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Old 06-04-2010, 08:29 AM   #1
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Bad bilge pump?

Think I have a bad bilge pump. It spins and pumps water when not connected to the discharge hose. The hose is clear, because I just blasted water through it with a hose. However, when I hook the bilge pump up to the hose, it just won't pump water through it. It used to... maybe the impeller is damaged?
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Old 06-04-2010, 10:58 AM   #2
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RE: Bad bilge pump?

Do you have a check valve in the discharge hose? Seems like the plastic impeller would be pretty hard to tear up!
My shower sump is just a Rule bilge pump and it has air locked before.
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Old 06-04-2010, 12:03 PM   #3
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RE: Bad bilge pump?

Yes there is. I've had this problem intermittently before. Now this morning, I left it* running and when I came back, it had worked again! Think I should just ditch the check valve, or drill a small relief hole as some have suggested?
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Old 06-04-2010, 01:09 PM   #4
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RE: Bad bilge pump?

Chuck it in the trash can !! If it quit once it will quit again and who knows, maybe that time you will really need it to pump.
Small price to pay for the peace of mind.

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Old 06-04-2010, 08:10 PM   #5
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RE: Bad bilge pump?

Rule specifically warns against a check valve.* They tend to get a little corrosion and will readily stick.* The design of the Rule type bilge pump will put out a lot of water, but not against any kind of a head.* If it's a flapper valve, you should be able to unscrew the pin from the outside after removing the cap nut and disable the thing.* If a spring check, you have to remove it.* Make sure you put in an anti-siphon loop if you remove the check....
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Old 06-05-2010, 04:40 AM   #6
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RE: Bad bilge pump?

A check valve is usually used because the hose run is so long the water filled hose will refill the sump the pump is in , and short cycling is the result.

A shorter overboard hose or raising the pump operating float level will work.
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Old 06-05-2010, 09:14 AM   #7
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RE: Bad bilge pump?

I think I'm just going to get a new pump and put a new hose in minus the check valve. This is a dry sump anyway under normal conditions, but when the shower sump fails it overflows. I'm going to replace that with a whale diaphragm pump too.
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Old 06-05-2010, 09:33 AM   #8
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RE: Bad bilge pump?

I have a Whale diaphragm pump. Love it. No more hair clogs. If fact I keep the dog away from it for fear that it might get pumped overboard.

When it is pumping over the side get used to passerbys asking what the pulsating water stream is that is coming out of the boat.
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Old 06-06-2010, 03:58 AM   #9
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Bad bilge pump?

IF you will be doing wiring, a second float switch a few inches above the primary wired to a BELL , might wake you or the locals to a problem.

A bell will still ring with a battery too dead to run the pump anymore.

The Whale pumps work best when gravity fed with water, as a lift pump for getting rid of waste at sea there very poor as the valves do not seal with tiny trash* that hardens in place..

-- Edited by FF on Sunday 6th of June 2010 04:01:01 AM
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Old 07-08-2014, 04:37 PM   #10
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Reviving this thread, as I have a very similar - maybe the exact same - problem, but I don't see a totally clear answer in any of the replies.

Here's my situation: shower has a small (1/2 gallon?) sump in the floor, with a Rule 360 gph bilge pump. (Model 24 - it's activated with an external switch, no automatic switching.) The hose goes from the bilge/sump, down about 18" (to go under a bulkead), then back up about 2.5 to 3 feet, to what is, I believe, and anti-siphon lock*. From there, another hose drops down about 18" or so to a thru-hull that's just above the waterline.

*I think it's an anti-siphon lock. It's an upsidedown "U" shape, about the size you would make with your thumb and forefinger. At the top of it is a screw-off "cap", and inside the cap is a small rubber piece that sticks down into the tubing of the "U" shape. I have a picture of it, if that would help.

Similar to one of the other posters: the pump pumps like mad when just in a bowl of water, with the pickup always submerged. The outflow hose is clear, as I can fill it with water and easily blow all the water out. But when the hose and pump are connected, none of the water flows out. The one exception: I had the hose and pump disconnected; I filled the hose with water; I put the pump in a bowl of water and got it moving that water around, but not sucking any air; then I very quickly inserted the out tube on the pump into the hose, and it emptied the bowl in a flash.

