PDA

View Full Version : No more cheapo float switches



pcatterall
22-10-12, 18:26
Just doing the winterisation jobs and taking some care as we are afloat and far from home!!18 months ago I fitted a float switch which failed after 6 months I then fitted another and then a second one higher up. |Belt and braces I thought. I have checked them from time to time and they were ok.
Now, of course putting the boat to bed I found that niether of them worked.
Removed them and played about for a while and one decided to work but not the other.
They were admittably fairly cheap items ( one is SeaFlow the other has no name but they look identical.
I know the maxim about getting what you pay for but often I see more expensive kit looking as cheaply made as the cheap stuff.
So are there any recommendations out there please and also a supplier who will post out to me in France.
Many thanks

sailorman
22-10-12, 18:48
i am reliably informed that these are the DBs
http://www.bilgeswitch.co.uk/

rtboss1
22-10-12, 18:55
i am reliably informed that these are the DBs
http://www.bilgeswitch.co.uk/

All I get, is being directed to Homestead web building .
Where can i buy the product

cheers bobt

sailorman
22-10-12, 18:59
All I get, is being directed to Homestead web building .
Where can i buy the product

cheers bobt

http://www.ebay.co.uk/itm/WATER-WITCH-12-VOLT-ELECTRONIC-BILGE-PUMP-SWITCH-12v-BOAT-NEW-/140824918005?pt=UK_CarsParts_Vehicles_BoatEquipmen t_Accessories_SM&hash=item20c9d1b7f5

winsbury
22-10-12, 19:01
http://www.seamarknunn.com/acatalog/info_CU18133.html is cheapest I can find.

nigelmercier
22-10-12, 23:04
Not sure about the Water Witch. I don't like the idea of submerged electrodes in my bilge, and I'd be surprised if they worked if coated in oil.

I know you can get a device that polls the bilge pump to see if it has a load, and deals with the result accordingly. It's on my list of electronics projects to make one.

sailorman
22-10-12, 23:08
Not sure about the Water Witch. I don't like the idea of submerged electrodes in my bilge, and I'd be surprised if they worked if coated in oil.

I know you can get a device that polls the bilge pump to see if it has a load, and deals with the result accordingly. It's on my list of electronics projects to make one.

we dont have oily bilges thank you very much :p
we do get rain water via the mast sheave box`s though :)

The Dogs Pollacks Brother
23-10-12, 08:09
Go for the super sub 500..........NO float switch or other moving parts, it works of a sensor (some kind of proximity switch I guess?) Its a long cylindrical shaped jobby so it fits neat and snug low down wherever you want it.
It was the only thing we took off the last boat to keep!

pcatterall
23-10-12, 08:27
Thanks guys. The 'Water witch' type look to have 3 leads. I really just need a switch which is open circuit when off then closed when actuated ( commomly just two brown leads) so as to fit into my alarm and switch circuit.
I guess that at this time I want a good quality conventional 'mechanical' type ( if this exists!!)
It was 'alarming' to find that both switches were US especially as the upper switch has never even been submerged.
I will chop up the lower switch to see if I can determine the cause.

sailorman
23-10-12, 08:40
Thanks guys. The 'Water witch' type look to have 3 leads. I really just need a switch which is open circuit when off then closed when actuated ( commomly just two brown leads) so as to fit into my alarm and switch circuit.
I guess that at this time I want a good quality conventional 'mechanical' type ( if this exists!!)
It was 'alarming' to find that both switches were US especially as the upper switch has never even been submerged.
I will chop up the lower switch to see if I can determine the cause.

2 wires for power to the circuit 1 switch wire

wotayottie
23-10-12, 08:57
I guess that at this time I want a good quality conventional 'mechanical' type ( if this exists!!)

A mechanical switch will always be less reliable than a solid state sealed electronic switch.

PilotWolf
23-10-12, 09:01
Can't remember where I saw them or if they were even commercially available but they were based on a washing machine part. It consists of a plastic tube with a pressure sensor at the top. The bilge water compresses the air in the tube and via a relay it turns on the pump.

W.

Salty John
23-10-12, 09:46
The Jabsco Hydro Air Switch was given high marks in a test of switches conducted on behalf of the UK fishing industry. The Water Witch also came out well in the tests.

Six months in the bilge of a North Sea trawler must have given these switches a good test!

