I have the Lennox XP-16 which has demand defrost. Last night the o/d temp was around 26 deg. The system seemed to go into defrost every 34 minutes exactly. It only stayed in defrost mode about 3 minutes each time. Since it seemed like an abnormal amount of defrost cycles, I looked outside at my unit during one of the cycles. There was no frost on the coils and only a little dripping on the ground. I did notice that the cars and lawn had a coating of frost, so it was damp out.
I this normal operation? I thought that with the demand system, the defrost cycle would be more sporadic as opposed to an exact timeframe between each and every cycle.