Re: Diagnose roof top a/c units
The most common place for an air conditioning system to leak, is the seals on the back of the compressor. If it's an R-134 system, I'd drain it out, disconnect the two lines on the compressor, swap those seals real quick like, reconnect the lines and service it back up. If it's R12, you might even be able to convert it to R-134. I don't know. You'd just need an accumulator drier. Anyways, if you can swap the lines pretty quick, there's no need to put a vacuum on the system.