Went to take a look at a reach in cooler. I believe it was a Randell made in 1985. The unit was cutting out on overload. The tech before me replaced the compressor. Any way the inside temperature was around 60 degrres. I hooked up my gauges and got pressures of 30/200. The unit was in a kitchen and the ambient was 103 degrees. I know with that low suction pressure and high SH, I had a restriction. I guessed that the refrigerant used was R409a because when I shut the unit off the pressure settled down to 150-155 on the liquid side. The suction did not get much higher than 50psi. I think that the subcooling was around 9-10 degrees. Anyway I was wondering if there is any reason they stuck with R409a when they replaced the compressor rather than go with R134a?