I was thinking of setting up a grant with a float switch and was wondering the same thing. What we want is hysteresis, like a thermostat. Do any of the float switches have this?
-Eric

Nope not that I can tell.

Seems to me you could change your SSR hookup on the control side and add hysteresis with an R/C.

I think you could ground one side of the SSR, tie the other to your 12V rail with an R, and put a big C across the SSR. Your float switch would from the C anode to ground. This assumes the switch closes at "liquid high" position to shut off the SSR. When the liquid level is dropping and the switch opens, the C would charge through the R up to the on threshold of the SSR. The time is determined by the values you use for R and C.

If the SSR input is really sensitive (I don't know if it is or not), you could do it with a transistor thrown in there with the R/C, but you probably know that already.

I'm happy to draw it up if someone wants to try it.

is it possible to use the float switch with a asco type valve to control wort flow? I would like to use it with my hop back, the level of my hop back is below my boil pot so the wort bleeds back from the pump and turning off the pump will not work.

Our grant at work has a two part float switch. Two floats, the first near the bottom of the grant doesn't activate anything at first. Once the top float switch is activated, the pump runs until the bottom switch falls. I don't know if this is available in a shorter size, since a homebrew grant would probably only be around 2-4 quarts and perhaps 8-12 inches deep. I would definitely think that some manufacturer makes a float switch like this that is shorter, the question is how reasonable is the cost.

Maybe you could set up two separate float switches in the same vessel?

That's what I do on a homebrew scale. I use the B3 dual float switch for my sparge to keep the mash level between the floats and then flip the float sliders around for the grant and hop back to do the same.

I'm just designed a system like this for my new setup. It seems there are a lot of potential reasons to add in float switches at some point. Thinking about putting 4 or 5 MONO head phone jacks in the line, which i can than plug in floats as necessary. in the unused ones just plug in a little jumper to complete the circuit. I see the need for setting a high point and low point for the pump to go on and off, but in the end, without a delay of some sort it seems that one of these will always be the trigger for the pump, and it will go on and off a lot. A big part of the reason for doing this is being able to set it and forget it, but if you are not constantly monitoring the output and input, it could just keep hitting that high mark, shut off, hit the mark shut off and work the pump really hard. with two floats, unless you set the input exactly as the output, it will always rest at the height of one of the floats. The only way i can see around this is by having some sort of delay. If someone has time to draw up how to run a R/C delay that would be great. I suppose so that you have a high mark, when it hits that, it shuts down for a short time, unless it hits the low mark, in which case it turns itself back on, or the capacitor kicks in and turns it on. I'm still trying to get back into the basic electronics of my youth so please be as descriptive as possible. Thanks!

scott

it is definitely possible, you would have to run the float valve through a 12v Relay coil and run the asco line through the contact point, basically the exact same set up as for the pump control, except you plug the asco in, assuming its 110v.

I'm doing something like for my wort heater/chiller. Using one coil and a 3way asco, the pump will pump the wort through the grain bed constantly, and depending on the temp of the wort (set on a RANCO ETC) it will either direct the wort through the heat coil or a bypass back into the mash tun. Then, after final boil, i fill the HLT with cold water/ice and run the hot wort through the coil, set the temp to my pitching temperature and recycle the wort through until it cools, then just pump out to fermentation. It basically creates a hybrid counterflow, cold water passes through the HLT and out the drain while the hot wort is run through the coil. once the temp is down a bit (140deg or so) i throw in ice and it chills very quickly. In the winter with cold house water the ice isn't really necessary, just faster. I suppose you could go a step further and get some glycol or AC unit to chill it, but this seems to work.

In any case, yes, you can hook the valve up to the float, not a bad. I may do that for sparge and drain to fermenation.