How fast should a rims pump go?

Im in the process of designing a rims and couldnt find anything on the speed that the pump should be going at(gph). Any rims guys have a rule of thumb?

"42"?

Whatever the magic number is, consider most of us here use March 809/815 or Chuggers, and on their best day they're moving ~8 gpm - which you can bet gets throttled back pretty stiffly to keep from sucking the entire grain bed into a humongous impermeable knot. So unless you're working with out-of-norm scale figure 8 gpm is a good place to start...

Cheers!

[edit] I meant pump sizing, of course. A ball valve on the output will control actual flow rates as necessary...

I would count on 1gpm or less to start. I try to set mine to a trickle without actually setting out to measure the rate of flow. I figure that probably equates to about .5 gpm.

I run mine full throttle with a March 809, probably close to 8gpm like day_trippr said.

Thank ya. Knew to use a ball valve to slow the speed but just wasnt sure if i should have it pumping at normal lauter (basic igloo all grain set up) speed or what.

My US Solar pump (3 Gal/min?) is fine for RIMS, throttled back to about 0.5 - 1 Gal/min. As long as you have enough flow to prevent the element scorching the wort, it's OK, during mash rests.

If you want to do a stepped mash or mash out step, then you'll want to run the pump as fast as you can without getting a stuck mash (or at least as fast as is required to keep the element on 100% while under PID control), as this will let you heat the mash as fast as your element's power output allows. With a domed false bottom in a 10gal round cooler, I can open up my pump all the way for normal mashes.

So .75 gal a minute would be no good for step mashing?

I have always run mine as fast as possible, especially when step mashing. Adding some rice hulls pays off too.

I run mine at about 2/3 of wide open. That is probably about 3-4 gpm. That seems to be about optimum to add just a little heat to maintain temp. I've never had any scorching at that setting.