Pressure-operated Bilge switches

[Nord Sal]

Does anyone have any experience with the pressure operated bildge switches like those offered by Jabsco or Groco? I'm hoping I can find something that works and lasts. The units which rely on the liquid's conductivity sound like they foul if there's oil in the bildge. These have nothing electrical submerged and I like the sound of that.

I tried the search function and found a little but info, but didn't see any comments about these.

These are the two models I'm looking at:

https://www.xylem.com/en-us/products...dro-air-switch
https://www.groco.net/products/pumps...0-bilge-switch

[transmitterdan]

Originally Posted by Nord Sal

Does anyone have any experience with the pressure operated bildge switches like those offered by Jabsco or Groco? I'm hoping I can find something that works and lasts. The units which rely on the liquid's conductivity sound like they foul if there's oil in the bildge. These have nothing electrical submerged and I like the sound of that.

I tried the search function and found a little but info, but didn't see any comments about these.

These are the two models I'm looking at:

https://www.xylem.com/en-us/products...dro-air-switch
https://www.groco.net/products/pumps...0-bilge-switch

I have tried the Jabsco and it works but is a bit finicky. The problem with these is the tiny amount of pressure required to activate them. Typically they use 1 PSI or less to activate. That makes them prone to sticking in the on position.

I much prefer the Aqualarm Heavy Duty model 20090 switch. It avoids all the things you are right to worry about. Does not have any electrical parts in the water unless your pump fails. Even then the electric parts are well sealed. And it is very accurate and unlikely to stick in the on position. Even flotsam in the bilge will not hang it up.

[Nord Sal]

Thank you for the reply. I wondered about the actual electrical switch mechanism above water. Both of these switches operate on a pressure differential of about 1.5 inches of water. One foot of saltwater (12") is about 0.44 psi so the mechanical side must pretty precise (delicate?) in order operate at the .05 psi range (1.5").


I'll look at the aquaalarm. I didn't understand the part about not having electrical parts in the water "unless your pump fails." Could you clarify that?

[slug]

I’ve been using the jabsco type for many years

No problems
Before the prepackaged units were common , washing machine level switch’s and a relay were used

Much cheaper

[transmitterdan]

Originally Posted by Nord Sal

Thank you for the reply. I wondered about the actual electrical switch mechanism above water. Both of these switches operate on a pressure differential of about 1.5 inches of water. One foot of saltwater (12") is about 0.44 psi so the mechanical side must pretty precise (delicate?) in order operate at the .05 psi range (1.5").


I'll look at the aquaalarm. I didn't understand the part about not having electrical parts in the water "unless your pump fails." Could you clarify that?

Aqualarm heavy duty switch uses a float and a vertical rod with the electrical switch above. So as water rises the float pushes the rod and activates the switch. The switch and wiring is always above the water line. That is unless the pump fails to run. But even then the switch is sealed so it won’t get wet.

The float is protected from gunk because it is inside a plastic housing with small holes that act as a filter to let water in and out. So it will not jam up even if the bilge is full of trash. That doesn’t help the pump but at least the float switch will not get jammed.

[tkeithlu]

The most common recommendation when I asked about alternatives to float switches was the Water Witch, at about $40. It's electronic, and won't trigger in oil/fuel, but will when the oil film gets above it. I'm using one now, and plan to buy others as I get fed up with bilge pumps that stick in the on position.

[Ben51]

Originally Posted by transmitterdan

Aqualarm heavy.........

The float is protected from gunk because it is inside a plastic housing with small holes that act as a filter to let water in and out. So it will not jam up even if the bilge is full of trash. That doesn’t help the pump but at least the float switch will not get jammed.

I have the Aqualarm on two different boats. Both tend to stick on. I agree it is not trash doing this. I originally thought oil in the bilge was to culprit, but one boat has outboards, so no oil and on the other boat I have now clean the bilge spotless-So no oil.
Cannot figure out why they stick on?
Anyone have any ideas?

[transmitterdan]

Originally Posted by Ben51

I have the Aqualarm on two different boats. Both tend to stick on. I agree it is not trash doing this. I originally thought oil in the bilge was to culprit, but one boat has outboards, so no oil and on the other boat I have now clean the bilge spotless-So no oil.
Cannot figure out why they stick on?
Anyone have any ideas?

No but check the installation. I believe these switches should always be mounted as close to perfectly vertical as possible. On a sail boat there will be times when heeled the switch is not exactly vertical. In that case I think the mechanism might stick but it has never happened to me.