Oh - I also disconnected the hose from the anti-siphon lock - the hose that runs from the shower - and put the hose end into a bucket, then tried to pump water out of the shower. Still no go. At that point, the hose ran from the sump / bilge pump down about 18" then back up about 2' to the bucket.

So, I think the problem is that the pump works fine as long as there is no air getting into it, but as soon as you use it, it removes all the water from the sump and sucks in air, and then it stops working again. i.e., I don't think the siphon lock has anything to do with it. I think the problem is that the pump simply won't pump the water if it ever gets any air in it. And yes, I had a brand new spare pump that does exactly the same thing as the old one.

Do I need a different kind of pump? One that's specifically designed to be self priming, or something like that? The funny thing is, when I first started troubleshooting this problem, I discovered a giant wad of hair on the bottom of the pump, which had obviously gotten there over many, many showers during which the pump was almost certainly pumping the water out. So I'm pretty sure that, at some point, this system worked.

Even though my spare was new in the package, it's probably many years old. Should I just buy a new pump and try it?

Thanks.
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Old 07-08-2014, 07:25 PM   #11
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Brian, I'd bet that the impeller has spun on the shaft. When this happens the motor runs but the pump won't overcome the back pressure caused when the pump tries to move water uphill. The motor shaft is actually spinning inside the plastic impeller. The pump will often move water around in the bilge with the hose disconnected but won't push it up hill. The little Rule is cheap, just replace it.

The upside down U thing is a siphon break. It is designed to let air into the hose when the pump is off. This prevents a vacuum from forming and sucking water back into the boat.
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Old 07-08-2014, 08:44 PM   #12
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Quote:
Originally Posted by troy994719 View Post
Do you have a check valve in the discharge hose? Seems like the plastic impeller would be pretty hard to tear up!.
I had a bilge pump where the plastic impeller broke and came off the metal shaft. The motor ran fine but it didn't pump water.
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Old 07-08-2014, 09:31 PM   #13
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I bet the problem is the pump outlet hose going down below the bulkhead at the outlet of the pump. After sucking air, the air cannot purge properly. If you can temporarily re-route the hose continuousely upward slope to the vacuum breaker, the air can purge from the pump, develop discharge head pressure and it should pump out.
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Old 07-21-2014, 10:41 AM   #14
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I bet the problem is the pump outlet hose going down below the bulkhead at the outlet of the pump. After sucking air, the air cannot purge properly. If you can temporarily re-route the hose continuousely upward slope to the vacuum breaker, the air can purge from the pump, develop discharge head pressure and it should pump out.
I'm now convinced this is the problem - air gets into the pump and then it simply won't move the water. Problem is, this happens every time the pump comes on - it pumps until there's no water left, so it starts sucking in air.

I don't think there's any way I can route the hose so it goes only upward to the siphon break. If I could, that would solve the problem. So I either need a different kind of pump (one that won't fail if it sucks in air), or I need to install a float switch that will shut the pump off while there remains a little water in the sump, so no air can get sucked into the pump.

Thanks for all your input, everyone!
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Old 07-21-2014, 01:35 PM   #15
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Try this then:
Temporarily raise the float switch by putting a spacer under the switch with something like a 1/4-20 SS nut at each mounting screw. Leave the pump where it is. See if that makes a difference.
Plan B- If you can, make a small upward loop out of the pump disch hose a couple inches high before it has to go back down under. More would be better. If the air can move even a little out of the pump when it turns on, it will be replaced by solid water and develop head.
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Old 07-30-2014, 03:57 PM   #16
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Originally Posted by Penta View Post
Chuck it in the trash can !! If it quit once it will quit again and who knows, maybe that time you will really need it to pump.
Small price to pay for the peace of mind.

John Tones MV Penta
Sidney, BC
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Old 07-31-2014, 03:28 PM   #17
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Seriously though. I just had my fwd bilge pump hang up. Its a new boat to me so I ripped out the fwd and aft pumps w floats, plumbing and wiring and ran all new.
Peace of mind

I hope you find the problem though. Good luck
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Old 07-31-2014, 07:26 PM   #18
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High Wire - I'll try the Plan B - making a loop that goes above the level of the pump. Sounds like that might work!
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