@biodom: Thanks very much for the clue about the drop-down selection box for the SP20 firmware version. I didn't notice the "down arrow" and assumed there was only one. I see several other TEST versions now.
@zvi: Thanks for elaborating on the 2.6.7 and 2.6.14 versions of the firmware. I's really nice to have that kind of insight. I also appreciate that Spndoolies has a a true technical guy on here from time to time, and not strictly a "corporate mouthpiece" to dispense the company line.
While I only have about 10 hours on the 2.6.14 firmware it's vastly more useful than 2.6.1. I haven't been able to coax the fan below 10 yet, even when using auto, I think I'll be able to make good progress with this.
Thanks again folks, and Spondoolies!
Thanks!
10% might be the minimum that it will work.
To try to set it to lower value: ssh to the unit, "vi /etc/mg_custom_mode", change the fan to setting to "5" for example. If you set it to "0" it will become "auto", which starts about 60 and then goes down if system is cold.
Might work, but I never set it to lower then 10%.