Recently I changed oil pumps on two 30GTR Carrier Chillers. One chiller was 2 years old and the other about 4 years old. The oil pressure (differential) would erratically drop to 5 psi. I did not visibly see any defect or worn areas on the removed pump assembly. These replacements apparently resolved the problems (note: I later also change out a bad oil pressure switch). Now I have a third 30GTR unit about 4 years old that's also faulting on the oil pressure alarm. These units are too new to be having this type of problem. I haven't spoke to Carrier yet, but I was wonder if anyone has been having similar problems or know of a possible factory problem?
p.s. All out of warranty work.