I blogged about it here:
http://saltyjohn.blogspot.co.uk/2012/07/bilge-switches.html

Niander
23-10-12, 10:22
http://www.ebay.co.uk/itm/NEW-JOHNSON-ULTIMA-BILGE-PUMP-AUTO-FLOAT-SWITCH-/330647984069

greenalien
23-10-12, 10:35
You could always make your own - just need a magnet and a reed switch,
only need to bring the magnet and switch into proximity to close the switch; the switch would need to be well sealed against water ingress, then should be very reliable.
However, I wouldn't switch the bilge pump directly from a reed switch, I'd use the reed switch to activate a relay, then use that to activate the bilge pump.

lw395
23-10-12, 11:17
You could always make your own - just need a magnet and a reed switch,
only need to bring the magnet and switch into proximity to close the switch; the switch would need to be well sealed against water ingress, then should be very reliable.
However, I wouldn't switch the bilge pump directly from a reed switch, I'd use the reed switch to activate a relay, then use that to activate the bilge pump.

I've found relays to be not that reliable in a marine environment.
You can get cheap reed/magnet float switches. I've used mosfets to buffer them to drive bilge pumps.

lw395
23-10-12, 11:21
T....

Six months in the bilge of a North Sea trawler must have given these switches a good test!
.....]

Six months is only six months.
It's probably several degrees colder in the North sea, so that's only worth half a season in the bilge of a Solent keelboat.

All these things lead short and not very glorious lives!
I don't believe there is such a thing as fit'n'forget when it comes to bilge pumps.

markdj
23-10-12, 12:00
I'd suggest the Rule switch

http://goo.gl/qmOkS

There is also a heavy duty one for higher amperage and an enclosed one for better protection of the float.

lw395
23-10-12, 12:04
I'd suggest the Rule switch

http://goo.gl/qmOkS

There is also a heavy duty one for higher amperage and an enclosed one for better protection of the float.

I've seen quite a few of those fail, they typically last between 1 and 2 years in the harsh environment of a dayboat or RIB.

rtboss1
23-10-12, 12:15
I'd suggest the Rule switch

http://goo.gl/qmOkS

There is also a heavy duty one for higher amperage and an enclosed one for better protection of the float.

I have two of those, I find that probably one time in twenty they fail to operate.
That the biggest worry about leaving the boat and I have dry bilges.when moored ,water does enter the rudder stock when under way as the stern drops.

greenalien
23-10-12, 13:04
I've found relays to be not that reliable in a marine environment.

As long as you keep them dry, shouldn't be a problem. I like these -
http://www.ebay.co.uk/itm/12v-ac-dc-Handy-little-Relay-board-ideal-for-security-/110957533328 - nice and easy to connect up, and cheap enough to make carrying a spare an affordable option.

There's only a few reasons why a bilge pump switch can fail - mechanical failure, water leaking into it, or the switch not having sufficient current-carrying capability to handle the load of the pump, and getting burned contacts. I suspect the latter problem is quite common, that's why I'd always recommend connecting the pump via a relay (or Mosfet, as suggested).

DaveS
23-10-12, 19:09
Can't remember where I saw them or if they were even commercially available but they were based on a washing machine part. It consists of a plastic tube with a pressure sensor at the top. The bilge water compresses the air in the tube and via a relay it turns on the pump.
W.

Yes, a common arrangement in washing machines and dishwashers. For increased sensitivity use an "air bell", i.e. a short capped pipe in the bilge, open end down, connected by a narrower tube to the air pressure switch mounted somewhere dry.

Ridax
24-10-12, 05:12
I have the water witch and it has been working for years and never came into any situation there it refused to detect it being submerged.

Sybaris
24-10-12, 07:57
One very nice feature with the water witch and some other electronic switches is the built in delay for both on and off. I am never going back to a mechanical switch.

pcatterall
24-10-12, 10:12
Thanks guys. For simplicity to fit the existing set up I have ordered 2 'traditional' ones from Seamark. I will consider the water witch type later. I took the completly duff one to bits and there was orrible signs of water ingress presumably from the cable seal or the shaft. I dont think the switch has been submerged more than a couple of times so hardly fit for purpose?
It would be better if the float was lower than the switch so that the switch itself was kept out of the water but, clearly, this would make the device much more awkard to fit.
As stated I have checked them quite often ( hooking my toes under the switch!!) they always worked until the day I came to winterise the boat when both failed, The old sods law in action, made worse by being in mid France with no chandlers in sight!!

sailorman
24-10-12, 10:24
Thanks guys. For simplicity to fit the existing set up I have ordered 2 'traditional' ones from Seamark. I will consider the water witch type later. I took the completly duff one to bits and there was orrible signs of water ingress presumably from the cable seal or the shaft. I dont think the switch has been submerged more than a couple of times so hardly fit for purpose?
It would be better if the float was lower than the switch so that the switch itself was kept out of the water but, clearly, this would make the device much more awkard to fit.
As stated I have checked them quite often ( hooking my toes under the switch!!) they always worked until the day I came to winterise the boat when both failed, The old sods law in action, made worse by being in mid France with no chandlers in sight!!

