Opinions on float switches?

Having a bit of trouble with my float switch. Sometimes won't come on, and then last night after all the rain it came on and didn't turn off. Fortunately not a major problem as the boat's out of the water at the moment, but the last thing I want is a drained battery and burnt out pump just before I go to use the boat.

Now this may not sound like a major deal, but the switch (well the boat as well actually) is only three weeks old, so it shouldn't be giving me any grief yet :eek: The pump and switch are made by Piranha Shur-flo and I thought looked quite reliable. Clearly not. The plastic casing seems to have gone a bit rough, almost like lime-scale which may not be helping. Needless to say I'm trying to contact the boat maker ProSport... (you'll know this is easier said than done if you've read any previous posts) and I've already spoken to Shur flo.

So the question is... after all the waffle above... what's the most reliable make or type of float switch?

I get the impression that float switches arn't the best in the world.......

You can get some switches that work on electricty passing through two little terminals when the water level rises (someone give me the proper name!). This has no moving parts and is probably a much more reliable sort than the float sort....

yes thats what youu want it's the only one I have found reliable.

It's made by Jabsco and it's called a hydroswitch

http://www.jabsco.com/prodInfoApp/servlet/DisplayItemDetail?itemId=59400-0024&catalogId=Marine&categoryId=BILGE&typeId=JMBPA

Having a bit of trouble with my float switch. Sometimes won't come on, and then last night after all the rain it came on and didn't turn off. Fortunately not a major problem as the boat's out of the water at the moment, but the last thing I want is a drained battery and burnt out pump just before I go to use the boat.

Now this may not sound like a major deal, but the switch (well the boat as well actually) is only three weeks old, so it shouldn't be giving me any grief yet :eek: The pump and switch are made by Piranha Shur-flo and I thought looked quite reliable. Clearly not. The plastic casing seems to have gone a bit rough, almost like lime-scale which may not be helping. Needless to say I'm trying to contact the boat maker ProSport... (you'll know this is easier said than done if you've read any previous posts) and I've already spoken to Shur flo.

So the question is... after all the waffle above... what's the most reliable make or type of float switch?

I had the same prob with the Piranha, took it back into the marina ang got a new one that was better it lasted 4 weeks, so changed it for a Jabsco...no probs since.
Andy

Thanks for the replies. I've been sent a replacement so I'll see how long that lasts before I try an alternative.

Lets have a sweepstake. I've reckon 150 hours on the water

If float switches are unreliable is the 'Hydroswitch' a worthwhile upgrade ? I checked out the website but did not see a price, how much are they ? Are they 24v only ? I have just bought a Pro Sport and am keen to eliminate any gltches before they happen. Erin, you seem to have had a response from Pro Sport as you mention a replacement is on it's way within 24 hours of posting the start of the thread mentioning difficulty in getting service.

If you are able, make one. The pic below is the circuit I used for mine. Sorry it's a bit scruffy but it's all there.

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27-08-04 Edit: Updated at Wave's request.

The circiut is very simple to build on a small piece of vero. The TIP122 is a darlington power transistor but it is not strictly necessary, I just happen to have a bag of them. I would use a darlington though, it gives a good clean switch on of the relay.

The board can be housed inside a waterproof box. B&Q have a range of them which use gland nuts for the cables

Jeff 3/10 (see me) you couldn't do that again in a darker colour could you?


Scottydog I have found float switches/ auto bilge pumps to be extremely unreliable. I believe it is because the switch contacts are immersed in water and although sealed osmosis erodes the contacts.

The hydroswitch is different in that the switch and contacts are a long way from the water 100 cms and therefore doesn't degrade so quickly. the switch is a passive one so the rating of 24 volts means it can handle 24 v circuits but it will work fine on a 12v

Just getting ready to kit out my new xs-550 and came across a solid state switch that senses the water level.It's completely sealed in plastic with no moving parts and would appear to be ideal for RIB applications.
It has 2 raised circles marked on the case ; the higher one being the on marker(2" up ) and the lower ,being the off level.(3/4" up)
Will handle pumps up to 20 Amps and comes with a 3 year limited warranty.
Also easy to test ; you put two fingers on the raised circles to switch on/remove the top finger pump stays on/remove bottom finger and turns off after short delay.
So thought it was worth a try and will let you know how it performs.
cheers Dal

If you are able, make one.

Thanks for the schematic, I had already thought there may be a need for some electronic solutions to sort out common problems. If I get time I shall knock one up and maybe a couple of spares that anyone else can have (free) to see if it cures the problem, 'evaluation' kind of thing. I have great facilities for building kit for harsh environments so may have lots of little projects on the horizon.

I shall look through the posts and try to find some other problems that may only require simple solutions, let me know if anyone has such a suggestion. There must be loads of cases in need of remedy.

This was very recently discussed - the best bet seems to be the following

http://www.waterwitch.info/

http://www.penguinfrigo.co.uk/default.shtm

As posted by SWIFT.

looks worth a try!

Jeff 3/10 (see me) you couldn't do that again in a darker colour could you?


Teachers do it in red!

Actually, I've hung up me pen so I suppose I could do it neatly, just for you. :p

Done.
A couple of wee mods to the above diagrams for those who drop spanners.
If I can get around to it, I'll put a circuit together where the probes short to ground to trigger the relay. A bit more failsafe, I think.

10/10 well done

I use a Rule automatic Bilge pump and find it great (no probs yet anyway!)

Its fully electronic and doesnt use probes or float switches but instead tries to pump every 2.5 minutes. If there is water present it continues to pump until the sump is empty then stops.

The electronics senses the load on the impeller and therefore knows whether water is present.

It pumps 1100 Gallons / Hour.

