3 WIRE BILGE PUMP FLOAT SWITCH

EzGoinFlGuy

Recent development, bilge full of water! Turns out the Johnson float switch was not activating the pump. It's a 3 wire switch and has some kind of float inside the sealed plastic housing. I wanted to get a switch with newer technology and no moving parts. . So far the marina has come up with a sealed unit with no moving parts, but only has 2 wires. I believe the old float switch has 3 wires for a reason, unless there's a way to wire it in and still maintain continuity for the lighted dash switch to work properly. My question is has anyone done a similar upgrade?

 

This may be an old issue, but didn't see any in past discussions. 

EZ

PS

Me and my I-Pilot are getting along just fine.  )

 

nquirk

EZ, glad to hear you and the I-Pilot are getting along

On the 3 wire switch, you have your neutral ground.  In addition, the other two wires provide power.  The first is wired to your switch panel where it will toggle on/off.

The other, leads directly to the positive terminal of your battery (with an inline 4A fuse I believe for those Johnson pumps)

I've never worked with a 2 wire, but suspect for it to work with an inline switch, you'd need a 3 way switch for on/off/automatic which would then use your inline breaker for protection.

Was the float switch in the Johnson pump not working?  These pumps are very reliable but have two things that are critical for continued operation (in my opinion)

At the start of the season do the following:

- check the inline fuse for any corrosion, etc in the holder (99.9% of the time, this a problem)

- add water to your bilge and run the pump manually via the switch.  If it doesn't pump water out (assuming no blockage in the hose) listen to see if the pump is spinning.  If not, remove it from its housing and manually spin the impeller.  0.09% of the time, gunk sticks the shaft on the motor (especially if its stored for months at a time like us Northerners who can't boat at -20 degrees)

The remaining 0.01% of the time, the pump is failed.

 

EzGoinFlGuy

Thanks NQ,

The float switch is mounted next to the pump & was intermittent. The pump is fine. Talked to a marine tech where  I bought the float switch and he says to join the two power wires to the one at the switch.. Whoa! That's a big red flag!! That doesn't quite compute, there are 3 float switch wires on the switch for a reason!. Guess I'll get in touch with the manufacturer tech support.. At least presently, I can depend on the helm bilge switch.

EZ

nquirk

EZ, taking a three wire on a pump and combining the switched power and the float switch power together to have it only in manual switch mode is fine. (3 wire pump to two wire switch)

However, in reverse, what he's suggested would put both a switched and constant power to the power input of the switch.  (3 wire setup to a 2 wire switch)

I assume this 2 wire switch has a float switch in it.  If not, then its simply a manual pump and the connection direct to the battery is unnecessary.

What he's suggested (again I don't know the pump but if you could post make/model as I'm curious) SHOULDN'T work.  Here's why (again my simple thinking).

The wire from the helm switch, will only complete the circuit and provide power when the switch is ON.  (THIS IS A GOOD THING)

The wire to the battery (with an inline fuse), will provide a constant power to the switch.  Which means the pump will run constantly.  (THIS IS A BAD THING)  It needs constant power but the switch part needs to be the float switch triggered by water level rising.  Simply test is connect the three together with helm switch OFF and the switch in your hand.  If it runs, its the wrong setup.

My guess is this switch doesn't have moving parts because it doesn't have a float switch which is why no third wire exists.  I don't know any other mechanism to do both which is why I'm very interested in the make/model of switch.

EzGoinFlGuy

Thanks NQ,

Have not had another chance to play with it, but when I do and get the right combination where things work as they should, I'll post a diagram.

(Johnson 1000 GPH and Johnson 3 wire float switch)

 

EZ