Hi guys and gals need some advice. I have a Trane RTAA270 with the UCM system and I am having problem with two issues with this system. I work at a local university and do not have a ton of experience with the system. I am running a low suction and having a nuisance trip of low oil flow. I know for a fact that the system is charged correctly with 130 lbs of r22. I weighed it in this afternoon. Reading a manual I thought that my problem with this system was over charged. So I fell back and punted. I found a bad condenser sat temp sensor and replaced that. Now the system will run after reset. I have checked all coils for dirtiness and all fans are running correctly. I have checked oil solenoid, load and unload coils for operation. Also checked filter driers. I seen where someone on here posted about pill filters? Also on menu p2 line 27 on the amp reading. Is this reading percentage or actual amps of comp running at the time of start up. I also checked oil switch and system runs for a long while. Also checked oil pressure switch also.
I also noticed evap limiting code 77. I found a manual about within 6 degrees of set point. Does it use the sensor to determine low pressure cut out.