JSO 42DS Float Switch/Bilge Pumps Wiring Help

[leehadjiosif]

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

[vasko]

Can yiu elaborate a little more ? How the auto bilge pump inlet is connected to the manual bilge inlet ? sounds impossible ....


in general my guess is that your system is setup this way for the self-priming pump to be used manually to clear the water left in the bilge afte the auto pump has finished..

[leehadjiosif]

The two pumps do not share any part of the plumbing. The auto pump is sitting in the high bilge while the manual pump is drawing from the bottom of the deep bilge with two independent hose outlets. The deep bilge must overflow before any water gets to the auto pump's float switch which is not acceptable to me. I want a float switch in the bottom controlling the manual pump. The question is how to change the wiring so both pumps can get power while the switch is on auto. Obviously there must be two red wires connected to the switch but not as simple to see and change since there is a printed circuit board behind the switch.

[rc sail]

You should/may have an additional DC fuse panel that you could hook into to get DC power to your high/aux pump.The power would be continuous to the float switch but protected by the fuse.

[rc sail]

leehadjiosif-reading your post further there should be 2 red/positive wires coming from the bildge switch at your
electrical panel. Your lower/deep bildge pump should have 3 wires from the pump, 2 positve and 1 black for ground.
One positive goes thru float switch and the auto side of the bildge panel switch. The other positive would connect
to the on side/wire of the switch, which is currently appearing conected to your diaphram pump. Seems a prior owner
relocated the auto switch side wire from your diaphram pump to the later installed lower bildge pump. Hope this helps.

[alenka]

First thoughts would be to run a new circuit via a second switch (and fuse) so that you have full control over both pumps.

On my 43 DS there is just one pump, with float switch, but this can be overridden and turned on by the three way. Which means if the float switch fails you can still turn on and off the pump manually. To me that is the best of both worlds.

Sorry, not going to be aboard until next year but will gladly make a note of the wiring if you can wait that long.

[rene460]

Not really so mysterious.  Certainly the two pumps can operate in series on the water side, though I would recommend a strainer in the inlet line at the bilge, otherwise the first pump will be the strainer for the second.

If both are diaphragm type, not even reduced capacity, but probably higher current draw, but it makes sense to use the same water outlet through the hull.

I assume the bilge pump wiring is similar to mine, sometimes a faulty assumption, but your description of the switch wiring is the same as mine.  You don't need to go back to the panel.

Start at the pump end.  The float switched pump has three wires, the negative obviously, a red live for continuous on, and a white, which is also live but for auto operation through the integral float switch. (Colours may vary on your model, particularly the White). So start at the pump and follow the wire back to find where the second pump is joined in, and a convenient point to join in a new float switch for the second pump.  Should be a joiner in the loom not too far along the wire.

The arrangement seems to involve a second pump added by a previous owner, (not an unreasonable thing to do) so it is not easy to guess where it might be joined in.  You will need a separate float switch down in the bilge for what you want to do.  Wire through the float switch from the White wire, and the live for continuous on is obviously already there.  You may need a larger fuse/breaker to operate the second pump at the same time as the original, and that fuse is a common point of failure for both systems, that is, if the fuse blows, neither will work.  It may be worth running new wires to the second pump either from the main 12 V electrical distribution terminal, or from a second emergency bus which you install to remain live when your normal main breakers are in the off position.

rene460

[vasko]

Thinking further - you may be kind of a stuck - e.g in all scenarios will not easy:

1. Scenario -1 - if you use the same power source for both pumps - then most likley the pumps are connected like they are currently because the fuse / cables cannot supply current for both pumps in tbe same time.

2 Scenario -2 - run a completely new power source for the manual with saparate switch, fuse and floating switch. All will be good but alot more new cableas and work etc.

[leehadjiosif]

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.

[vasko]

just be careful with the fuses and current calculation e.g. usually when a pump is rated 3.5amps the fuse is 5amps  e.g. the fuse size usual is about 30% more then the rated current  - also when you put both together on one fuse there are more complications :  e.g.

case 1 - fuse = fuse (1) + fuse (2)  - then when only one is working  the fuse it too big and will not cut the power on time

case 2 - fuse = fuse(1) - then when both start working the fuse will blow.

[rene460]

It is always an interesting conundrum, fuse ratings on emergency equipment. Like a low oil pressure on a refinery fire pump, do you want to always protect the pump engine, or is it better to hope that it lasts until the fire is out?

Also the fuse ratings must allow for a bit of a surge current on starting, which can be quite high on something like a bilge pump which could have a bit of salt or corrosion making it more difficult to start.