[Nord Sal]

Originally Posted by slug

. . . Before the prepackaged units were common , washing machine level switch’s and a relay were used

Much cheaper

Thanks to all who've responded. I appreciate the real-world experiences.

I'm curious about the level switches for washing machines. I presume these are adjustable since all washing machines that I've seen operate with about 12 - 18" of water depth. How can these be made to operate on just, say, 2 or 3 inches of fluid?

[Tsuru]

After a couple disappointments I settled on an Ultra Junior from Ultra Safety Systems (high differential). Not cheap but flawless operation for years of use.
https://www.tefgel.com/#

[a64pilot]

I have had very good luck with Ultra switches as well. They are not pressure operated, but use a magnetic reed switch, Reed switches are sealed similar to light bulbs, so they are very sealed, and often they operate billions of cycles between failures.
They are of course a float inside of a plastic tube with smallish holes so trash etc doesn’t affect them.
It’s not difficult to disassemble to clean them I believe, but I’ve never had to disassemble one myself
https://en.wikipedia.org/wiki/Reed_switch

[nhschneider]

A friend of mine bought one of the Ultra bilge pump float switches many years ago when they were still sold with a lifetime warranty. When the switch failed after about 20 years, he called the company and inquired about filling a warranty claim. The owner of the company yelled at him and refused to honor the warranty. Now the Ultra switches come with a 5-year warranty. Regardless, I have two Ultra switches on my boat, both about 20 years old and they continue to work perfectly. The poor customer service skills of the company’s owner notwithstanding, the Ultra switch is the only one I’d ever use.

Fair winds and calm seas.

[tkeithlu]

Hmmm. OK, every mechanical switch has a way to fail. Broad statement, but as the screen/filter gets finer it also has a greater chance of clogging, and sand can get through in any case. Pivots and rods in cases can stick.

There are two problems here. A mechanical switch can stick in the open or the closed position. If in the open position, water accumulates, potentially sinking the boat. If it sticks in the on position, it can kill the battery and then allow water to accumulate and potentially sink the boat. In either case you don't have a bilge pump. I've had both cases; I've got one right now in that my engine room pump is not coming on as small amounts of rain water come down the ventilation. I damned near sank our small open boat a few weeks ago when the pump stuck on, and rain filled the boat after the battery went dead.

Electronic switches must have ways of sticking, but they are not mechanical. The water Witch won't operate if we fill the engine room with oil, and we did that once by failing to open the fuel return from our main diesel. It popped a hose and put about 100 gallons of diesel in the bilge. That didn't endanger the boat, because the oil just moved from the tanks in the engine room to the engine room itself, but it was one honking big mess to clean up.

Overall, I'm going with electronic (water witch), plus a spare float switch tied to a high water alarm.

[Bycrick]

I’ll add kudos for the Ultra switch. I put one on my first boat, and it still worked 20 years later when I sold the boat. The new boat had two of them that were at least 10 years old when I bought the boat. After another 18 years, one of them appeared to be sticking in the ON position. They’re so difficult to access, that I bought a new one. When I got the old one out of the bilge, I discovered a sliver of wood had stuck through one of the holes which could jam the float. I replaced it on general principles, but the other switch has been there 30+ years without a problem.

[GafferMate]

Three years ago, on a forum comparing Water Witch and Ultras as superior float switches, I installed an Ultra Junior. Amazingly expensive but great until suddenly it stopped working...inspection showed this:

(https://www.cruisersforum.com/forums...ture32316.html in case I didn't do this right)



After contacting the manufacturer whose first response was to call me a murderer, he then confirmed that it was killed by a chemical not normally found in bilges and thus not covered by warranty. Obviously, only diesel or possibly gasoline and/or kerosene are the only contaminants considered normal aboard boats.



To those who also have paints and thinners stored in cockpit lockers that have a small drain hole in the floor directly over the engine room bilge, take a rueful warning from me to be sure they can't tip over accidentally (manslaughter, not murder).



Of interest was the bilge pump itself, a Rule, that was not affected in any way by whatever destroyed the float and also removed the epoxy paint in the bilge sump.



What I'd like help with now is some feedback on the Water Witch, which I haven't been able to find in Search, yet. The website for it confuses me as to how it is installed (but I can contact them)...it's comments from those who have used them that I'd appreciate.


Thanks in advance!