Old lady's system next door apparently still has her system charged with nitrogen.psig's on both sides equeal at 150 with system running.First thought was bad valves until I found system was full of nitrogen.Does anyone know if a compressor with cap tupe metering device will condense nitrogen enough to get low and high pressure readings?I don't want to waste the effort if her valves are shot.Doin it for free, so any help is appreciated.