Auto-Sensing Pump and Three-Way Switch

[pcloward]

I purchased a bought a RULE pump with automatic water sensing. I want to connect the new pump to the existing three-way switch on my boat.

The RULE pump has three wires with the wire insulation colors Black, Brown, Brown with White.

[Moderator’s note: the circuit is now going to be described in a narrative.]

The wire with Black insulation goes to the indicator lamp on the switch, and not direct to ground, according to the
Instructions.

Q1: is the instruction to connect the black wire to the lamp on the switch panel correct?

Fig. 1. Instructions.

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Fig. 2. The three position switch, panel, and lamp.

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Fig.3. Wiring on switch.

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[jimh]

Q1: is the instruction to connect the black wire to the lamp on the switch panel correct?

I don’t see that advice given in the instructions.

[pcloward]

According to the instructions I would ground the black wire, however the black wire for the old pump is connected to the indicator light on the bilge pump switch. Then there is black jumper from the light down to the brown wire.

I have search all sorts of manuals and online resources & have not seen this configuration.

Maybe the old switch will not work with the newer auto bilge.

Paul

[jimh]

From what I can see from the instructions shown in FIgure 1, the pump you have purchased works in the following manner:

• the BLACK conductor from the pump MUST be connected to the BATTERY NEGATIVE at all times;
• the BROWN conductor from the pump is to be connected to a source of 12-Volt positive power when you want the pump to operate AUTOMATICALLY, that is, when the pump senses water and initiates and terminates its own operation;
• the BROWN with WHITE conductor is to be connected to a source of 12-Volt positive power when you want to cause the pump to operate no matter if it has sensed water or not.

The LAMP on the original control panel for the previous pump, which indicated to the operator that the pump was receiving electrical power, cannot be used with the new pump without additional circuitry. If you wish to use the lamp with the new pump so that the lamp will illuminate when the pump is receiving electrical power, you will have to add two steering diodes to the circuit. I can explain this further to you if you feel like you will be sufficiently skilled in electrical wiring to accomplish this modification. Generally, anyone familiar with electrical DC circuits would deduce the need for the two diodes themselves, and would immediately know where and how to install them.

I do not know how the pump you have purchased operates, but below I explain the general method used by these small centrifugal pumps that are sold as having an automatic operation mode.

HOW A SELF-OPERATING PUMP KNOWS WHEN TO RUN

The pump employs an internal controller to run the motor. The amount of electrical current drawn by the motor to spin the pump will be very low if the pump is not immersed in water, because the impeller in the pump will be spinning in air. If the pump is immersed in water, the impeller will be trying to move and lift water upward. This imposes a much greater load on the pump motor, causing the pump motor to require more electrical current. This difference in electrical current is the basis for the pump controller to detect if there is water that needs to be pumped out. When the pump actuates spontaneously to test for water, if the motor draws very little current the pump internal controller decides that there is no water, and it shuts off the pump. The pump remains inoperative for a pre-set amount of idle time determined in the controller circuitry. When the idle time period has expired, the pump again spontaneously goes into operation, and the cycle is repeated.

When the pump self-actuates and the motor draws more current than the threshold level set in the internal controller, the pump continues to operate, as it has decided there is water to be pumped up and out. When the the pump has removed water from its intake to a sufficiently low level of water, the electrical current will reduce below the operating threshold, and the motor will shut off. The controller than repeats its normal testing for water at preset intervals

The instructions show two additional components. First, a FUSE is installed in the power source from the boat battery in order to protect this branch circuit from current overloads.

Next, a switch is shown in a poorly drawn manner. The diagram in the instructions is not very useful, and it contains very little information regarding the switch itself.

