I had a HCA2200 and they are biased for (I think) ~20-25 watts of class A, which makes them run very hot - even at idle. If it's not too hot to touch I suspect yours is running exactly as it's suppose to.
Parasound HCA-2200II Runs Very Hot
I just acquired this unit through our local Craigslist. Unit is almost pristine cosmetically. The sound too, was exceptional. I found it to be better than the McCormack DNA-1 Deluxe it replaced. I am not kidding! Listening at low volume levels was quite revealing as the lows and the highs were quite apparent. I had not heard the highs and the lows on the DNA-1 Deluxe at low listening levels. Anyway, back to my point, the HCA-2200II runs very very hot when it is played for long periods of time - like for a few hours. Would like to know from others who own or have owned it if they are aware of this heat issue. It drives a pair of B&W Nautilus 802 speakers.