I use a 5500 watt RIMS to heat the strike, maintain the mash and heat sparge water as required, all at 240V under the control of a BCS-460.
Check out the thread http://www.homebrewtalk.com/f51/rims-build-129646/
. It was the basis for my build.
My process is:
RIMS temperature is monitored and controlled by probe at RIMS outlet.
1) Fill mash tun with required strike volume of cold water.
2) Heat with RIMS unit and circulate at maximum flow rate.
3) Monitor mash tun output for strike temperature.
5) When mash temperature is reached, stabilize system for 10 minutes, and hold RIMS output at strike temperature.
6) Stop system for dough in.
7) Mash with RIMS set at mash temperature with flow rate at reduced volume.
8) Mash out by raising RIMS temperature to 170 until mash tun output is at 168 and mash out for 10 minutes.
9) Start sparge with feed water supply through RIMS unit at about 1 qt. per minute, raising water temperature to 170 by the RIMS only.
Process works fine for me and I don't need an HLT in the system. A simple plumbing change would allow me to put an HLT into the system, but I haven't yet wanted to.