Hello, we have two Liebert 3000 Challengers, but about a week and a half ago one had its coils (correct term?) freeze solid. We had to shut it down and thaw it out. It has happened several times since then. We called our local HVAC company and they took a look at it, but they're not experienced with such systems and couldn't find a solution.
We're looking for advice to tell our HVAC guys on how to resolve this issue or a referral for someone in the Northern Michigan area that is certified to work on this.
Why would one start freezing up like this?