My WW just delivered this morning, 2 days after ordering on ebay .27.48 delivered
It was supplied by Marine Scene, Porthcawl. thats very good service

nigelmercier
24-10-12, 10:28
I don't like the idea of submerged electrodes in my bilge...
I've been thinking about this. Can someone who has a Water Witch confirm if the electrodes are permanently powered? If it just does a blip every minute or so, I may change my opinion.

lw395
24-10-12, 10:33
I've been thinking about this. Can someone who has a Water Witch confirm if the electrodes are permanently powered? If it just does a blip every minute or so, I may change my opinion.

Presumably if the electrodes are submerged, it switches on, an un-submerges them?

I did experiment with a FET based switch, permanently on, but the cheap float switches came along and solved the problem before I'd tested it with rainwater, seawater, oily bilgewater, spilled coffee etc etc.

For most yachts, I maintain that it is much better to sort the leaks at source.

winsbury
24-10-12, 10:35
Has anyone tried one of these gizmos that attach to the dock line that incorporate a set off bellows that use the movement of the boat to pump water from the bilge - seems eminently sensible to me, no electrionics, no battery drain and no parts that can suffer corrosion ? They had one at the boat show on demo and it seemed to work very well.

http://www.unimer-marine.com/products/drainman-bilge-pump/

discussed breifly on this thread too: http://www.ybw.com/forums/showthread.php?t=284778

sailorman
24-10-12, 10:37
I've been thinking about this. Can someone who has a Water Witch confirm if the electrodes are permanently powered? If it just does a blip every minute or so, I may change my opinion.

http://i118.photobucket.com/albums/o88/orwellbridge/Scan0002-1.jpg

sailorman
24-10-12, 10:40
Presumably if the electrodes are submerged, it switches on, an un-submerges them?

I did experiment with a FET based switch, permanently on, but the cheap float switches came along and solved the problem before I'd tested it with rainwater, seawater, oily bilgewater, spilled coffee etc etc.

For most yachts, I maintain that it is much better to sort the leaks at source.

we have a keel stepped mast,rain water enters via the sheave box`s

lw395
24-10-12, 10:52
we have a keel stepped mast,rain water enters via the sheave box`s

That can be managed.
Many boats direct water from the mast into the shower drain.
Or you can seal the bottom of the mast and pump it out from there, or plug the mast above deck level, although this is a faff with wiring.

It's worth doing IMHO, it transformed my last boat from a damp to a dry boat.

nigelmercier
24-10-12, 11:03
rain water enters via the sheave box`s

Via the sheave box's what? :)

sailorman
24-10-12, 11:07
That can be managed.
Many boats direct water from the mast into the shower drain.
Or you can seal the bottom of the mast and pump it out from there, or plug the mast above deck level, although this is a faff with wiring.

It's worth doing IMHO, it transformed my last boat from a damp to a dry boat.

we are dry really & have a nice sump of about 15 lts unlike many "flat bottomed" boats. the switch is really a safeguard over the winter period

winsbury
24-10-12, 12:03
The problem as I see it is that all the bilge switches miss the fundamental point - they should turn on when the water reaches a certain level and turn off once its dropped to a certain level. All the arrangements with a single switch cannot do this so either keep switching on/off rapidly which rapidly wears out pump and switch, the more complex devices have a time delay which helps but may mean the pump runs longer than need be and possibly runs dry. My solution below - btw these switches are available on ebay for about 10 http://www.ebay.co.uk/itm/160804066289?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 though I dont know if they are suitable for marine environment, nevertheless any two switches appropriately spaced would do the trick. Remaining parts available for a few pennies.

sailorman
24-10-12, 12:07
The problem as I see it is that all the bilge switches miss the fundamental point - they should turn on when the water reaches a certain level and turn off once its dropped to a certain level. All the arrangements with a single switch cannot do this so either keep switching on/off rapidly which rapidly wears out pump and switch, the more complex devices have a time delay which helps but may mean the pump runs longer than need be and possibly runs dry. My solution below - btw these switches are available on ebay for about 10 http://www.ebay.co.uk/itm/160804066289?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 though I dont know if they are suitable for marine environment, nevertheless any two switches appropriately spaced would do the trick. Remaining parts available for a few pennies.

