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Author Topic:   Auto Bilge Pump Using Two Way Switch
Mark D posted 06-01-2011 07:29 PM ET (US)   Profile for Mark D   Send Email to Mark D  
I am adding an auto bilge pump switch to my existing bilge pump. Right now without an auto switch it only comes on when I pull the two-way switch out to turn it on. Has anyone ever used a two way switch for an auto bilge pump set up? I want to be able to leave boat on mooring and have a the auto switch do its thing while I am away and also be able to operate it manually. Has anyone wired one like this before? Can anyone comment on this?
jimh posted 06-01-2011 09:06 PM ET (US)     Profile for jimh  Send Email to jimh     
The notation of a "two-way switch" seems to me to imply that such a switch has only two states. The request is for a circuit to control a device in three states. I do not believe it is possible to create three states of control with a control device that only has two states.

The two states of the "two-way switch" would be ON and OFF.

The three states of the device (the pump) would be OFF, ON, and AUTOMATICALLY ON WHEN NEEDED

If the device to be controlled incorporates some special logic which can interpret sequences of control signals, you could send signals to the device by operating the two-state switch in a certain pattern. For example, if the device contained some intelligence and could read patterns of control signals, you could use the two-state control device to send a signal to the device to assume a certain mode.

I used to have some outdoor lighting which had intelligence in the controller. If you turned the switch that controlled the device from OFF to ON, then back to OFF in a certain period of time (which I think was about one second) the device would interpret this as a signal to go into a different mode.

Of course, such signaling depends entirely on the device having the intelligence to interpret the signals, and the operator being able to fashion the signals. So as far as a simple device like a pump, there is no control possible, but, if the pump has some intelligence incorporated into its design, you could control it in several different states using only a two-state control.

If a device has intelligence and can be controlled as I have described, you just need to read the instructions that came with it to learn how to control it.

jimh posted 06-01-2011 09:25 PM ET (US)     Profile for jimh  Send Email to jimh     
It is often seen that a pump intended to provide automatic operation will have three electrical leads. There is no circuit that I can imagine in which one could connect three leads to a control device that only has two leads which would lead to being able to provide three states of control.
Mark D posted 06-01-2011 09:46 PM ET (US)     Profile for Mark D  Send Email to Mark D     
What [if] I tapped the hot wire coming into two-way switch and attach the third wire from auto float switch there, before the switch?
jimh posted 06-01-2011 10:11 PM ET (US)     Profile for jimh  Send Email to jimh     
I think you are introducing an entirely new device into the circuit, the "auto float switch," which was never mentioned before. With more devices, more connections are possible.

It is almost impossible to describe wiring by using a narrative form. The wiring of circuits is generally described by use of schematic diagrams. If you can read a schematic diagram you can find several wiring arrangements shown in an article I authored on the subject in the REFERENCE section. Here is a pointer to it:

Cockpit Sump Pump

jimh posted 06-02-2011 09:45 AM ET (US)     Profile for jimh  Send Email to jimh     
The description of a switch as "a two-way switch" does not provide enough information to understand its exact configuration. It is possible for a switch to have only two positions yet have different electrical configuration. Switches are usually described in terms of their poles and throws. The simplest switch is a single-pole single-throw (abbreviated SPST). It has two terminals and simply either makes a connection between them or does not. This type of switch is also described as an ON-OFF switch.

It is also possible to have switch with the configuration single-pole double-throw (abbreviated SPDT). Such a switch will have three connections: a common connection and two isolated connections. The switch connects the common to one of the two other connections in one setting, then connects the common to the second connection in the alternate setting, disconnecting from the first. Such a device has three terminals but only two states. This type of switch is also described as an ON-ON switch.

In order to know if there is any opportunity for you to control your device with your switch, we will need to know the details of the switch.

A proper switch for controlling a bilge pump is not very expensive, as marine devices go, so if the current switch is not suitable you could probably replace it with one that was suitable for about a $10 to $15 cost and a few minutes of installation and reconnection.

The general arrangement of the control of a pump for clearing water from a sump or the bilge of a boat is to use a three-position switch with the configuration of ON-OFF-ON(MOMENTARY). This convention is just about universal. I don't see a great deal of advantage or value in trying to adapt a switch with a different configuration for use in controlling the pump, and, as I mentioned, the cost of the switch is insignificant when compared to the total cost of ownership of the boat. On that basis I can't see much benefit to going to any effort to avoid just buying the proper switch.

