I think any diaphragm pump, like the Whale manual pump, has check valves built in.
Factory original bilge pumps in 32-3
- Thread starter peaman
- Start date
peaman
Sustaining Member
Correct. The diaphragm moves back and forth only to create the negative/positive pressure pulses, while a pair of check valves keep those pulses moving in the right direction. It is possible to push fluid right through a diaphragm pump, but only in the correct direction.
Right. Neither the diaphragm nor the centrifugal pump would, by itself, need a check valve. It's the Tee in the plumbing that requires it. Without it, the Rule can pump the wrong way through the Tee--i.e., out the open hose end that serves as the Whale Gulper pickup--rather than out the end connected to a through-hull (see the drawing in post #95).
Trickdhat came up with the brilliant idea of eliminating the Tee altogether and just letting the Whale pump suction through the open body of the Rule pump. That's so clever I'd have to give it a try. It might be restrictive though; the Rule pump's outlet size (at 1-1/8") is 44% smaller than the 1-1/2" hose the Whale uses.
If that is too restrictive, then what? I'd still find a way to eliminate the check valve (it renders a pump inoperative whether it gets stuck open or closed). Other options:
1. Unlikely, I'm guessing, that you'll find a centrifugal pump with a 1.5" outlet that will fit in the bilge.
2. Keep the Tee, but:
a) replace the check valve with a simple ball valve
or, b) ditch the check valve and just keep a threaded nipple and cap on the Whale's intake while it's not in use.
Also, hang a tag on the Whale pump handle that says "Open Y-valve and remove end cap (or, open ball valve) before pumping."
Never a "perfect" solution, but any of these beats tearing through the hull, sole, and TAFG to install a second 1.5" hose and thru-hull.
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Filkee
Sustaining Member
Okay, I go from feeling smart to not so smart and then it keeps me up at night. To reset, I have two Rule 500 Automatic (cycling) pumps. The previous owner wired them toget her and they share the switch in the head. They fry fuses constantly. They are evacuating markedly different sized spaces and I think they just push/pull each other into overheating. So since I put two batteries under the settee next to the mast, I thought let’s just start fresh and wire the pumps to the batteries that are close by and give them individual switches so they don’t trouble each other anymore. But then I realized that I can’t put the switch right there because they’re not ignition protected and wiring them in the same compartment where the batteries are is just bad kitty. Is there a way I could enclose the back side of the switch to protect it sufficiently from the battery space so as not to inadvertently blow myself up before sinking? Seal the back of the switch with a plastic box? Swallow a spider to catch a fly?
I hadn't thought about protecting against igniting hydrogen off gassing from batteries. I always thought ignition protection was for equipment in gas engine compartments. My switch isn't in the same compartment as the battery, but technically the battery compartment isn't isolated from non ignition protected equipment either.