"user" wrote in message
...
Thanks..

Well, he did suggest that it might be a leak, but he first suggested that
we should wait for it to blow cool air, and then if it doesn't, then call
him out again for a leak search..

Is there any way to tell that the leak is coming from the machinery in
the attic above, or from the actual unit outside, (where the fan is)

Thanks

Yes, the tech should use a leak detector.

Anything mechanical will wear out and break. Leaks happen from seals drying
out, mechanical loosening from vibration, joints getting bumped into, etc.
While it can take some time to find the leak, he should have at least made a
quick check of the obvious easy to reach places as a start.