BIAB build help

What I have done is I put 2 3kw elements in a 13 gal pot. I was wondering if I should have a switch to change to 110v on elements during mashing. Now I have food grade pump twice the size of the regular chugger pumps to cycle wort through chiller and back into pot until it reaches desired temp before pumping into fermenters. While I'm mashing the pump is too large to control to circulate wort back over mash. What would be a good quality pump to do this circulation? I'm trying to cover everthing I will need on controller before build. I'm building this to be all on one stand that can roll around. It will have 2 13 gal fermenters, 13gal boil pot, refrigerator unit to help with wort chiller and for circulating cold glycol for fermenters. Any input would greatly be appreciated.
Thanks

 

A couple questions...

1. Why two 3k elements? Why not a silgle 4500 or 5500?
2. Have you tried putting a ball valve on the output of the pump to control flow. Should be a much cheaper option than trying to run two different pumps. More simple as well.
3. 13 gal fermenters are great but do not expect to fill them with a 13 gal setup. At least not without multiple runs. I can get 10 gals of wort out of my 15 gal system as long it is not high gravity.

As for a controller. I use a high gravity brewing suply panel http://www.highgravitybrew.com/store/pc/EBC-SV-120V-with-Infinite-Power-Control-306p4648.htm If building a panel there are many tutorials on this site.

 

I could choke the pump but wondered if that would limit life of pump since it is larger than normal chugger. I was going to build controller around auber 2362 and timer to be used for different functions. And what about turning elements to 110v during mashing? I'm just trying to build this as compact and self contain as possible.

 

You could probably use your existing pump with a bypass line. In other words, you only direct a smaller portion of the flow to the pot, and the rest goes back to the pump. This would require some plumbing and valves but would prevent the additional of a second pump.

 

Pumps are designed to throttle their discharge. One of the largest pumps I've specd is a 7500 gpm propane pump. We throttle those pumps all the way down to about 700 gpm during some points of operation. If you don't throttle and there's not enough pressure drop induced by the system, which can be likely in a homebrew set up, the pump will run out on its curve and that can cause problems too, such as insufficient NPSHa.

But don't dead head the pump either. Every pump has a MCSF (minimum continuous stable flow). Just stay above that and you'll be fine.

Hope this helps.