Have a klimaire 24,000btu in the server room for about 6 months now. Zero problems until today. The unit was not cooling properly today and the room temp was rising. I noticed the 2 coils that come into the building were freezing, had ice on them. The outside coils however seem fine, with no frost. I poped the face plate off on the indoor unit and there was also some ice on the lower portion behind the filter. I shut everything down for about 45 minutes and it all melted. Fired it back up and it is running fine for the past 30 min or so. The inside lines seem awfully cold though. The outdoor temperature here is currently 15 degrees. I have had zero issues with low outdoors temps screwing things up. I had a head pressure controller installed on the unit. The head pressure controller on the unit has "setpoint" that you can set anywhere from 30 degrees C to 60 degrees c...what should I have it set at? Does this have anything to do with it?