Posted 2/9/2010 07:24 (#1065540 - in reply to #1065490) Subject: Re: Raven Accu-Flow NH3 system - single valve or 2 valve?
Ron explains the differences pretty well. I bought a used single valve a few years back...it works fine and has been trouble free. For your 440 to work with single valve, it has to be new enough that it has a serial port on the back. That is your clue to whether it has the firmware to run fast valve or not. You can send an older unit to be updated, but it's not cheap.
Raven Accu-Flow NH3 system - single valve or 2 valve?
