I have read and lurked here for a while before posting for help. Background on the unit is 220 ton chiller system 1998 vintage with dual screws. The unit is intermittently shutting down either circuit A or B from time to time with no rhyme or reason and it never acts up while I'm onsite to catch it. Right now it's 83 degrees here and dropping to 60 or so at night. Sometimes it will go for days perfectly without a problem.

All condenser fans are running correctly operation verified
25lb of pressure drop across both circuit oil filters
UCM has updated program and OAT sensor installed
Oil level is spot on in both oil coolers
All electrical connections on oil DP switch have been verified
Compressors are starting at 40% load and then modulating up to around 70%

Condenser is visibly clean but I'm going to wash it out tomorrow to get a baseline on it.

I have not physically tested the oil pressure DP switch's yet.

But when it was 112-114 degrees this summer it ran like a top without a problem it's only once the weather cooled off in the last month these stinkin little gremlins are showing up. thanks for the help and any ideas are appreciated.