Float switch for a grant pump?

[Glen-Echo]

Hello, I like to use a grant attached to an upside down bottom drain Keggle MLT for several reasons -
What I don't like is that I am constantly hovering over it
and manually shutting my March pump off and on.
Looking into installing a cheap liquid sensor or float switch.
Something that will turn the pump on when the level is high, Turn the pump off when the level is low.
I would like to see what others are using - How it is wired up -
I did a few searches but did not find anything with a simple solution.
Any recommendations?

Vic

 

[sandyeggoxj]

What about one of these firing a relay? Also, are you throttling the flow of your march pump with a ball-valve on the output?

http://www.ebrewsupply.com/shop/mor...ngs/1-2-npt-stainless-steel-float-switch.html

 

[Glen-Echo]

Yes that is the idea - Would I need two? One for off/ one for on?
I do throttle the pump back usually at a constant rate - however the mash runoff speed changes (I batch sparge)

 

[sandyeggoxj]

Nope, just the one. Basically once the wort level is high enough to push up the floating part it will engage the pump to actively move the runnings to the kettle. If your runoff rate slows and the liquid level starts getting low int he grant the switch will "open" and the pump will shut off. They sell a plastic switch too for a lot cheaper. You just need a small hole in the grant and then you can attach the float switch with a weldless clamp/oring method.

 

[Glen-Echo]

Awesome - Would this wire up into an SSR?

 

[sandyeggoxj]

Do you have any sort of control system right now? PID/BCS/PLC type controls?

 

[Glen-Echo]

I have a PID - K Type - I use this to control my KType Thermocouples and heating element.

 

[sandyeggoxj]

It looks like you could run 5v through this and use that as a signal for the SSR to fire the pump. I haven't used this float switch, but that is what I see. You should be able to add it to the panel you have now. A pump will not add much heat to a SSR and you probably don't even need a heatsink for it.

 

[Chrisl77]

I use one of these float switches for my elements so I don't dry fire them. Cant beat the price and I have had them for over a year with no problems. Like sandyeggoxj said get a 25 amp ssr and wire the positive side of a dc wall charger with any voltage under 100vdc going through the float switch then the ssr. then wire the hot side of the pump through the ac side of the ssr.

 

[Glen-Echo]

Thanks for everyone's help - This is definitely my next project.