Pre-lube Oil Pressure = This is the pre-lube oil pump failure safety. If the pre-lube oil pressure does not rise above the alarm setting for a time exceeding the Minimum Pre-lube Time and the pump run runs longer than the Pre-lube Pump Time Limit, an alarm or trip will occur. These time limits are set on the Timer menu screen. Pre- lube oil pressure is defined as manifold pressure minus discharge pressure. The purpose of this safety is to insure that we have oil being injected into the compressor during the starting of the compressor - to insure adequate lubrication.
•Low (Run) Oil Pressure = This is the running oil pressure safety. The normal alarm and trip set-points of this safety are “massaged” as soon as the compressor starts. The “Pre lube Oil Pressure” Alarm and Trip set-points are jammed into this safety set-points for a time of the “Oil Pressure Bypass” timer (typically 60 seconds). After this timer expires, then the set-points return back to the normal settings. The action of massaging the set-points for about a minute allows the (Run) Oil Pressure to build up to normal running pressures after the compressor starts. After the Oil Pressure Bypass Timer has expired, the Oil Pressure must be above the normal set-points, or else an Alarm or Trip will occur. An alarm or trip will be active if the oil pressure should drop below the normal set-point values after the Oil Pressure Bypass timer has expired. This time limit is set on the Timer menu screen. Run oil pressure is defined as manifold pressure minus suction pressure.
•High Filter Differential Pressure Start = This safety allows a higher than normal filter differential pressure to exist during the first minute after a compressor starts. This allows time for cold oil that is present in the oil pip- ing and filters to be passed and replaced with warmer oil. After a time delay (setting of the Filter Diff Pressure Safety Changeover timer), then this safety is deactivated and the High Filter Differential Pressure-Run alarm and safety set-points become active. An alarm or trip will be active if the filter differential (= Filter Inlet Pressure minus Filter Outlet Pressure) exceeds by the set-point value.
•High Filter Differential Pressure Run = This safety set-point is active when the compressor has started and the Filter Diff Pressure Safety Changeover timer has timed out. An alarm or trip will be active if the filter differential (= Filter Inlet Pressure minus Filter Outlet Pressure) exceeds by the set-point value.
•High Motor Amps : This safety set-point is active after the Volume Decrease At Start Timer expires (this timer is not settable by the operator). A trip will occur if the motor amperage exceeds the safety set-point value. For a motor with a 1.15 Service Factor, the trip set-point should be set at 125% of the motor full load amperage value. The alarm set-point should be set at 120% of the motor full load amperage value.