I would definitely not recommend a common fuse for both pumps. If it blows, neither will run. So try and join in on the battery side of the existing fuse, and install a separate fuse for the second pump.  And use a generous wire size, you do not want any excess voltage drop in the cables when you are trying to save the boat.

If that is proving impractical, you could think about replacing the existing fuse with a big one, rated only to protect the cable, (let it get hot but not melt the insulation) then, where you split the supply, instal a junction box with separate fuses, and even separate on/off switches for each pump. This could be located above seat level, hidden behind the back cushion, so above a moderate flood. It certainly makes sense to have a reasonable protection fuse on the one with the low float switch which you might expect to use more often for minor amounts of water from the hot water service or fridge or replacing the log transducer or plug. And no use burning it out for the most common situations. Perhaps a bit higher rated fuse for the one with the high float switch, which you might call the emergency pump. It just takes a bit of thinking and drawing a schematic to do what you want.   And do insert a markup in the wiring diagram of you document folder to show what you have done, it is the sort of thing we all forget so soon!

If you really want to go the whole way, you could take both the always on and the auto on wire into your junction box and install three way on/off/auto switches in your junction box. And it is not too silly to consider a separate power supply wire from the battery, red and black to the emergency pump, so it will work even when your main isolator switches are off.   But sometimes, trying to cover all contingencies becomes too much.

Rene460

[leehadjiosif]

Rene,
I wish you could have given this thesis to the panel manufacturer (scheiber} before they designed their panel. I have no intention on redesigning the panel to add more safety to it. 
Lee

[vasko]

Lee - just be careful what you do

[rene460]

Hi Lee, please don't take my post as any criticism of the panel, mine has worked without fault for nine years now.  Even the odd occasion when the reverse polarity light has shown any life, it was traced to a definite fault (actually in our power cord. The standard 15 amp extension leads do not stand up to even reasonable care around the boat, perhaps I coil them a bit tight when putting them in the locker to go sailing.) Having a smaller boat, my panel is probably the more basic version, and just has three LEDs and a three way switch to indicate the battery voltage on both the engine battery and house battery instead of a voltage display. Jeanneau have wired it with a separate (fused) wire from the battery, so it is minimally affected by other loads, otherwise similar to most. I am sure the basic offering is fit for purpose for the vast majority of owners.

I would also not advocate modifying the panel. It is not for the hobbyist, including me, and those who do have the appropriate know how and experience will know what they can or can't do. The circuit diagrams are worth studying to understand what goes on in the panel only. And any safety features have to be separate from the panel to avoid common points of failure.

I am sure that your boat did not come with the two pumps, the second has been added later. If it is wired through the Schreiber panel, the current drawn by both pumps operating at the same time could well exceed the intended switch or board rating, (I don't know the rating) hence my suggestion of considering a separate supply from the battery. I believe both the additional pump, and a separate "emergency supply" system are commonly part of the preparation for any serious ocean cruising. Then make sure your wire sizing is large enough to minimise voltage drop over the distance required.

The question of whether to leave the main in the breakers on or off position when you leave the boat is a perennial one, and the bilge pump is the main issue. When we bought our boat, the agent advised to always close the through hull valves, switch off at the main breakers, and remove the shore power cable. So this has been our procedure. Our marina rules also require removing the shore power cable when away from the boat, so our solar panel keeps the batteries topped up when we are away.

In the days when most boats were built from wood, leakage was always a problem, or at least a problem in waiting. You would not want to isolate the bilge pump with such a boat. With a fibreglass hull, you can generally keep it dry. The only real point of likely water entry in significant amounts is the shaft seal, and even these will only drip a bit if they are worn, so long as they are not gushing when the engine is turned off. But these days, as far as I can see, production boats commonly come with a basic system which works for most but can be improved by those who see the need.

I have seen separate emergency panels on other boats. The idea seems to be that you do not want some electrical fault to cut supply to bilge pumps in particular, maybe vhf or hf radio or the small number of things you really might need to operate in an emergency. Ideally there should be completely separate wires from the battery, run in a different way around the hull, so a single fault cannot normally affect both. Even the batteries for it require thought, perhaps using a bow thruster battery if you have one, for example. But somewhere along the line we have to work out what is practical and sensible. I think a simple junction box behind the seat back rests is a possibility for something a little below the ideal, but perhaps more practical and quite adequate for your situation.

I probably go overboard (oops! Not a good word choice in this situation) in considering these issues, but that comes from a work history which involved safety reviews among other things in petroleum refineries and similar plants. So it is ingrained in me to think that way, but I also have to try and seek a practical balance.

Sorry for another "thesis", some of these questions have so much more to them than first appears. The main aim is to increase understanding of how our boat systems work, starting with the information we have available.

Rene460