i have a Jabsco diaphragm pump in the lazerette,it can run dry.
those impeller pumps in the bilge are very unreliable

fisherman
24-10-12, 14:39
My last boat had the washing machine pressure switch arrangement, pipe down to the bilge, all connections up in the dry, very good. This boat has a switch in the bilge, don't know the make, it has a horizontal tube with a reed switch inside, a hinged tubular float below with a magnet. It has needed repair once in 20 years, but it only runs the bilge alarm, so low draw may be the reason for long life.

CreakyDecks
24-10-12, 15:15
we dont have oily bilges thank you very much :p
we do get rain water via the mast sheave box`s though :)

Read the "Note" at the end of that WW leaflet. If the rainwater is too clean it won't see it!

Graham_Wright
24-10-12, 15:24
For most yachts, I maintain that it is much better to sort the leaks at source.

Switch off the rain you mean?;)

lw395
24-10-12, 15:30
Switch off the rain you mean?;)

Park it indoors or move to a better climate?

sailorman
24-10-12, 16:58
Read the "Note" at the end of that WW leaflet. If the rainwater is too clean it won't see it!

yes noted that, its not in the advertising Blurb is it :rolleyes:

dmmbruce
24-10-12, 17:20
Read the "Note" at the end of that WW leaflet. If the rainwater is too clean it won't see it!

Yes, a disclaimer for legal reasons.

How often have you heard of bilge water, of whatever source, being as "clean" as distilled water?

;)

Mike

sailorman
24-10-12, 17:52
Yes, a disclaimer for legal reasons.

How often have you heard of bilge water, of whatever source, being as "clean" as distilled water?

;)

Mike

my previous switch of a different make ( from a very honourable forumite :cool:) did 3 yrs trouble free
years. i only knew it was u/s when i went o/b to find the pump running with dry bilges.
the WW has sensors similar to the original & that worked ok ;)

winsbury
24-10-12, 18:35
All the Whale stuff Ive used in the past has been very good so perhaps these are too:

http://www.whalepumps.com/marine/siteFiles/resources/docs/resource-library/datasheets/SupersubSmartRangeDatasheet.pdfo ...

Chalker
22-03-13, 18:28
Thanks Winsbury.
Having designed electronics for most of my working life and developed a healthy mistrust for electronics near water, i'm using your float switch and relay circuit.

winsbury
22-03-13, 18:39
Thanks Winsbury.
Having designed electronics for most of my working life and developed a healthy mistrust for electronics near water, i'm using your float switch and relay circuit.

Excellent, let me know how you get on. It would be really interesting to see a photo of your finished item in situ when its done.

captainboo
22-03-13, 18:49
The problem as I see it is that all the bilge switches miss the fundamental point - they should turn on when the water reaches a certain level and turn off once its dropped to a certain level. All the arrangements with a single switch cannot do this so either keep switching on/off rapidly which rapidly wears out pump and switch, the more complex devices have a time delay which helps but may mean the pump runs longer than need be and possibly runs dry. My solution below - btw these switches are available on ebay for about 10 http://www.ebay.co.uk/itm/160804066289?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 though I dont know if they are suitable for marine environment, nevertheless any two switches appropriately spaced would do the trick. Remaining parts available for a few pennies.

I might be wrong but is the labelling of the 'a' and 'b' switches the wrong way round in your diagram, in the first paragraph? You have labelled the lower one (turn off) as 'a'. Surely as soon as the level gets to this switch it will turn the pump on straight away before the level gets to 'b'?

winsbury
22-03-13, 18:56
I might be wrong but is the labelling of the 'a' and 'b' switches the wrong way round in your diagram, in the first paragraph? You have labelled the lower one (turn off) as 'a'. Surely as soon as the level gets to this switch it will turn the pump on straight away before the level gets to 'b'?

Ah, do I say "oops, well spotted", or do I say "it was a deliberate attempt to put anyone off that couldnt read a diagram therefore shouldnt be trusted anywhere near a soldering iron."

I think I'll go with well spotted. :)

PS: just for clarity: the diagram is correct, its only the letters 'A' and 'B' in the first paragraph which should be reversed to make the description read correctly.

