Thanks so far... I believe the pressures are good as they checked them when it was converted a month ago. They vacuumed out the system are recharged it. I will check for the heat exchange. My concern was that the compressor will not stay engaged but once it gets to the point that the fans will stay on it seems to stay engaged. I do not know if it makes a difference but there is an audible clicking from the relay compartment every time the ac turns on or off.