Bilge Pump Check valve Alternative?

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Ed

A good check valve can be found...

at a plumbing supply store. It should be at least twice as large as the hose, and made of solid bronze. ~ Happy sails to you ~ _/) ~ P.S. Put it on the bilge line if you want, or don't if you don't. I never told anyone that they must have it. However, others here seem to have no qualms about telling me that I should remove the ones I have. :^(
 
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Terry Arnold

pump screen backflow cleaning

A significant safety function of the water return after the bilge cuts off is that the return water acts to clear any debris that has been caught by the pump screen. With a check just above the pump, the return flow cleaning flow does not occur, clogging tends to be cumulative, possibly leading to a completely ineffective bilge pump operation. Anyway, the return flow would never constitute a significant portion of a bilge pump cycle volume under any ordinary combination of bilge line size and pump cycle bilge volume. No check for my boat!
 
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Ed

Terry: Speak for yourself.

In my case, without the check valve, the flow-back is enough to cause the float to turn the pump on several times, or to have it come on about every five minutes. Also, even with the check valve, when the pump shuts off - about two liters still flows back to the bilge, thus helping to unclog the pump screen. ~ Happy sails to you ~ _/) ~
 
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Tim

How about

A remote float switch that is mounted just above where the backflow level is. Won't switch on when you get backflow. Dual check valve in parallel? Or maybe a check valve with a manual bypass. Switch over if you get a clog. If not on your boat and she is sinking the bilge pump is useless. You could even set it up in such a way that switching to bypass unclogs the valve. I think some have lost sight of the original post. Forget your opinions and start thinking of better ways. No one is right or wrong. There will never be an agreement on opinion because people sail different boats with different needs. Tim
 
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Terry Arnold

Specifics of your system ED?

Ed, I notice that with 2liter return downstream from your check your check must be quite a ways up from the pump. (For a 1" line, it would be about 13 feet from pump to check and for a 3/4" line about 29 feet. How about sharing the geometry of your particular installation.
 
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Ed

Actually - No.

Keep in mind that the check valve does not close instantaneously. It takes probably a liter just to force it to close. So at least a liter returns to the bilge. There's probably another liter that just doesn't get pumped out, so that accounts for the two liters in the bilge when the pump stops and the back-flow returns. The check valve itself is rather large, and about a meter from the pump. The length of hose from it to the discharge hole is probably another four meters plus a bit for the anti-siphon loop. ~ Happy sails to you ~ _/) ~
 
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David Foster

Thanks for Sharing

I've read it all, and, as a result, put aside any idea of a check valve in my bilge line. I also learned that the right way to accomodate two pumps is two indpendent lines. Discussions like this probably get 10 readers for every poster. (That's about my ratio, anyway.) So I appreciate guys who maintain their positions, and back them up as Ed and David have. (Ed, I don't think anyone is telling you what to do. Instead, I think, like you, the others are backing up important points in an important discussion. Boats _are_ sunk by unpumped flooding of the bilge while the owner is away!) The clincher for me, by the way, is the ABYC position. That's because I believe they are an institution that does it's best to accumulate the hard lessons learned over years of boating mishaps. David Lady Lillie
 
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Carl Lebo

Plumbers Opinion

Not sure if it applies to boats but, when we install sump pumps or sewage ejectors we are required to drill a small hole just above the pump and below the check valve in the dicharge line. This allows the pump to accelerate up to full rpms before taking on the head pressure of opening the check valve and the weight of the water above it. It also can save a pump if the discharge lines becomes blocked as it allows it to operate albeit aat a much increased pressure. Pumps not installed this way do not last nearly as long and are not covered under warranty.
 
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Peggie Hall/HeadMistress

The difference is...

The pumps you describe are pulling water through them from above...bilge pumps push water from below. As I've followed this thread, one question keeps coming to mind: why not simply open the hatch and remove the water left by the bilge pump with a manual "dinghy" pump and a bucket at the end of each weekend? I did that for years...just part of the closing-up-the-boat routine that takes all of 10 minutes. Accessibility can't be the reason...if you can get to the area to install a check valve in the line (which I consider dangerous), you can get to it to pump it out.
 
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Ed

Peggy: Water gets in when I'm gone.

The bilge keeps accumulating water even after the boat is all closed up. I don't have a dripless prop-shaft seal, and there is some rain intrusion into the boat (which I will tackle someday). Also, I suspect there may be some condensation as well. In any event, even if I clean the bilge till it's bone dry, after a week it looks like there's another gallon in there. I don't know if the pump has come on or not during my absense, but it works when I'm there. ;^) ~ Happy sails to you ~ _/) ~ BTW, I don't think good quality and properly installed check valves are dangerous. In fact, to me they make good sense.
 
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Peggie Hall/HeadMistress

Two suggestions:

1. Fix the rain leak. Wherever the water is getting in, it's highly likely that it's not going directly into the bilge...and there's a strong possibility that not all of it ever gets there. Neglected leaks lead to anything from water stained headliners to structural fiberglass rot. If you've paid any attention at all to the number of posts from people who've looked at used boats with rotten mast supports, soft decks etc, you have to know what they do to the resale value of a boat. 2. Tighten the stuffing box--it shouldn't leak when the boat's at rest without the shaft turning, only when it is, to prevent dry friction heat from burning the flax packing. Cure those two problems and your bilge should stay dry when you're not around.
 
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Ed

Thanks for the advice.

I think I know where most (maybe all) the rain leaks are coming from - one portlight over the stove, and some adjacent screw holes for the headsail adjustment rail. They only occur during a hard rain from the starboard side, which lately has been nearly every other day. :^( The stuffing box is on my upcoming "do list", along with several other items. As you probably know, the bilge on a Hunter 34 is not very deep, and does not hold much water. It seems that two gallons will cause the float to activate, and (with the help of the check valve) all but about a 1/2 gallon gets discharged. Without the valve, only about a 1/2 gallon gets discharged, the rest goes up the hose, then comes right back when the pump stops. Thanks again for the advice. ~ Happy sails to you ~ _/) ~
 
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