Sure, it's in the User Guide. Self-Healing (power and channel adjustments) begins on page 116.
https://support.ruckuswireless.com/documents/842-zonedirector-9-12-1-user-guide
From your ZD's Configure->Services page, Self Healing is the top section. Background Scanning
is the default channel test/selection method, and uses only channels 1/6/11 in 2.4G. If you select
Channelfly, your AP will initially go off channel more frequently to build a table of interference seen
on all 11 of the 2.4G channels, but will eventually select the best choice from 1 to 11. (should provide
~33% better overall throughput) In environments with clients sensitive to channel changes, we advise
to disable channelfly after a few hours to a couple days, when APs have settled on best channels,
leaving them statically assigned to their last channel.
The section below Self-Healing is Background Scanning interval, with a default 20s for APs to look
at the other channels and report in to the ZoneDirector. If using Background Scanning (instead of
Channelfly as your Self-Healing method), the ZD will tell APs to change channels (and/or power)
at regular 600s/10min intervals, if needed.