I tend to leave the battery switch on when the boat is in the water but unattended. So far I have left it for about 10 days in a row and the 110Ah battery was fine. (Draws very little current when in check mode)
Not cheap though - about £85 I think but then if you add a decent pump and seperate switch together I bet you wouldnt get much change out of £85 anyway.

Well worth considering in my opinion!

Nick

Whilst noot quite on the subject this is a link to a US site with reports on bilge pumps
http://www.powerboat-reports.com/sample/bilge.html
Rgds
James

Cheers everyone.

I shall take a close look at JW's circuit and maybe see if I can build one. If not I'll happily evaluate one for ScottyDog.

And yes ScottyDog, I did get a reply from Prosport within 24 hours. I couldn't get through on the phone of course ;) but sent a fax instead asking them to give me a call, and lo and behold my phone rang the next morning :D . Still took 5 days for the replacement to get to me, but that's probably something to do with Guernsey Post stockpiling parcels until they feel like sending them the 20 miles or so to their sister island.

I use a Rule automatic Bilge pump and find it great (no probs yet anyway!)

Its fully electronic and doesnt use probes or float switches but instead tries to pump every 2.5 minutes. If there is water present it continues to pump until the sump is empty then stops.

The electronics senses the load on the impeller and therefore knows whether water is present.

It pumps 1100 Gallons / Hour.

I tend to leave the battery switch on when the boat is in the water but unattended. So far I have left it for about 10 days in a row and the 110Ah battery was fine. (Draws very little current when in check mode)
Not cheap though - about £85 I think but then if you add a decent pump and seperate switch together I bet you wouldnt get much change out of £85 anyway.

Well worth considering in my opinion!

Nick Glad to hear that nick just fitted one of those.:)

Thanks for the schematic, If I get time I shall knock one up ....

ScottyDog, I missed this post.If you're going to make one use a PNP darlington and put the probes from the base to ground. That will prevent there being a voltage sitting on one probe. TIP 125, 126 & 127 are PNP's.
That'll save me a job . :)

Its fully electronic and doesnt use probes or float switches but instead tries to pump every 2.5 minutes. If there is water present it continues to pump until the sump is empty then stops........ So far I have left it for about 10 days in a row and the 110Ah battery was fine. (Draws very little current when in check mode)We've left a boat in the water from Xmas to Easter using one of these pumps and the battery lasted for that length of time - just about (just enough charge left to turn the engine over a few times). I think that they do operate at full current for the test phase, but only for a short time (about 5secs IIRC).

The bilge pump circuit described above has a flaw. It does work and the pump will certainly switch on as planned but, depending on the relay used, it may not switch off for a while. The reason appears to be because a relay requires more current to pull it in than it requires to hold it in. When water is sensed the pump switches on. When the water level falls from the sening probes they will be damp and this dampness may still be conductive enough to hold the relay on. The reason for using this type of circuit was to limit the current consumption to almost zero when the boat is not in use.

A better circuit is given below but it is active in that it consumes some current at all times, however, in the two I have built, this is only 1.9mA. (0.0019amps)

It is a straight forward comparator but using the CA3140 op-amp which consumes very little current and it is also good for use on a normal battery supply. The wee circuit on the output from the op-amp simply ensures that any raggedness in the supply or across the probes does not cause rapid on/off switching but it doesn't introduce hysteresis. By increasing the value of the capacitor it is possible to cause the pump to switch on for a minimum length of time, say 5 seconds, if this is felt to be an advantage.

They have been tested in anger (Had a fkkn leak!) and they worked a treat.

Calibration was done by soldering a couple of bits of offcut wire where the probes connect to the board and dipping them into a glass of fresh water. The preset is then turned until the LED lights and then turned a touch more to ensure a positive trigger. I thought that this would probably need to be recalibrated for salt water once in the boat but it worked fine.

Oops... missed out the 1k resistor in series with the LED and a break in the +ve track.

Hi JW

Time for a Maplin order I think. Thanks for the design.

Cheers
Keith

:D :D :D

I built jw's latest design and it works a treat. Now all i've got to do is waterproof it all and fit it.

Thanks jw.

JW

Fair play you have spent more time and energy working on a system that took me many years. Most of the vessels we own or supply are deep water moored and an efficient bilge system in force 9 plus is of significance to the point that we always fit a twin bilge with independant batteries.

Auto systems tend to work on various number of principles

1. A merc switch
2. Mechanical ball switch
3. Earth resistance
4. Back pressure sensor.

One of the important points to any system is the delay in detecting a water level and the intruction to start pumping. This is why we like the computerised method as it avoids false starts in a heavy sea.

After many years we have found the Rule 2000 and 3000 computerised systems the best and they work on back pressure sensor. Of over 50 supplied we only last week had the first one returned. Of caution though the filter in the base must be checked on a regular basis and the major failure with all pumps is human hair---- it falls onto the deck, goes aft into the well and when spinning round the pump makes a very strong rope. So every so often turn the pump upside down and pick the hairs out !!..... dont let your wife do it in case its not the same colour as her hair !!!!


Cheers

John
www.quinquari.co.uk

Cool.

A wee update on auto bilge pump sensors.

This one was designed for a particular purpose. It triggers as the bilge water comes into contact with the sensing probes and the pump runs for a period of time which is adjustable up to approximately 10 minutes. To prevent mistriggering by slopping, the pump will not start to run until the sensors have been in contact with the water for a few seconds.

It's purpose is to allow the bilge water to rise to a predetermined level and then pump it out completely rather than having a pump cycling frequently.

In standby, the circuit draws a tad less than 4mA so that shouldn't be a concern.

Depending on one's preference, fuses can be fitted.

Electronic components can now be sourced online from here at Rapid Electronics (http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=20589). Just set up an account and pay by credit card.