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Author Topic: Bilge pump and float switch  (Read 1755 times)

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saltygirl

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Bilge pump and float switch
« on: April 17, 2017, 05:43:23 PM »

Need to replace our bilge pump and float switch again (replaced within the last year).  Pump runs so so with lots of back flow and switch died.  Recommendations?
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Celeste and Greg Ray

Jon W

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Re: Bilge pump and float switch
« Reply #1 on: April 17, 2017, 07:01:15 PM »

If only using one electric bilge pump Rule 1500 or 2000 with correct Rule float switch is a good choice.

I redesigned my bilge system to have a Rule 1500 with a float switch as primary and Rule 3700 and float switch as emergency backup. The discharge hoses were replaced with hoses with a smooth internal surface all check valves were removed and anti-siphon valves added. I put a write up in the Tech WIKI with photos if interested. Very little back flow when the pump shuts off.

Before doing any changes it would be helpful to understand your current system (including electrical) and pump brand/mfr.
« Last Edit: April 17, 2017, 07:06:32 PM by Jon W »
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Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

kwaltersmi

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Re: Bilge pump and float switch
« Reply #2 on: April 18, 2017, 06:13:05 AM »

My float switch failed, so I just replaced mine on Saturday with a 2000 automatic (internal float switch) wired to a 2-way fused switch on the panel. I did not use the manual hot wire, so I sealed it off.  I also replaced the discharge hose. Mine was routed from the transom (about 6" above waterline) over the top of the propane locker shelf (to get it well above the waterline to prevent backflow/siphoning), then down to the bottom of the bilge on the port side under the head compartment and finally to the middle bilge just aft of the mast.
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'87 C34 TR/WK M25XPB
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Ed Shankle

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Re: Bilge pump and float switch
« Reply #3 on: April 18, 2017, 06:25:14 AM »

Jon, I can't find your tech wiki write up. What category is it under? Or just send the link!
Thanks,
Ed
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Ed Shankle
Tail Wind #866 1989 m25xp
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Jon W

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Re: Bilge pump and float switch
« Reply #4 on: April 18, 2017, 07:10:35 AM »

It's under Leaks then Bilge in the Tech WIKI. It's hard to find but I didn't know where else to put it.
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Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

DaveBMusik

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Re: Bilge pump and float switch
« Reply #5 on: April 18, 2017, 10:51:29 AM »

I installed a Johnson "Ultima" switch last year. It is sealed and has worked flawlessly.
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Dave Burgess
Water Music
1986 C34 Hull #206, Fin Keel
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Paulus

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Re: Bilge pump and float switch
« Reply #6 on: April 19, 2017, 05:50:35 AM »

Jon,
What was the down side of the check valves?
Paul
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Jon W

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Re: Bilge pump and float switch
« Reply #7 on: April 19, 2017, 06:06:21 PM »

Check valves can get stuck open or closed. Neither is good.

If stuck closed the pump won't get the water out of the boat, if stuck open you could get water into the boat from outside (proper anti siphon loops can stop water from outside coming in).
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Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

DaveBMusik

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Re: Bilge pump and float switch
« Reply #8 on: April 19, 2017, 08:16:01 PM »

Check valves can get stuck open or closed. Neither is good.

If stuck closed the pump won't get the water out of the boat, if stuck open you could get water into the boat from outside (proper anti siphon loops can stop water from outside coming in).

They also typically reduce GPM flow
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Dave Burgess
Water Music
1986 C34 Hull #206, Fin Keel
Yanmar 3YM30
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J_Sail

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Re: Bilge pump and float switch
« Reply #9 on: April 19, 2017, 08:20:00 PM »

I'm told that anti-siphon valves can get fouled and stop working, too. Typical recommendation is to check them regularly (quarterly?). What's the fleet's experience?
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Noah

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Re: Bilge pump and float switch
« Reply #10 on: April 19, 2017, 08:48:03 PM »

Not sure what the concern is about the need for either a check valve or anti-syphon valve, vented loop is with the Mark I bilge pump plumbing, as the dischage is above the waterline. Perhaps in a big following sea or if you were way down below your designed lines, which may be the case if you are sinking, but then you would have the pump running with the head pressure would prevent any back-flow.  What am I missing?
« Last Edit: April 19, 2017, 08:48:28 PM by Noah »
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Jon W

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Re: Bilge pump and float switch
« Reply #11 on: April 19, 2017, 09:03:31 PM »

Run back of the water in the hose when the pump shuts off. Depending on how it is run the run back can be enough to cycle the pump more than needed otherwise.

The bilge should not have debris in it to clog the system.

Check valves and corrugated hose impact gpm/flow. I also changed to hose with smooth bore inside surface.
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Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca

Noah

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Re: Bilge pump and float switch
« Reply #12 on: April 19, 2017, 09:19:38 PM »

I do get a bit of "run back" due to length of uphill hose run, but nothing more than a couple of sponge squeezes. It would be interesting to quantify the difference between corrugated hose vs non-corrugated. Sounds like a perfect task for Practical Sailor. My gut feeling is, it's not significant enough to worry about, especially in a situation when it's "all hands to the buckets".
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1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

J_Sail

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Re: Bilge pump and float switch
« Reply #13 on: April 19, 2017, 10:26:55 PM »

On some boats the outlet for the bilge pump can be underwater if you'r heeling over hard. If it's underwater when the bilge pump turns on, when it turns back off you now have a siphon unless there's a anti-siphon valve to let air in to interrupt the siphon. The vent in the top of the loop is what the anti-siphon valve is (but it needs to be checked once in a while to make sure it's clear).

Perhaps all of this is not a problem on C34s? As some of you know, I'm only the electrical engineer brother of a C34 owner and mostly only know its electrical systems. My own personal sailing/maintenance experience is on other boats.

BTW, I agree that you don't want a one-way check valve. The slight improvement in run-back is not worth the reduction in flow.
« Last Edit: April 19, 2017, 11:41:30 PM by J_Sail »
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Jon W

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Re: Bilge pump and float switch
« Reply #14 on: April 19, 2017, 10:38:42 PM »

I recall Boat US estimated corrugated or ribbed hose caused a 20% reduction in flow.
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Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, 35# Mantus, Std Rig
San Diego, Ca
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