Float valve water sensor?

[robwok]

I built 2 gray water tanks to fit in my 64 Overlander. I kept hearing about the terrible reviews on tank monitors, and decided I didn't want to deal with it. However, I'm looking at a camp site that offers electric and water, but a dump station. Now, I don't know when the gray tanks are full until they are over loaded.

My thought is this: I have the 2 tanks side by side, and they both have vent pipes coming out the top, tying into the kitchen vent pipe. I had to drop them once, so I cut the pipe and have the rubber fittings on them. No big deal. What I'm thinking about is using an aquarium float sensor. Drop it down into the vent pipe, then drill a tiny hole for the wires to come out and then seal that. Hook that up to my 12v system, and basically, when the float comes up, it just turns on a 12v LED to let me know my tanks are full. I won't get a gradiated system, but I could set it when they are 75% full.

Any thoughts? It would cost me about $15 for the whole deal.

Rob

[AnnArborBob]

I'm no expert, but since you asked...

My principal concern with your proposed approach would be the durability of the float valve mechanism during towing when it would be subject to either sloshing around (if the tank was near full) or other torque forces if left hanging in an empty tank. Perhaps your design has taken this into account?

Our 2014 Eddie Bauer uses sensors that are mounted outside the tank (rather than the three contact points inside the tank) and they seem to work quite well (so far!) The idea with these particular sensors is to keep them out of the tank so they don't get fouled.

[dbj216]

I'm really happy with my Garnet SeeLevel sensors. They are mounted to the exterior of the tanks and use inductive capacitance (I think) to monitor the tank level. The system was about $250 to install on my 66 Trade Wind. But so far it has worked very well. A thumbs up from me.

David

[robwok]

One issue I have is that I used 1/4" black abs for my tanks. That's not the same as 1/8" semitransparent polyethelene (or whatever the thickness is). Additionally, the sea level sensors cannot be cut any shorter than 4.5" Since my overall height is only 4", I'd have to hang the sensor below my belly pan, cut a slot in my floor, or put it on at a 45 degree angle. So, I think the see level would only work on my black tank- which is almost 6" deep and relatively large, and I can see through the top. The black ABS was also great because it is somewhat structural, so I could use several wide straps and not a full length plate to support it all the way across the bottom of the pan. I could weld any fittings to it, repair it easily, etc.

So, I'm going back to my original. I found a stainless steel float sensor that actually had 2 sensors in it, one always on, one always off. I can take off the lower censor, and drop it down within my vent pipe. This can run a 12v LED light to warn me when I'm at 75%. If I wanted, since I have 2 vent pipes, I could put one in each at different levels. That means I could basically have a 50% and 95% lights come on for only about $25.00 Being able to monitor my tanks for $25 vs $250, for something I can't even use seems like a good deal to me. The stainless steel ones have really good reviews vs the plastic ones. It would also be something I could replace in less than an hour's time from the inside of the trailer under the twin bed vs dropping the belly pan for the other sensor types. I realize this isn't the best option for new trailers with tanks that can use see level, but for shallow tanks, seems like a great option.

[AnnArborBob]

Sounds like you've landed on a sensible solution given all your variables. I would just encourage you to do the obvious which is to protect the sensors as best you can from getting banged around so much that they fail. I'd be especially concerned about the black tank sensor since it will have some solids sloshing around in there.

[robwok]

Yeah, I don't plan on using with the black tank. That one gets the flashlight method. I also installed tank washers on all the tanks , so that should help keep them clean.

[AnnArborBob]

Originally Posted by robwok

Yeah, I don't plan on using with the black tank. That one gets the flashlight method. I also installed tank washers on all the tanks , so that should help keep them clean.

The "flashlight test" for the black tank is still be best and most foolproof method!

By "tank washer" do you mean a head similar to the back tank flush? Did you put these into both your grey tank and the fresh water tank?

I usually flush the grey tank by filling up the kitchen sink after I've dumped the grey tank and then pulling the plug. It is amazing what comes out of the grey tank when it is flushed! Never thought of flushing the fresh water tank, just use the chlorine approach periodically.

[robwok]

no, the tank washers are these: Amazon.com: Camco 40123 Quickie Flush with Back Flow Preventer: Automotive
They are inserted into the gray and black tanks. For me, I'll go to the dump station. I have one Valtera hookup, with 2 valves. I only hook the hose up once. I pull the black tank valve, then I pull the gray tank valve. Then, I hook the hose up to the tank washer line. That shoots water to a tank washer in each of the gray tanks, and 2 of them in the black tank. So, all 3 of my tanks get rinsed out, and I stay in the same spot at the back of the trailer. I don't need to go inside, and the tanks get rinsed by these spinning rinsers. I did change mine out to be all pex, as I didn't trust that soft clear hose - and I wasn't going to be able to see it anyway.

I thought about this whole process a year. I just need to blow air through this and the rest of my lines before winter.

Rob

[dbj216]

Hi robwok, Your tank configuration in both thickness and height discounts the see level sensors. Your idea of a durable float switch seems good for these "pancake" tanks.

David

[robwok]

I updated my main thread with pics of the tank sensor. you can see how I did it here:
http://www.airforums.com/forums/f157...ml#post1577719