YORK YK — Oil - Variable speed pump - Setpoint not achieved

The panel shows Oil - Variable speed pump - Setpoint not achieved. The manuals also print it as Oil - Variable Speed Pump - Setpoint Not Achieved; both spellings name the same event, which belongs to the chiller's safety shutdowns.

A safety shutdown of "P" compressors, raised when the minimum allowed oil pressure is not achieved. The condition is evaluated while the system is in prelube, in run, or in coastdown; the pressure levels and the time windows are set out under causes and settings.

• The differential oil pressure stays below 35.0 PSID for 5 continuous seconds — either in the final 10 seconds of the prelube period or in the first 15 seconds of run.
• Once the first 30 seconds of run have elapsed, the differential oil pressure runs more than 5.0 PSID below the active oil pressure setpoint while the speed command from the microboard is held at 60 Hz, again for 5 continuous seconds.

• Prelube and run-start trip point: differential oil pressure below 35.0 PSID, watched through the last 10 seconds of prelube and the first 15 seconds of run.
• Run trip point: the active oil pressure setpoint minus 5.0 PSID, applying at any moment after the first 30 seconds of run while the microboard speed command sits at 60 Hz.
• Trip delay: the low-pressure condition must persist for 5 seconds continuously.
• History on "P" compressors: the trip level was 25.0 PSID before October 2004 and 35.0 PSID from then on, the value used for all other compressors.

Reset, in the manual's own words: The chiller can be started after the Clear button is pressed next to the listed event on the Systems Details Screen.