So we've finally got into A/C season up here in CT, and this weekend I run across condensing unit (2 ton?) that the HO says the compressor was changed out 2 yrs ago (not our company), but now, there is no cooling. A guage hookup revealed a dead flat charge....actually a little negative (vacuum) reading on the low side guage!!
So I dump in what I got in the truck for R22, maybe 3# worth. The unit responds well, but high side is close to 300 psi and low side is only 35 psi, so I stop. Superheat, probably 50 degrees, I didn't bother measuring since I didn't have anymore R22 and the head pressure was way too high. Plus, it's a holiday weekend and this HO always calls afterhours/weekends for service. Another tech is going back today, but says those readings are sure to mean a bad compressor....I say, more like the system has air or whatever in it besides R22, driving the high side to 300 psi and still being low on charge.
So what is it? I say compressor is fine, since it can make high head pressure and is steady. Low side is steady too, just too low. Maybe replacement compressor is wrong size if all else is copasetic? Advice?