Have a 1500 gallon sump of Royal Purple Synergy 320 oil to lubricate a large mill drive gearbox. Routine oil analysis has indicated normal conditions in all areas except for the TAN. Reference reading for TAN was 4.190. The last five tri-annual readings have been showing a decrease - 3.139 - 2.686 - 2.458 - 1.825 - 0.722.
This is the first time I've seen a decreasing TAN rather than an increasing number. Can anyone explain this one to me?
Visc. 321cSt @ 40C is steady
KF 57 ppm
Water FTIR 12.0
The only additive in reference is phosphorus at 364 ppm, with only slight variations.
Thanks for any help, Hal