Mark D posted 06-03-2011 08:43 PM ET (US)     Profile for Mark D  Send Email to Mark D     
I bought a Cole-Hersee three-position pull switch. There are no instructions with it. I don't know what terminal goes to what. $19--you were right. Anybody done this? I am using a Johnson Electrical Float Switch. It has three wires: Brown, Black and Brown-Red-stripe. According the instruction with float switch the Brown-Red-strip goes to the pull switch, the solid Brown goes the brown from pump and pull switch, and Black goes to ground on pull switch. Since there is nothing labeled on pull switch I am stuck.
Bulldog posted 06-04-2011 10:45 AM ET (US)     Profile for Bulldog  Send Email to Bulldog     
You are close. I installed the same switch in my Whaler to eliminate the seperate switch and to have all the switches the same. There is no ground or negative on the pull switch, there is only three connections: power, load 1, and load 2. The switch should be hooked up that pushed-in is off, one-pull-out is automatic and all-the-way-out is manual. The ground or negative from the pump goes to your negative bus or to the battery. The other two wires go right to the switch, and the power for the pump goes to the third screw. The best way to do this is with a continuity meter to see which screw is feed and which are loads. Jim's reference article should get you through this. One thing to remember is a switch will never have a negative terminal unless it is illuminated--Jack
jimh posted 06-06-2011 06:12 AM ET (US)     Profile for jimh  Send Email to jimh     
Cole-Hersee makes many switches. They identify them with a number. They publish an electronic catalog that shows their parts and their electrical arrangement.

I have also written an article with information about Cole-Hersee switches. See my article

Navigation Lamp Wiring

and under the subheading Cole-Hersee Switch you will find information on Cole-Hersee switches and their on-line reference material.

Or, if you know your way around with a multimeter, deduce the switch contact arrangement with a few continuity checks.

Mark D posted 06-07-2011 05:35 AM ET (US)     Profile for Mark D  Send Email to Mark D     
Here's my switch:

I will post the P/N when I find package.

Mark D posted 06-07-2011 05:42 AM ET (US)     Profile for Mark D  Send Email to Mark D     
Here's the link to the switch. Although I did not find any further info on it:

newt posted 06-07-2011 04:29 PM ET (US)     Profile for newt  Send Email to newt     
Yes, I believe that you could use that M531 switch for your bilge pump. It is not the ideal switch to use, and it is a more capable switch than you need, but it should work.

From the Cole Hersee website description, your switch is off-ON A&B-ON B&H. You will not use terminal B. Follow the wiring diagram here: .

Connect the wire labeled BRN w/BLK to terminal H and the wire labeled BRN to terminal A.

When you pull the switch out one click, power will connect to the float switch and you will be in automatic mode. Pull the switch out to click 2, and power will flow directly to pump and you are on in manual mode.

Mark D posted 06-07-2011 05:09 PM ET (US)     Profile for Mark D  Send Email to Mark D     
Thanks to everyone who contributed to the thread. I am using the original two way pull switch after all. If you click on link below you will find a simplified schematic of what I did. My pump now works either by automatic float switch and/or pull switch. Its fully automatic and fully manual. The only thing missing from the drawing is the 15amp fuse I added power lead between the float switch battery. Since the boat sits on mooring it has to have a auto float switch. 47b8d611b3127ccec4a82bfa661600000040O02BbM2rJsxZA9vPhY/cC/f%3D0/ps%3D50/ r%3D0/rx%3D550/ry%3D400/

jimh posted 06-07-2011 05:18 PM ET (US)     Profile for jimh  Send Email to jimh     
Wired as shown in Mark's diagram, the pump is always in its automatic mode. The switch just overrides and forces the pump ON manually. The switch does not control the pump, as it cannot turn off the pump.
Mark D posted 06-07-2011 05:34 PM ET (US)     Profile for Mark D  Send Email to Mark D     
When I lift the float switch to simulate water flooding the bilge the pump comes on; that is good thing. When I release the float switch to simulate the water level gone [down] the pump turns off. I don't really mind that I can't turn off the auto function. It [is] nice to know that I can still operate the pump manually with the pull switch if the float ever fails.
jimh posted 06-07-2011 10:08 PM ET (US)     Profile for jimh  Send Email to jimh     
Mark--I don't see a float switch in your diagram.
Mark D posted 06-08-2011 12:06 AM ET (US)     Profile for Mark D  Send Email to Mark D     
As I mentioned [the electrical wiring diagram linked above] is a simplified sketch. I will draw-up another one in detail to fully illustrate what I did. It will have the pump, switch, and wiring in its completed form.
davej14 posted 06-09-2011 02:48 PM ET (US)     Profile for davej14  Send Email to davej14     
Be aware that you will have a dead battery with this set up if the pump float switch fails in the "on" position.
jimh posted 06-09-2011 09:14 PM ET (US)     Profile for jimh  Send Email to jimh     
As I mentioned initially, a switch with only two positions cannot easily create three states of control in a circuit, and this is the result we have here. The wiring that has been used has only two states for the pump:

