CD30 electric bilge pump installed, BUT...

[Jim Adams]

I ran the hose to follow the existing 1 1/2" hose for the manual pump. Problem is that when the pump stops (has an attached float switch) the water rushes back into the bilge. Which, of course, makes the pump start again, stop, start, stop, start, etc.

Would the solution be to install a vented loop at the high point where the hose turns from coming up through engine compartment into the cockpit locker? And/or raise the float switch an inch or so?

The pump has an 1 1/4" outlet which I ran for a foot then switched to 1 1/2" hose...was this a mistake? I hope not because I've already installed a 1 1/2" thru-hull!

Jim Adams
Lauren Leigh
CD 30 Houston, TX



jamespadams@yahoo.com

[Chris Cram]

Jim, More experienced members of this board will weigh in but, let me ask did you put a check valve in the line? This allows water to go only one way. It is usually a little piece of plastic pipe with a ball inside that is forced backward when water retreats back down the hose then closes the aperature preventing back flow. I have one of these.

Chris Cram
CD 30 C



cccobx@prodigy.net

[Jim Adams]

I was advised by members of this group and by a couple of articles on Sailnet that a check valve was a bad idea. It supposedly restricts flow. But if you have one and it doesn't cause problems maybe that is the way to go. Thanks for the idea.



jamespadams@yahoo.com

[Chris Cram]

Well it hasn't been a problem yet but I can see how it would be especially if the pump picked up some sort of matter out of the bilge. The other thing is the exhaust hose is supposed to have a significant rise and fall (a loop) to act as a trap.

Chris



cccobx@prodigy.net

[Jim Adams]

I tried contorting the hose into various rise/falls to no avail.



jamespadams@yahoo.com

[Hobby Marine]

Jim: There are two main types of check valves. A Ball Check and a Swing Check. If I install a check valve I use a swing check valve. There is less restriction to flow. If you install a check valve, you should check the operation from time to time. Crud in them will keep them from closing tight and could block the flow when needed. A vented loop would keep the water between the vented loop and the drain from draining back into the bildge. The water between the loop and the pump would drain back into the bildge.
Good Luck.



Info@hobbymarine.com

[len]

jim

i am probably one of the people who gave you the idea not to use a check-valve - you can't rely on check valves the way you rely on sea-cocks but you can safely put a check valve in the hose near the pump to prevent the problem you describe - it you are concerned about flow, you can step up the hose to a size larger, have the check valve, and then step down again to rejoin the original hose

len



md.frel@nwh.org

[Larry DeMers]

I currently have the same backwashing of some of the bilge effluent. It isn't enough to cause the pump to short cycle like yours, but it doesn't give me the nice dry bilge sump that I like. So I am going to try the vented loop trick. Maybe mount it highas possible, and as close as possible to the pump, so that once the suction is broken, all that will rush back into the bilge is the water from the length up to the vented loop.
This vented loop will work here..but will not work with the manual bilge pump, mounted at the transom, as it will just suck air from the vented loop's ball valve.

I would still not recommend using a check valve in the pump output line.

Cheers!

Larry DeMers
s/v DeLaMer
Cape Dory 30

I ran the hose to follow the existing 1 1/2" hose for the manual pump. Problem is that when the pump stops (has an attached float switch) the water rushes back into the bilge. Which, of course, makes the pump start again, stop, start, stop, start, etc.

Would the solution be to install a vented loop at the high point where the hose turns from coming up through engine compartment into the cockpit locker? And/or raise the float switch an inch or so?

The pump has an 1 1/4" outlet which I ran for a foot then switched to 1 1/2" hose...was this a mistake? I hope not because I've already installed a 1 1/2" thru-hull!

Jim Adams
Lauren Leigh
CD 30 Houston, TX

demers@sgi.com

[Bob Zemore]

Don Casey (This Old Boat, pp.280-283) has a solution. Install two bilge pumps, a small 400 gph pump with integral float switch connected directly to the battery, fitted with a half-inch discharge hose, and a large 3500 gph pump fitted with a 1 1/2" hose and set above the smaller pump. The small pump handles the small spills, and because it is discharging through a 1/2 inch hose rather than a 1 1/2 inch hose, the amount of water draining back into the bilge is reduced by 89 percent.

I haven't tried this yet, but it is definitely on my list of projects for this year.

-Bob Z.
CD 330

I ran the hose to follow the existing 1 1/2" hose for the manual pump. Problem is that when the pump stops (has an attached float switch) the water rushes back into the bilge. Which, of course, makes the pump start again, stop, start, stop, start, etc.

zemore@worldnet.att.net