I have a 1250 GPH Johnson cartridge pump on Imzadi, similar to these: http://www.westmarine.com/buy/johnson-pump--automatic-submersible-bilge-pumps--P011006897 . Johnson also makes the West Marine pumps available in my local store.
All of these come with a check valve that is a small rubber cone similar to the joker valve in your head. It installs in the threaded “hose fitting” that is used to connect the hose to the pump, or it can be left out and an o-ring included with the pump can be used to seal the “hose fitting”. The float switch turns on when the water is 2” deep, and turns off at ¾”- the downside being that there is normally a bit of water in the bottom of the bilge. My biggest reason for buying this particular pump was the removable pump cartridge motor. You simply lift the plastic retainer ion the outside of the pump body and take the motor and impeller out. Makes cleaning gunk out of the pump (and replacing the motor) really easy. And changing the pump in the small bilge area of my 38 can be a real b*_^#h. The switch comes attached to the base of the pump, but can be removed and located separately. That is what I had to do because of the limited area in my bilge. Upside is the switch is a shade lower than the pump, so the standing water in the bilge is more like 3/8” to ½”. >From the initial installation in 2009-2010 until I replaced the pump motor >last summer, I had ignored the conventional wisdom and had the check valve >installed. Never had a problem except the occasional need to clean the dog >hair and other gunk that migrates into the bilge over time. (Which problem was >identified when the pump ran longer than 10 or 15 seconds to clear out the >bilge.) But conventional wisdom must have some basis – so last summer I took the check valve out. Like Dennis’s, my pump spurts for a few seconds and stops. But then the water in 10 or 15 feet of ¾” hose starts to drain back into the bilge. After a couple of minutes, the pump spurts and stops. Repeat cycle. The bilge is normally pretty dry, so my temporary solution this fall was to just turn the pump off and about once every week or two to turn the switch to automatic, let the pump do its thing for one cycle, and live with the water in the bilge. This conversation has reminded me that it is time, while I’m doing other projects on the boat this winter, to put the check valve back into the hose. Oh, and BTW, a diaphragm pump by definition has a flapper (check) valve on the outlet side of the pump plus one in the inlet. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Dennis C. via CnC-List Sent: Saturday, January 02, 2016 7:28 PM To: CnClist <cnc-list@cnc-list.com> Cc: Dennis C. <capt...@gmail.com> Subject: Re: Stus-List Automatic bilge pump switch help Despite the "conventional wisdom" against check valves in bilge discharges, I've had one in Touche' for a decade and a half with no issues whatsoever.
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