Thank you everyone for your feedback and suggestions. Over the weekend I emailed the pump manufacturer "Rule" explaining my set-up and the problem it was having overcoming the check valve. I'll forward their answer below, makes perfect sense of course: Good day Don, Both Rule and our competitors' centrifugal style bilge pumps have very little air vacuum pressure because there is a large gap (depending on the pump, it could range between 1/16"-3/16") which allows high flow and some bilge debris to flow past the impeller without damaging the unit. The negative side of the having the large gap between the housing and the impeller is the impeller needs to come in contact with water to pull the water out of the bilge (water being a lot thicker than air). The check valve at the end of the bilge hose seals air in the hose and will not allow the water to come in contact with the impeller. The pump may be in a few inches of water (or completely submerged) but because of the air pocket, the pump cannot remove the water from the bilge. A generic remedy is to remove the check valve and put a curly-que (sorry for the lack of technical terminology) in the line and that will keep some of the water from flowing back into the bilge. Please let me know if there are any more questions, Michael Irving Rule Product Specialist ITT Marine and Leisure Group *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Don Lowther wrote: > Thank you everyone for your feedback and suggestions. > Over the weekend I emailed the pump manufacturer "Rule" explaining my set-up > and the problem it was having overcoming the check valve. I'll forward their > answer below, makes perfect sense of course: > > Good day Don, > > Both Rule and our competitors' centrifugal style bilge pumps have very > little air vacuum pressure because there is a large gap (depending on > the pump, it could range between 1/16"-3/16") which allows high flow and > some bilge debris to flow past the impeller without damaging the unit. > > The negative side of the having the large gap between the housing and > the impeller is the impeller needs to come in contact with water to pull > the water out of the bilge (water being a lot thicker than air). > > The check valve at the end of the bilge hose seals air in the hose and > will not allow the water to come in contact with the impeller. The pump > may be in a few inches of water (or completely submerged) but because of > the air pocket, the pump cannot remove the water from the bilge. > > A generic remedy is to remove the check valve and put a curly-que (sorry > for the lack of technical terminology) in the line and that will keep > some of the water from flowing back into the bilge. [snip] Sooo, in a nutshell ... it loses its prime, and the check valve on the _exit_ prevents it from getting air/water out? I'm wondering: "What's a curly-que?" Am I missing something? Wouldn't a check valve on the input side, and a free opening on the exit also solve the problem here, once the pump is primed? Or, is it the check valve on the input side that is the problem? -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Dave Kruger wrote: > Sooo, in a nutshell ... it loses its prime, and the check valve on the > _exit_ prevents it from getting air/water out? I could see this if the whole affair is pretty airtight. If air is trapped in the outlet pipe, inside the pump and the scroll case, water can't enter the scroll case to cover the impeller -- think of pushing an empty glass upside down into water - water stays out of the glass. However, I rather doubt that the whole affair is sufficiently airtight. If it is, a tiny hole in the pipe on the pump side of the check valve should solve the problem. That'll let air through but not leak any significant amount of water. > I'm wondering: "What's a curly-que?" If you make a full 360 degree loop with the outlet tubing, you get the equivalent of a trap in the drainpipe of a sink. If the top of the loop is close to the underside of the deck, it makes an effective check valve. If you can't find a cheap check valve, that's an alternative - not truly watertight, but pretty effective. I wish I knew about this before buying a $$ check valve. Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Michael Daly wrote: > Dave Kruger wrote: >> I'm wondering: "What's a curly-que?" > > If you make a full 360 degree loop with the outlet tubing, you get the > equivalent of a trap in the drainpipe of a sink. If the top of the loop > is close to the underside of the deck, it makes an effective check > valve. If you can't find a cheap check valve, that's an alternative - > not truly watertight, but pretty effective. I wish I knew about this > before buying a $$ check valve. Yeah, that solves everything, with no moving parts, no check valve to slow down water exiting the boat, and one less place for debris to clog the system. KISS wins again! -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Dave Kruger wrote: > Yeah, that solves everything, with no moving parts, no check valve to > slow down water exiting the boat, and one less place for debris to clog > the system. KISS wins again! But you still have a bunch of water holding back the air in the system. A tiny hole in the topmost position of the loop would solve that _if_ the air is really a problem. Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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