The pump will switch on only once it reaches the upper switch and wont turn off again until it reaches the lower switch. So provided the vertical gap between the switches is larger than the wavelets normally found inside the bilge the system will prevent the pump overrunning (ie, wont go completely dry which is not good for impeller pumps ) and will not under-run (ie no short bursts) which can be bad for the motor and switches and is in efficient and might create unnecessary RF interference too.

Chalker
22-03-13, 19:24
I don't think that it needs a 2 pole relay either. (Not just because I bought a single pole one!).
I'll fit a 'spike' diode across the supply as well to keep it off the boat supply

surekandoo
22-03-13, 19:32
Super sub doesn't work if there is mud or silt in water! Found this out to my cost. Rang mfrs to complain but was told this was a known issue! Nothing about this in sales blurb or fitting instructions!

Caveat emptor!!!

pampas
22-03-13, 23:12
Why not make your own using a level switch from a Hoover auto washing machine?

nigelmercier
22-03-13, 23:52
Why not make your own using a level switch from a Hoover auto washing machine?
Does it have to be a Hoover?

pampas
23-03-13, 15:23
No. But the simplest to adjust as only 2 funtion screws. most others have 1/2 load level function as well and are pigs (From experience) to adjust for the low level bit.

VicMallows
23-03-13, 17:02
Why not make your own using a level switch from a Hoover auto washing machine?

What is the least depth of water you have been able to reliably detect? I'm sure it will work fine in a deep bilge, but I'd be surprised it it can detect 2 inch water depth, which is what I need in my shallow bilge.

fisherman
24-03-13, 14:00
What is the least depth of water you have been able to reliably detect? I'm sure it will work fine in a deep bilge, but I'd be surprised it it can detect 2 inch water depth, which is what I need in my shallow bilge.

Just put an inverted funnel on the bottom end of the pipe, the pressure differential is larger for shallow depths.

VicMallows
24-03-13, 18:04
Just put an inverted funnel on the bottom end of the pipe, the pressure differential is larger for shallow depths.

The funnel will increase the volume of air available to operate the switch. It will not increase the pressure. My question was whether 2 inches of water pressure is sufficient to reliably activate the washing machine switch. I was assuming that once the bilge was pumped dry, the pressure tube would be above water/open to air. If not, the differential becomes an issue and is likely to make reliable operation even more difficult.

I repeat: has anyone actually got it to work with a 2 inch bilge water depth?

pampas
25-03-13, 09:49
What is the least depth of water you have been able to reliably detect? I'm sure it will work fine in a deep bilge, but I'd be surprised it it can detect 2 inch water depth, which is what I need in my shallow bilge.
Can be set so low that the pump will run all the time. I set mine so that the pump grill is always covered and cuts in when I have 6" in the sump.

winsbury
25-03-13, 10:21
Just put an inverted funnel on the bottom end of the pipe, the pressure differential is larger for shallow depths.
I'm not sure that will work very well, the theory you are proposing is that of hydraulics as far as I can see, ie the large area of the open funnel will act as a large piston acting against the small actuator of the switch. The problem is that the air in the funnel is very compressable so the pressure increase will not be increased as much as one might hope and might not be sufficient to trigger the switch, it depends somewhat on the sensitivity of the switch of course. The same problem with pressure switches occurs when located remotely ( via an air tube ) , the longer the tube, the greater the air volume so the less effective the transfer of pressure.

It might be possible to create a lever which actuates a master cylinder to push a fluid/rod/wire to/from a remotely mounted switch but I'm not sure I see any advantage to making the system more complex mechanically.

I would have thought the only way to sensibly detect very low levels of water would be electrodes that sense depth, either simple 'water present or not sensor' or a continuous water depth sensor similar to a fuel level sensor and trigger the pump based on settings in the detector. This could be as simple as on/off or as complex as a processor controlled sensor that could incorporate hysteresis and removal of wavelets caused by the motion of the boat. With predictive programming it might even be able to pulse the pump to only work as a wavelet passes the inlet to effectively dry the bilge slightly below the level of the inlet.

A wise man once told me to get to the other side of a long high wall one could build a brick diminishing vacuum generator with reconstitution engine that would vapourise the bricks and then replace them after one passed through to the other side safely. Alternatively, one could use a ladder.... the moral is that we are in danger of over engineering a response to simple problem.

fisherman
25-03-13, 17:16
I had a pipe/pressure switch bilge alarm for years, it was very effective. The simplest bilge alarm/switch I've seen was a straight wire passing through staples or some such attached to a bulkhead, float on the bottom end, switch at the top. The stainless wire inside a morse 33c cable is very useful for this, and other random purposes.