There is an option to switch which hardware acts as primary, however, it always seems to be greyed out (i.e. not available). Is this because of my login credentials? What sort of an account do you need to use this feature?
One CI840 is connected to one CI854 only. So if that CI854 is primary, the all CI840s connecting to it will act as primary. For redundancy test, you just need to switch primary of the CI854. Please remember that all CI840s will be switched.