JSO 42DS Float Switch/Bilge Pumps Wiring Help

Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
The existing set up (which I'm trying to change) is as follows: There are two bilge pumps, one is a diaphragm pump mounted high near the fresh water pump without a float switch and operates continuously only when the three-way panel switch is on ON. There is another bilge pump with internal float which is plumbed to the manual cockpit pump intake hose and I guess it pushes the water out through the rule cockpit pump!! It operates when the panel three-way switch is on AUTO when it's float switch is activated. When on auto, the other diaphragm pump obviously is disabled and without power. Very difficult to trace where the wiring splice was done to accomplish this.
I want to add a float switch to the diaphragm pump so it can be left on and operate automatically. How do I wire the float switch to the pump since it gets no power when the switch is on AUTO? I could run a new wire from the auto bilge pump to the diaphragm pump but not sure how to retain the integrity of the system. What I cannot do, is run a new wire from the panel to the bilge due to the panel location. I opened up the panel but the three-way switch is connected to a printed board that I do not want to mess with. Any electrical geniuses out there? Thanks.
Lee

Read more: http://jeanneau.proboards.com/thread/6897/float-switch-bilge-pumps-wiring#ixzz5ViQQQBQS
 
Apr 22, 2011
865
Hunter 27 Pecan Grove, Oriental, NC
If you add a float switch to the diaphragm pump and still want to retain the ability to activate the pump manually, you have to have two hot wires. One to the float switch and one that bypasses the float switch and connects directly to the pump. I would recommend connecting the wire to the float switch directly to the battery instead of using the bilge switch,, with a fuse near the battery of course.
 
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Likes: Lee Hadjiosif
Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
I want to thank everyone who took the time to contribute to my quest. After taking everyone's suggestions into consideration, tracing existing wires, taking meter readings etc and identifying the wires I decided how I should proceed!!!
-I will wire BOTH pumps to the hot wire from the AUTO side of the three-way switch after I add a float switch at the bottom of the bilge wired in series to the diaphragm pump which doesn't have one now. So both pumps will be hot when on AUTO. They should not work at the same time since their float switches are about 30cm apart in height (except in a very serious flood). Both pumps total 11Amps and the existing fuse is 12amps so I will use 1.29mm/16gauge wire for all the additions.
-I will wire the ON side of the three-way switch to the diaphragm pump which will have the float switch at the very bottom, in case I want to drain every little drop of water.
I wish there was an easy way to install two separate three-way switches to the panel, but the work involved in doing so makes the project ridiculously hard. I hope this works for me.
Thanks, Lee H.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Careful with the wire capacity. (Remember, you need the neutral wire to be sized, just as the "hot".)

If those two pumps need to run continuously they may exceed the load.

Often the bilge pump bypass the breaker panel and go directly from the battery.

I think the safer approach is to provide two separate hot and neutral wires.
 
Oct 29, 2016
1,915
Hunter 41 DS Port Huron
@Lee Hadjiosif SG has a point in reference to wire size/capacity, look at your pumps amp ratings combined and then the gauge of the wire feeding them as well as the approximate length (ie 20 A @ 15 ft = 10 ga) to ensure that the circuit/wire has the capacity to carry that much current with a reasonable safety margin.
I would guess that the wire from the switch to the pumps is adequate but the wire from the fuse to the switch may need to be increased as well as the fuse itself, I would also assume that the grounds are adequate as the pumps sound like they are in different locations.
I am surprised that the high level diaphragm pump is strictly a manual operation, ergo the fact you would have to be on the boat should a flooding situation arise, no pun intended.
Wire gauge chart
http://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg
 
Last edited:
May 17, 2004
5,025
Beneteau Oceanis 37 Havre de Grace
I agree with the others on the wire capacity. In addition to wanting a safety margin, you don't want to introduce a voltage drop that will reduce pump capacity. Using 16 gauge will give you about 1V drop every 10 feet of wire at 12 amps.

The other concern that I have with your plan is that a short in one pump will trip the breaker and disable them both. I understand that might be the easiest way to run the wires, but it would be more robust to separately fuse each pump.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Does your Beneteaux have a distinct breaker for the bilge pumps?
 
Apr 22, 2011
865
Hunter 27 Pecan Grove, Oriental, NC
Your idea should work Lee as long as the wiring and fuse is adequate for a extra load. You will still have two independent pumps even if the primary pump or it's wiring fails, as the second pump could be operated manually in the three-way switch ON position which is what your present system provides.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Does your Beneteaux have a distinct breaker for the bilge pumps?
Yes it has a 12amp fuse.

That's not a breaker, Lee. That's simply to protect against a short in the pump or wiring to it from causing a fire or draining down you battery (or whatever).

I believe (though I'm not sure) that your bilge pump is wired directly to the battery or the battery switch. I don't believe you have a breaker on your panel. As such, your only fuse is that 12Amp fuse. If you put another bilge pump in, and both are going, I think that EACH needs to separately wired and fused. Each needs its own sized neutral wire, too. I don't see any reason not put the higher bilge pump on it's own float switch. If you need to turn it on, I suspect you'll be distracted.
 
Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
The Jeanneau bilge pumps are not wired directly to the battery!! The Jeanneau fuses have a unique feature where there's a little button on the back of the fuse that trips down in the event of overload.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
The Jeanneau bilge pumps are not wired directly to the battery!! The Jeanneau fuses have a unique feature where there's a little button on the back of the fuse that trips down in the event of overload.
I would strongly urge you to consider a few things.

