming issue or am I missing something? I haven’t had a chance to adjust the pumps to angle the outputs up and see if this will fix the problem.

I attached a diagram of how I have the bags plumbed. Any input would be appreciated.

[ski4evr]

Probably a dumb question, but did you hook the lines up to the bottom of the ballast bags? If hooked up on top, could be an air pocket trapped in bag.

[jibmaster145]

Probably a dumb question, but did you hook the lines up to the bottom of the ballast bags? If hooked up on top, could be an air pocket trapped in bag.

I did have the lines hooked up to the top. When I was filling them I tried to vent all the air out of the bags. I was worried if I tried to fill from the bottom the pumps wouldn't create enough pressure to fill them.

I will try filling from the bottom next time and see if it helps. Thanks for the reply.

[High altitude]

I hate to say it, but you might want to consider impeller pumps instead of the Attwoods. I had too many issues with the Attwoods not priming so I finally switched. Best move I ever made. I went with Johnson pumps and couldn't be happier. I think if you ask around, you will find a lot of similiar stories with the Attwoods. -Marc

[Mikeski]

I hate to say it, but you might want to consider impeller pumps instead of the Attwoods. I had too many issues with the Attwoods not priming so I finally switched. Best move I ever made. I went with Johnson pumps and couldn't be happier. I think if you ask around, you will find a lot of similiar stories with the Attwoods. -Marc

+1

[thedude]

Filling/draining from the top of the bag may be creating a air pocket which the Attwood pump can't overcome unless you constantly put pressure on the bag to force water up into the hose. If you want to stick with 1 pump you will probably have to go with Impeller pumps plumbed to the bottom of the bag. Or you could rig up a second Attwood pump to the bottom of the bags for draining purposes. It is a good idea to install a vent line with a check valve as well.

[MLA]

Any aerator live-well pump will need to be connected directly to the water source. In other words, below the water line, whether its the fill pump located in the bilge or the drain, mounted right on the sac. For a 2-sac setup, you will need to add a 2nd T800 and locate each drain T800 directly to the sacs. They can be run to the same switch and the drain lines can be tie together, but 2 drain pumps is needed.

Or, swap the two aerator pumps for a single reversible impeller pump. This would be the simplest reconfiguration and probably the most effective. You pump the ballast water right back out the bottom of the boat through the pickup.