1. 13,500. They don't make a 12,500
2. What good are the gauges??????? RV AC units have NO service ports. Since you are a novice, I would advise against trying to tap into and install clamp on ports. Clamp on ports are good for one thing---making money for qualified service people because they all leak eventually from the compression of the copper tubing. You always solder in fill ports after draining the system with clamp on taps.
3. The ONLY way to test an RV AC is by temp corrected compressor amp draw. Which you can do by buying an inexpensive clamp on AC amp meter. Doug
