Chiller tripping on low oil net pressure

[Grevinm]

Hi,
I am having daikin MacQuay WSC 087 model no 500TR centrifugal chiller,serval times when i m starting the chiller it is tripping on low oil delta pressure, low net oil pressure set point is 60psi, but when chiller is getting tripped net oil presuure is always around 64 to 68 psi then y my chiller is continously tripping on low oil delta pressure after restarting it to 2 toi 3 times it is running, but after shut off when again i m starting it the same problem occurs, so pls help me out to solve this problem

[goshen]

Hi
check your oil filter !
calibrate sensores.
and make sure your condensing water isnt too cold when starting the unit .
how old is the unit ?
when was the last time you sent the oil for analasys?
good luck

[Grevinm]

thnx for reply.
oil filter is ok...sensors are aslo ok...when i am starting condenser temperatue is near about 30 deg... orignal oil viscocity is 32.8 at 40 deg now its deviated -19.8.
as of now i have incrased oil temperature for maintaning its pressure. but from viscocity what u think should i changed oil???
chiller is 5 years old.