--ON, and

--ON but controlled by a float switch

There is no OFF state. This is a worrisome set-up for a boat where the electricity is supplied by a battery. If there is some malfunction in the pump or the float switch, the pump will be running continuously, causing the battery to drain.

It is just about universal on boats for the wiring of a sump pump to have three states of control:



--ON but controlled by a float switch or other automated mechanism

This is the standard practice. Considering there is really no difference in the cost of the switch or the wiring, I cannot see any reason why one would use the two-state control system. It just makes no sense to me. I think it is a mistake, and my opinion is born out by the practice of boat builders for the last several decades.

Mark D posted 06-10-2011 08:42 AM ET (US)     Profile for Mark D  Send Email to Mark D     
I am aware of risk of dead battery. Knowing this it rigged to dedicated battery.
K Albus posted 06-10-2011 09:07 AM ET (US)     Profile for K Albus  Send Email to K Albus     
I believe that my 2002 Dauntless 180 came from the factory rigged with a two position switch for the bilge pump: 1) On, and 2) Auto (i.e., on but controlled by a float switch).

Prior to the installation of a Blue Sea Systems battery switch, the only way to ensure the bilge pump was off was to manually disconnect it from the power source.

jimh posted 06-10-2011 09:17 AM ET (US)     Profile for jimh  Send Email to jimh     
I am surprised that Boston Whaler installed a pump with only two states, and both were ON. I'll have to check their wiring diagrams to see if they are still doing that. On my two Boston Whaler boats with a factory installed pump a three-position switch was used.
davej14 posted 06-10-2011 09:27 AM ET (US)     Profile for davej14  Send Email to davej14     
K Albus,

Are you sure about the two position switch? My 2000 D14 has a three way rocker switch. The center position is "OFF". Pushing the top or bottom of the switch actuates one of the other two "ON" positions as described by Jimh. It is easy to miss that there is a center "OFF" position because the detent of the switch is very light.

jimh posted 06-10-2011 09:34 AM ET (US)     Profile for jimh  Send Email to jimh     
I checked the Boston Whaler wiring diagram on WHALERPARTS.COM, but it did not specify what specific model of switch was used for control of the bilge pump. The switch was wired in a manner similar to the three-position switch that controls the navigation lamps, but there was no indication about how many positions the bilge switch has.
K Albus posted 06-10-2011 09:41 AM ET (US)     Profile for K Albus  Send Email to K Albus     
I am virtually certain that the only three-position switch on my boat is the Navigation/Anchor Light switch. I will check it when I get home tonight. In the meantime, here's a link to the wiring diagram for my boat:
K Albus posted 06-10-2011 05:30 PM ET (US)     Profile for K Albus  Send Email to K Albus     
I have confirmed that my bilge pump switch has only two positions: 1) On, and 2) Auto. This is the way it came from the factory.
Mark D posted 09-07-2011 10:32 PM ET (US)     Profile for Mark D  Send Email to Mark D     
I just wanted to update everyone on my two way bilge pump switch set up. I started the thread a while back. I never could have imagined how much use it got in the month of August and September. With nearly zero rain in June and July the pump got overtime use in August. With with flooding rains in early Aug and then Hurricane Irene's 14 plus inches and now the remnant of Lee I can say the system worked flawlessly. Four year old battery held up and I have no complaints.


Bulldog posted 09-07-2011 11:37 PM ET (US)     Profile for Bulldog  Send Email to Bulldog     
Mark, that's great news, glad it worked out!....Jack
Mark D posted 09-12-2011 07:36 AM ET (US)     Profile for Mark D  Send Email to Mark D     
I was very surprised that after a whole summer is the water the batteries did not even need a charge.

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