one of the other techs in our office came across this on a dx chiller, scroll compressors, remote condensor 3 stories above, Sporlan OROA head pressure controller, r22.
the discharge line is at a lower pressure than the liquid line pressure. i am not talking about 1-2 psig lower either...like 20-25 psig lower. i do not know all of the details for sure, but his is a pretty good tech and would have waited for pressures to settle out before questioning it. he checked it after it was running (the unit runs 24/7/365) for a while. he checked on 2 different gage ports on the discharge line and 2 different ports on the liquid line. it was warm enough outside to use 100% liquid line, but i do not know for sure if the OROA valve was opening or not, but this tech would have mentioned that if it was...hell, he wouldn't have even asked me any questions if it were! he is good.
has anybody seen something like this before? i have only once for sure. it was on a dx recip chiller with a water cooled condensor. total line set was maybe 5 feet.
now before anybody tells me to buy a new set of gages because they are cheap or something (who will be the first to NOT read this entire post before commenting? ) i use (and he used) the same gage for checking both. i have a small ball valve in my manifold set (kinda like the hoses with the ball valve in the end) that allows me to shut off the high side hose and open the liquid line hose and read that pressure. it is very quick and it uses the same gage.
good luck (to me this time )