Wiring your bilge pumps independently each with their own AUTO-OFF-MANUAL switch

Giving each pump the fuse the manufacturer calls for and no larger. Bilge pumps are one of the few items where the fuse size should not exceed that of what the pump manufacturer dictates. (see #2)

Get rid of the internal switch pump. It will fail, and when they do they often fail stuck on.

A good basic bilge pump design looks like this..

Emergency Pump = Largest Rule or other centrifugal pump you can physically fit. Pair it with an Ultra Safety Systems Junior or Senior float switch and set both pump and switch at a higher level that keeps them out of routine bilge water. This cuts down on DC corrosion risk tremendously!!. (IMPORTANT: DO NOT USE CHECK VALVES ON CENTRIFUGAL PUMPS)

Nuisance Water Pump = Diaphragm pump (check valves are okay on diaphragm pumps) and an Ultra Safety Systems Junior or Senior float switch set for lowest desired water level. Note: All wiring for electric pumps shall be sized for no more than a 3% voltage drop.

Manual Pump = Henderson/Whale etc. with no check valve just a strainer.



Bilge pump problems are generally related to a number of different issues:

#1 Poor bilge switch chosen for the task - Ever since the removal of mercury from the Rule etc. float switches the reliability has been about as good as a Yugo and they tend to last about as long as a bag of Doritos at a Grateful Dead concert.. How to Rx? Don't buy unreliable products. The switches from Ultra Safety Systems are about as reliable as they get.

#2 Inadequate bilge pump system design - A good bilge pump system makes use of a "nuisance pump" which is a diaphragm style and a second emergency pump or oh $hit pump which is a high capacity centrifugal type. The nuisance pump does all the routine work and the oh $hit pump is used only in emergency situations and the switch is mounted slightly higher in the bilge. As always a manual "gusher" style pump should be installed with a cockpit handle..

#3 Improper system design and install - Centrifugal Rule type pumps should not have check valves installed in the outlet hose. Check valves are a band-aid at best and owners and even builders often choose them over a proper installation but should not. They are flat out dangerous at best, and battery killers at the very least. It's one of the number one causes of destroyed battery banks other than cheap bilge switches I see. Centrifugal pumps should also use smooth walled hose, utilize a siphon break and have as few bends as possible. The discharge should always be above max heeled waterline, in a well designed system.

#4 Wire should be sized for the least voltage drop to maximize performance. Centrifugal pumps will never pump anywhere close to their rating "as installed" so the biggest capacity oh $hit pump you can fit is the best choice.


Best bet to avoid these issues:

Install a well designed bilge pumping system utilizing a nuisance pump (diaphragm type). Use quality bilge switches such as those by Ultra Safety Systems, use sufficient wire for minimal voltage drop, use water proof splices for all wiring terminations, make all terminations above bilge height when ever possible, fuse the pumps per manufacturers recommendations and do not use a check valve on any centrifugal type pump. Check valves are fine on a diaphragm pump but a very bad idea on a centrifugal bilge pump...

Sadly the best bilge switch ever made was discontinued because boaters refused to pay for the technology and reliability. I bought an extra before they ran out....;);) That said I have yet to have or see an Ultra Safety Systems bilge switch fail....

Misleading Marketing:

Bilge pumps are some of the most grossly misrepresented items we use on boats today and many of us in the industry believe this is borderline criminal.

We have three major items that inhibit the performance of your pump.

Friction Head Loss
Static Head Loss
Voltage


These pumps are rated at what is commonly called the "open bucket rate" or ZERO HEAD and they are rated at charging voltages of 13.6V.
Fair? Hardly...

In a University of Virginia study, they found most pumps delivered 15-33% less than what the manufacturer claimed even when tested as they rate them at "open bucket"..

One 2000GPH pump that was tested claimed 2000GPH at zero head. Testers found it delivered just 1500GPH and zero head. This is 500 GPH below what the pump maker lied to the consumer about on the box and we've not even installed it yet to realize head losses. They also claimed the pump to be capable of up to 18' of head, and it could only muster 14' of head... If voltage drops below 12V the performance gets even worse. That 2000 GPH pump at 10V could only produce approx 420GPH at 7' of head. Seven feet of head is fairly common on a sailboat. Bump that to 12V and we get approx 720GPH. Course this is just static head and does not include for friction head (fittings etc.) and voltage..

Lets look at some actual test data for a 600GPH pump.

600GPH Manufacturer Label (assuming it actually performs at that rating)
Running Pump at 12V = Loss of 141 GPH
3' Static Head = Loss of 179 GPH (3' is NOTHING on a sailboat)
10' of 3/4" Corrugated Hose = Loss of 114 GPH
1 3/4" Thru-Hull Fitting = Loss of 11 GPH

In a typical installation a 600 GPH pump (on a power boat with only 3' of static head) will only deliver 155 GPH "as installed". Now add a check valve, and a sailboats static head, and you are well below 100 GPH for a typical sailboat running a 600GPH pump.

I would urge all boaters:

Do not share hoses
Do not share thru-hull fittings
Do not use check valves on centrifugal pumps
Do not use corrugated hose
Do not allow any dips/water traps in outlet hose
Do not fuse the pump at beyond the manufacturers suggested size
Do not use any 90 Degree fittings

Do use smooth walled hose
Do buy the biggest pump you can fit
Do use quality bilge switches
Do use waterproof splices
Do keep all terminations out of bilge water
Do use wire that results in the least voltage drop
Do use a dual or tri-pump configuration
Do install a high water alarm
Do use a siphon break