i was doing a pm. found walk in freezer condenser blowing cool air. long story short unit reached temp. but the low pressure control was not opening allowing the contactor to de energize. its running -20psig. so i shut down the unit. allow my solenoid valve to reopen allowing my pressure to raise. i noticed alot of oil running out at the connection. someone brazed on a gage port on the suction line about 6'' away from the comp. at about 5 o'clock spot. after leaving the job im thinking what happened was the line filled with oil so the control couldn't sense the pressure properly. i know sometimes they get stuck closed and you knock on them and it will open but i hit it pretty good but she stayed running. after installing the new one it ran for about 20 minutes before reaching temp again and it went to about -5psig then cut out when it was set for 0psig. any input