I installed an automatic bilge pump switch ..but there is a problem..when the water is high enough to trigger the switch( the switch is on the same level as the pump,in the same bilge section) the backflow from the hose flows back into the bilge,triggering the switch again which pumps it,stops,the backflow returns,triggers the switch again ,over and over again..its just pumping the same backflow water over and over again...what are you guys doing differently? what did i do wrong?
—
"Sailing Still" 1990 C36 M25 wing
Sail Canada/Transport Canada training
Gibsons Harbour BC
www.landsendbc.ca
I bought a back flow preventer valve at West Marine, route up hose of pump, going out the original discharge line. Some of the "purists" might say nay, nay, nay,but works for me. Twice during season might want to make sure nothing caught in flapper valve (little bits fiberglass construction stuff that might have made it's way into bilge).
peter g
2000 C36, MK2, Hull. #1897
wonderful, wonderful, wonderful ! ! !. 5 th Catalina
I use a check valve also and it works well.
2000 C36 MKII 1825
Guys ,where does the check valve go?Right next to the pump? Does it not seep back?
"Sailing Still" 1990 C36 M25 wing
Sail Canada/Transport Canada training
Gibsons Harbour BC
www.landsendbc.ca
Greig,
Nobody has ever accused me of being a purist, but I have read in many sources that a check valve does not belong in a bilge pump hose. Yes, they can work, but........ The check valve that was in my boat when I bought it (factory? PO?) would often keep the water flow from starting, even though the pump was working properly. Not good. After a lot of research, I decided remove the check valve and install a second, smaller bilge pump, specifically to avoid the backflow problem. This solution might be a bit more work, but the results have been outstanding, both in my C36 and recently in my C400. Hope this helps.
https://www.catalina36.org/members/technical/upgrades/adding-second-bilg...
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
Thanks guys,will give the smaller pump method a try.
"Sailing Still" 1990 C36 M25 wing
Sail Canada/Transport Canada training
Gibsons Harbour BC
www.landsendbc.ca
I think it's very important to not have a check valve in your main bilge pump hose. It can block.
If you have two pumps as Tom Soko recommends, the smaller one of them can safely have a check valve.
Every hose that terminates in a through-hull that might be under water must have an anti-siphon valve. Mostly the bilge pump hose on our boats doesn't have that because you assume the transom won't be under water for long. But it will be under water in a following sea. It should have an anti-siphon valve.
The second smaller bilge pump you install can have an anti-siphon valve mounted up under the galley counter beside the underneath of the sink. Besides preventing a siphon this will reduce even further the amount of water running back into your bilge.
If you want to you could put a check valve just up from the pump as well, which would mean you would consistently have water in the hose from the check valve to the anti-siphon valve. I don't have a check valve in my secondary bilge pump hose, but I do have one in the shower sump bilge pump hose.
Besides all this you should take care with mounting the pumps and float switches. The float switch has a range ... it will turn on at a certain level and then pump until it reaches a lower level at which it shuts off. The upper level is the one that must be kept above the level of the water that runs back in after the pump shuts off.
hope this helps,
Nick
Nick Tonkin
*Former* Website Administrator, C36/375IA
*Former* owner, C36 tr/fk #255, Santa Barbara, CA
I would think a spacer under the bilge pump would solve the cycling problem with the backwash. Your bilge would not be completely dry.
Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine
Spacer under the float switch, maybe?
Nick Tonkin
*Former* Website Administrator, C36/375IA
*Former* owner, C36 tr/fk #255, Santa Barbara, CA
Yup, that would be right under the float switch!
Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine
Gary,
Since you are a Content Editor, you can not only edit your post (as all users can) but you can delete posts too. If you delete your first post all the replies will be deleted, too, including this one, and you can post again. Or delete my first response and then edit your post.
Just pointing out some of the functions you can do.
- nick
Nick Tonkin
*Former* Website Administrator, C36/375IA
*Former* owner, C36 tr/fk #255, Santa Barbara, CA
Nick,
Sometimes you just have to "own" up to your mistakes, but I will keep that in mind as I did forget that I could cover up my errors.
Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine
Any reason why i cant plumb the new small pump with siphon break into the sink drain with a tee right above the thru hull?? Seems so handy,convenient and tempting....
"Sailing Still" 1990 C36 M25 wing
Sail Canada/Transport Canada training
Gibsons Harbour BC
www.landsendbc.ca
[quote=greigwill]Any reason why i cant plumb the new small pump with siphon break into the sink drain with a tee right above the thru hull?? Seems so handy,convenient and tempting....[/quote]
I'd say the #1 reason why you might not want to do this is that you would have to leave the seacock open all the time in order for the bilge pump to be able to do its thing. Not to reopen a discussion that's been had here (and elsewhere) a number of times, but it seems that most owners (although by no means all) believe its a better practice to close all seacocks when the boat is left unattended, since all it takes is a rubber hose rupturing or the hose clamps failing to sink an unattended boat. If you want to close the galley seacock, obviously you'd need to switch off the automatic bilge pump, which defeats the purpose.
However, if you don't care about being able to closing off the seacock, the #2 reason could be (and this is, I confess, mostly rank speculation on my part) that it might not drain as well since the pump would need to overcome the static pressure of the standing water in the drain (ever notice how slow the sink can drain at times? Is there a chance some of the yucky bilge water will back up into the sink?). Since you want to empty the bilge quickly if necessary, routing it to a through-hull that's above the waterline seems more sensible (although the longer hose does create some friction losses as well).
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Check valves do not belong of centrifugal pumps. Rule will flat out tell you this. A well designed bilge pumping system, on a 30+ foot boat, would consist of:
1 High Capacity Centrifugal "Oh $hit" pump (Rule 2000 or bigger)
1 Diaphragm Bilge Pump
The diaphragm pump is virtually unaffected by head loss, unlike the centrifugal pump, has natural check valve properties and CAN handle a check valve in the discharge or pick up line. This pump takes care of nuisance water and the centrifugal takes care of oh $hit events..
Problem is that most boat owners don't want to pay for a well designed bilge pumping system and most builders refuse to spend the money on a solid design. If you do it right there will be no issues. If you insist on a check valve on a centrifugal pump, make sure your insurance is paid.....
"The Rule Pumps FAQs.
Can I install a check valve on the pump discharge?
Check valves are not recommended
Why doesn't Rule Pumps want check valve on the pump's discharge?
Check valves are prohibited by the American Boat & Yacht Council for use as an anti-siphon device-and with good reason: They're notorious for failing in both the open and the closed position, which respectively leads to flooding or failure to pump. If the valve is close to the pump, the pump may not be able to overcome the weight of the water on the other side of the valve, rendering the pump ineffective
Why does my automatic Rule Pumps turns off if I install a check valve on the discharge of the pump?
The automatic bilge pump turns on about every two and a half minutes to "check" for high water. If water causes resistance on the pump, it continues to pump until the resistance lowers. With the check valve installed at the pump, it cant feel the weight of the water, and shuts off, allowing the bilge to fill with water!"
-Maine Sail
https://www.marinehowto.com/