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Thread: Bilge pumps

  1. #1
    Member Akgramps's Avatar
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    Default Bilge pumps

    I am in the process of wiring a 24' GlasPly, all new wiring, so clean slate.

    I plan to reuse a rather large Rule 3700GPH pump, its a bit large and will be the secondary pump.
    I have checked the draw on the pump and it draws 11+ amps, Rule claims 15.5A.

    If I switch this pump at the helm it will theoretically require a #8 wire just for the pump using the 3% voltage drop rule or a #12/14 using the 10% voltage drop.

    It is about 18' run of wire one way and there will be other items on that panel such as small refer (4A), D-2 Espar (3A), fresh water pump (1.6A), some LED lights (2A) and 2-12 volt outlets. Its doubtful all these items would all be on at once but certainly possible for the heater, refer and lights. So maybe a 8 amp load, add the bilge pump and its right at 20 amps. This requires a #6 wire for 3% drop and #10 for a 10% drop.......

    Does this seem right to you guys? I could use a relay, however it just adds more components and I think a bilge pump should be wired as simply as possible....

    I am tempted to just run a #10 boat cable for this panel, or I could get a smaller pump..... 3700 GPH is a big pump, but a lot of water in a small boat is much worse than water in a big boat, also this is a sterndrive so big hole in the transom sealed with a condom. And sterndrives engines are low and water levels can be a issue quick (not self bailing). That said I would like to use this pump.....
    “Nothing worth doing is easy”
    TR

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    Member Bullelkklr's Avatar
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    The bilge pumps in my boat have a switch local on them with three wires coming out. One is for control of the switch, the others are neg and pos to the battery.

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    I think of a Bilge pump as a emergency devise and there for it should be on its own circuit. Also it should have a light and buzzer to tell you when it on. I also suggest you wire the pump so it can be unplugged so if it go bad you will not spent hours rewiring a new one.

    When Rule said it draws 15.5A I think that when the pump is under load?

    I use inrush current when calculating wire size at 3% wire loss and don't forget a circuit breaker.

  4. #4
    Member Akgramps's Avatar
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    Quote Originally Posted by Bullelkklr View Post
    The bilge pumps in my boat have a switch local on them with three wires coming out. One is for control of the switch, the others are neg and pos to the battery.
    Bull, do you recall what size/ brand pump? It must have a built in relay.

    Quote Originally Posted by MacGyver View Post
    I think of a Bilge pump as a emergency devise and there for it should be on its own circuit. Also it should have a light and buzzer to tell you when it on. I also suggest you wire the pump so it can be unplugged so if it go bad you will not spent hours rewiring a new one.

    When Rule said it draws 15.5A I think that when the pump is under load?

    I use inrush current when calculating wire size at 3% wire loss and don't forget a circuit breaker.
    15.5AMPS is under load, I checked my pump with a clamp style CT and it was 11.2A.
    It will be on a separate breaker, and this pump will be a emergency secondary pump. If this pump is on I am either testing in or bad **** is happening. It will be strictly on manual. I will know when its running....

    A light will just tell me the circuit is energized, the pump could fail or be jammed with debris and the light and buzzer would be on, seems like that is just more unnecessary wiring. I will have a primary pump on a different panel/circuit that will be ~1000 GPH. This one will be the primary pump. Also on manual at the helm. I may decide to use some type of auto switch for that one, however it will be wired directly off the battery, no point in running that wiring to the helm either, however in that case a buzzer is a good idea as it could come on at night and I may not hear or notice it running. Its hard to imagine something springing a leak while hanging on the hook....! There are no thru hulls....except the outdrive...
    .
    The big question is what size wire for the pump? Or use a relay?
    “Nothing worth doing is easy”
    TR

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    Member DRIFTER_016's Avatar
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    I have a bilge pump control panel on my boat.
    I have dual pumps and dual float switches, one mounted a couple of inches higher than the first.
    When there is water in the bilge pump one will come on automatically. If there is a malfunction of the first pump, the second pump will come on when the water level reaches the second switch.
    The control panel has a 3 position toggle switch, indicator light and an alarm.
    The 3 positions of the switch are Automatic (uses the float switches) Off (turns all power off) Manual (turns on both pumps @ the same time.
    The second level switch is also used to trigger the alarm.
    This will let me know there is an issue with pump one (or something serious in the bottom of the boat) and the second level switch has engaged.



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    wire pumps direct to batteries with a on/off/auto float switch on each pump, no relays or anything else to screw up. If your looking for pump Johnson pumps and float switches seem to hold up well. High water alarms are also nice to have as well as a high temp/no water alarm on the exhaust hose right after it comes off the exhaust elbow.

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    Member Akgramps's Avatar
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    Ok, you guys got me thinking now, this is trailerable boat so I was thinking simple.... however the auto switch is making more sense.
    Its not self bailing so if washing down it may prevent running back and forth to turn on the bilge pump at the helm.
    “Nothing worth doing is easy”
    TR

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    Member Bullelkklr's Avatar
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    I don't remember the models of my bilges. I have to put the batteries in here in not too long so I'll take a look.

    I have both wired up directly to the batteries. They are both on float switches. One is also on a switch at the helm for manual control to turn on in case I want to check. One is about 2" higher than the other (float level).

    IMO one needs to be hot and on a float level switch when it is anchored and I am not in the boat. If it rains a lot it will pump out. They both will run when my OFF/1/2/ALL battery switch is "OFF" (only thing that will except main motor which is wired direct also).

  9. #9

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    Akgramps,

    Food for thought: http://store.waterpumpsupply.com/ru12vodcaubi.html

    I had a bilge pump like this on our Tolman skiff that I liked and worked fine for my applications; a non self bailing boat, in a slip in Seward for the summer.

    Here are the details of how the bilge pump operates: Rule Pumps 12 Volt DC Automatic Bilge Pumps 500 GPH - 2000 GPH feature computerized operation on the principle of impeller resistance. Float switches are not required. The pump will turn on every 2-1/2 minutes to sense for water. If water is present, the pump will sense resistance and continue to run until all the water is removed. Thereafter, it will check for water every 2-1/2 minutes.Power use in the checking mode is minimal.

    It worked as advertised and I had no problems with it for the 6 years I owned the boat. I believe the model we had was a Rule Platinum 1000.

    Doug

  10. #10
    Member DRIFTER_016's Avatar
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    Quote Originally Posted by Akgramps View Post
    Ok, you guys got me thinking now, this is trailerable boat so I was thinking simple.... however the auto switch is making more sense.
    Its not self bailing so if washing down it may prevent running back and forth to turn on the bilge pump at the helm.
    My boat is trailerable too.



    This is the one on my boat: http://osculati.com/en/cat/Scheda.aspx?id=1254

    This seems to be the updated version of the same thing: http://www.go2marine.com/product/442...mp-switch.html

    Here is a picture of mine in the console before installation.
    It is the unit directly above the radio on the left side.


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