Bile Pump Float Switch

J

jhc109

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Sep 24, 2008
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30810
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Yesterday afternoon while doing some routine duties in the engine room I discovered that my bilge pump was on and the pump was hot. I have no idea how long it had been running. I believe the problem is with the Rule-a-matic plus float switch. The float was free and clear of any desbris and it still would not shut off. I finally had to pull the fuse to turn it off. This seems to be a common problem. Has this happened to anyone? What did you replace your float switch with? The West Marine reviews on this float switch are scathing !!!!

Jonathan
 
I went with a Water Witch 101 solid state switch. No moving parts. Appears after a year to work as advertised. I've heard the contrary about it though so do your research.
 
I've used Rhule float switches since forever and never had a problem with them. However, like everything else on a boat, they require periodic attention, i.e., cleaning and basic maintenance. If left unattended, over time, they can built up enough crud in them to either stick them open or stick them closed rendering them inoperable. Also, like everything else on a boat, they do go bad. Contacts can corrode and wiring can become frayed or corroded. So, 2-3 times a year give them a good check and clean them and you should be fine. I also give the bilge pumps themselves a good cleaning once a year.

quote:
Originally posted by jhc109

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the rule float switches are fire.. like everything on a boat they will eventually fail... i like much better to the sure bail with the blue cover which are harder to test.

you should really have a light at the helm to alert you when the pump is on... almost everybody has one, if you don't you should add one asap for all your bilge pumps. Ideally, with a buzzer for when you're not a the helm.
 
Float switches are definitely the weak link in the system. They used to be mercury switches and they did very well. Now they are mostly simply a ball that rolls up and down to make contact. Over the past ten years I have probably replaced 10 switches. I have 3 on my boat. Putting a diode across the switch certainly helps. When the circuit de energizes, the collapsing magnetic fields cause a spike that cause arcing on the ball, A diode prevents that from happening.I ended up doing away with float switches and built purely electronic switching.I have never had a problem since. This summer I intend to play with capacitance chips that are used to run touch screens, If they act as I suspect they will, I should be able to build a switch that has both no moving parts and no requirement for probe to water contact. A big advantage of electronic is that if there is no water whatsoever in your bilge and you get a diesel leak. The diesel will not trip the bilge pump. Possibly saving a large fine.
Bazza.
 
Bazza- The diode trick sounds interesting. I'm curious how you can have a capacitance-based device without a probe that touches water to sense it as for instance the Centroid Products fuel senders do. I don't pretend to know how they work.

Jonathan- Float switches definitely can fail internally, but sticking in the ON position can be prevented by at least annual maintenance of spraying the hinges with WD-40 and exercising the float rapidly, then following up with a couple shots of teflon spray at the hinges. Use a ...little... Dawn detergent or other bilge cleaner in the bilge occasionally too. As the installation pamphlet of htese switches usually note, ometimes float switch screws fastened too tightly or at slight angle to each other can cause slight warping of the hinge bracket and encourage premature sticking as well.
 
Krud-Cutter. Made for vinyl siding wash and it's the best bilge cleaner going. Gallon $5.00 at Walmart. Not sure how good it is for the environment though.
 
Get a Ultimate Float Switch and you'll never have to replace it again. The Senior model even comes with built in wires for a high water alarm.
 
Distilled white vinegar is a great pump de-gunker. I too subscribe to the Ultra switches, as eye-watering expensive as they are.
Of course, we are talking about something that can either sink or float the boat here...
 
I have changed all my float switches (6) to Water Witch. I had them on my other boat for close on 20-years and they never once (seriously) missed a beat. As for bilge pumps that continously run (dry)- my friends pump 2-weeks ago caught fire. No damage apart from smell and mess. But if something had been flammable nearby a different story. Just my .02 worth.
 
I got rid of those darn &*%^$#rb float switches years ago. I upgraded to the newer type that do not require a float switch. It does this by cycling on for a second every few minutes and shuts off if no water is found. They are easy to check without having to go down to the bilge and lift the switch.

Dave
 
I have tried the electronic type that use a single probe and run on for a preset time after they no longer detect water, to prevent short cycling. They have a problem with detergents. If the probe gets water on them that has enough detergent in it then they do not sense when the water is gone and keep the pump on...Bad! The type that just test for current draw every so often by cycling the pump have a downfall if you have a perfectly dry bilge, in that they eventually destroy the shaft seal and then when you do get water in the bilge the pump then fails.... Bad! Some of the switches that use 2 electrodes are an electrolysis trap. I have come across a couple that have a permanent supply to one of the probes. Sure its through a resistor of many hundred k but there is still a risk.The better ones have the lower probe as a grounded probe. The ones I have built for my boat use 3 probes. There are 2 lower probes and one higher probe. One of the lower probes is directly connected to ground. The second one goes to a bilateral switch that keeps it at ground level until the pump is activated. The third probe which is higher up than the other 2, is the high side probe and is always out of any water, up until the water level is high enough to start the pump. When the pump start the bilateral switch activates the second probe and the pump runs until the level drops below the second probe. Depending upon the difference in probe lengths, the on and off levels are selective. On some of my pumps I have a forth probe that is higher again. If this one gets wet then it activates a much larger pump and high water alarms. All switching is done by relays and all have free wheeling diodes on them. I have not had i single problem since I installed them. Now why cant a manufacturer produce something with some thought to it?
Bazza.
 
The type I use do NOT have any probes or switches at all. They work simply internally by monitoring the current the motor is drawing. With water present, the pump motor draws more current and when the water is gone, the motor current drops and the pump shuts off. I love them. :-)

Dave
 
I like to know how often the pumps cycle...With the "auto" types, you cant get an accurate count.
I'm still a fan of the old rule float switches. I like to be able to test them by lifting the float and know the pump comes on.
Also, If I went to an auto, I'd be up every time the pump switches on to check.

John
 
Mine cycles on and off about every one to two minutes. I don't know why you would need an accurate count unless your trying too see how much water is leaking into the bilge.

Mines very easy to test. I don't have to go down to the bilge and lift a switch. Just turn off the CB on the fuse panel and turn it back on. Watch the DC MA meter go up about three amps and then shuts off. I know it's working and no water is in the bilge.

"Up every time the pump switches on to check"
It's midnight and you wake up. Do you know if your bilge pump is working?? I do because if I wait a minute or two I can hear a very slight humm of the pump motor coming on and cycling off a second later. Now I KNOW the pump is working and there is no water in the bilge.

Dave
 
Yes..I have a counter on the pump to help keep an eye on dewatering, particularly helpful if you are away from the boat for any length of time. If the pumps are doing their job, you could check and find no appreciable water even though the system has pumped gallons while you were gone.

Also, just because the pump (motor) runs doesn't mean it's actually pumping and/or that the water has been removed...I had a "auto" type like you have described and it became clogged with some dog hair. No "load" was seem by the pump so it shut off.

If I hear a pump come on at night, it darn well wakes me up. There are about a dozen sounds that I'll sleep right thru, but the pumps coming on aren't one of them. If it was one of those "every few minute lemme check" types, I'd either; a) never fall asleep or, b) file it as background noise after getting used to it.

It's a personal preference on my part...
 
A switched pump can become folded with dog hair just as easily.

The noise mine creates is very suttel and you really have to listen for it.

To each their own and that is fine. I just have had to many failed/fowled switches,just as the origanl poster of this thread has had,over the years and for the main pump will never use them again. I still use them for secondary pumps and also the shower sump.

Dave
 
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