EBiab single vessel questions

[Vallan]

I'm slowly finishing acquiring my parts for what will be come an electric single vessel biab build.

Im using an 80 qt concord kettle

5500W SS 240V element

Chugger pump that will pump to top of lid where there will be a T with a temp probe, and through the lid into a mash recirculation kit

Got a great BIAB bag from Wilserbrewer

Just waiting on PID & timer from Aubrins and then putting it all together.

So my questions are:
Basket/false bottom - I don't have a basket or false bottom. I read many concerns about pump cavitation allowing the element to scorch the wort. I will restrict the output flow from the pump but I'm wondering what others doing single vessel suggest. I'd considered a smaller basket with standoffs on the bottom thinking somehow the gap on the side would help if it was filling top of basket faster than it could drain back out. I saw someone used what looked like a round grate from a grill to keep bag off the heating element. Not sure what way to go here.

20 gal pot (19x19x20) - Any idea what my min brew size could be? I assume I can still do 5 gal batches but 3 gal prob not?

240V/120V combo - Given 1 of the 2 120V hot legs power runs everything but the 240 element, could you add 2 breakers (1 for each hot leg) could you trip the 1 120VAC breaker (call it L2) that wasn't supplying 120V to the box and assuming you had a plug adapter run your box and 240V element at 1/4 the wattage?
I'm also considering adding a 2nd SSR and 120V socket so I could put an element in a smaller 5 gal pot and use the same control box so it would be easy to do some 3 gal batches as test runs.

Thanks for any advice!

 

[doug293cz]

To run the heater either at 240 or 120, you have to add a SPDT contactor that switches one of the heater inputs between one of the hot legs (the one not controlled by the SSR) and neutral.

Brew on

 

[jeffmeh]

To run the heater either at 240 or 120, you have to add a SPDT contactor that switches one of the heater inputs between one of the hot legs (the one not controlled by the SSR) and neutral.

Brew on

And it would be best to have a 3 way switch that goes through off when switching between the 240v hot and the 120v neutral.

 

[wilserbrewer]

While I have heard of someone running a similar system without a false bottom or basket, I would think you want separation between the grain / bag and the element to avoid scorching. This could be a F/B, basket, or a guard of sorts over the element. Thinking a piece of perforated sheet, aluminum or stainless punched w/ large holes bent to cover the element? Nothing fancy, perhaps a piece of aluminum flashing?

 

[cyberbackpacker]

As for batch size, 3G will definitely be out, and you'll need to make sure your element is not higher than 4 inches from the bottom of the kettle to do five gallons.

 

[BeeRRunBrewery]

To keep the bag away from the heating element we use a round stainless cookie sheet with legs. Works great. But yes, you'll want to play with the valve output so not to recirc more than the bag lets through.

 

[doug293cz]

To keep the bag away from the heating element we use a round stainless cookie sheet with legs. Works great. But yes, you'll want to play with the valve output so not to recirc more than the bag lets through.

And make sure you throttle the flow with a valve on the pump outlet, NOT the kettle drain valve. Otherwise you risk pump impeller cavitation, which will damage the pump.

Brew on