Generally, there has been a useful wiring of a switch related to operation of a pump, and Boston Whaler has used this method. I describe it as follows:

• a single pole three-position ON-OFF-ON (MOMENTARY) switch is used
• +12 Volt power is provided to the switch COMMON
• the switch ON terminal provides power to operate the pump through a separate controlling device, usually a float switch; this is the AUTO position;
• the switch ON MOMENTARY contact provides power directly to the pump motor while an operator holds the switch in this position; this is the MANUAL position;
• if the the switch is left in the OFF position, no power flows to the pump motor.

Assuming the existing switch is the same as I have described, you can re-use the switch. From the description above it should be easy to deduce which wire colors from the pump go to which terminals on the switch. If you need more help with this, reply and I will get into even greater detail.

The general problem with a pump of this type is its relentless consumption of electrical power because of its periodic testing for water. If you leave the pump control switch in the AUTO position, the pump can run for testing for water for many cycles, each one consuming electrical power from the battery. If left in this configuration for enough time, the current drained from the battery will remove stored electrical energy from the battery and eventually cause the battery to become discharged.

My recommendation to you is as follows:

• return the pump you have purchased and get a refund
• buy a replacement pump without the silly automatic self-actuating feature.

MORE INFORMATION

More information about the circuitry used by Boston Whaler to control a sump pump with a three-position switch can be found in the REFERENCE section article on that topic. See

https://continuouswave.com/whaler/refer ... ePump.html

[pcloward]

I really appreciate your thorough reponse. You cracked the code I code not: The switch won’t working properly (without modification) with the current pump. I did find this one, which should, for only $40.

https://www.xylem.com/en-us/brands/rule ... el-switch/

I do like the safety feature of seeing on the dash when the pump is turned on.

Also, I agree with your advice to switch back to a regular pump and a separate sensor, the only challenge is the crowded bilge space on this Boston Whaler. Both items do fit, but it’s cramped for sure.

So, for now: I will run that negative straight to the battery & use the old switch, then eventually replace it with the one from Rule.

ASIDE: You and this forum have been helpful to my refit of this 19 Guardian - Thank you.

Of note: From what I can tell the boat was used by the National Park Service on the Potomac River. I got it an auction back east. Kinda cool history.

[jimh]

According to the instructions I would ground the black wire, however the black wire for the old pump is connected to the indicator light on the bilge pump switch.

I believe you are imputing too much significance to the wire insulation color on the lamp leads being black. The notion that the lamp leads are provided on wire with black insulation should not be imputed to mean there is a correlation between those leads and a lead provided by the pump manufacturer which happens to also be implemented using wire with black insulation.

[jimh]

I did find this [three-position switch], which should [work properly with a RULE automatic pump], for only $40

At today's inflated prices of everthing, a $40 switch with an attractive bezel that only costs $40 is an incredible bargain. You should buy one.

[jimh]

You can use the existing switch and lamp, but you need to add two diodes. The cost of the diodes will be less than a dollar.

The anode of one diode (D1) will connect to the BROWN conductor from the pump.

The another of the other diode (D2) will connect to the BROWN with WHITE conductor from the pump.

The cathodes of D1 and D2 will be connected in common with one of the BLACK leads from the existing LAMP; the other BLACK lead from the existing lamp will connect to battery negative.

You can use just about any small diode for this purpose. For example a 1N4001 diode that costs about $0.20 will work.

HINT: the marking on the diode that looks like an arrow is the cathode; the marking on the diode that looks like a bar is the anode.

HINT: you can wire the diodes at the switch terminals.

ASIDE: the cost of shipping and handling to order two $0.20 diodes will be much greater than the actual cost. Look for a local electronics parts store, order from Amazon Prime, or ask a friend who has a background in electronics if he has two suitable diodes he can give you for a beer.

[pcloward]

At today's inflated prices of everthing, a $40 switch with an attractive bezel that only costs $40 is an incredible bargain. You should buy one.

I was surprised the switch was only $40. I have figured I better go first-rate with the sump pump setup, and particularly because the coastal waters off California tend to get a little sloppy.

I appreciate the electrical information provided.