Buying used C.A.P. Controllers

Hello, i'm thinking about buying a used CAP controller and since i'm unfamiliar with this type of equipment i was wondering if anyone could tell me if these controllers are really delicate and maybe a used one is not a good idea or if they are really sturdy and reliable and it is usually okay to buy used ones. i'm looking at a CAP Air 3 controller which controls temp/hum and CO2 with a photo cell, it's less than a year old. thanks.

MG

I haven't look at them. But if its UL/CSA listed its fine.

I rolled my own controller (though I do industrial controls for a living)
Having CO2, Lights, watering, and vent fan from one controller is a nice perk. (mine is 4 zone)

Multiple controllers can fight each other. Don't want the CO2 to fire is the lights or vent is on. etc.