Air Cooled Oil Cooler Fan; External Electric Oil Pump; Oil Pressure Safety Switch; Air Cooled Aftercooler - Step Type - Emerson Vilter PLC Operation Manual

Section 2 • Operational Descriptions

AIR COOLED OIL COOLER FAN

If installed, the air-cooled oil cooler fan starts with the
blower motor and runs as long as the blower motor is
running.

EXTERNAL ELECTRIC OIL PUMP

If installed, the external electric oil pump starts with the
blower motor and runs as long as the blower motor is
running.

OIL PRESSURE SAFETY SWITCH

If installed, the oil pressure safety switch will shut down
the blower if oil pressure is lost.
AIR COOLED AFTERCOOLER – STEP TYPE
If installed, the step type air-cooled aftercooler is a heat
exchanger that uses multiple fans to remove heat from
the gas discharged from the blowers. The number of
fans that run is determined by the gas temperature at
the outlet of the aftercooler.
The controller starts and stops fans in a sequence to con-
trol the gas temperature at the outlet of the aftercool-
er. When the aftercooler outlet temperature exceeds
TARGET
START
TEMPERATURE OR
PRESSURE
STEP #

Figure 2-3. Operational Diagram - Air Cooled Aftercooler (Step Type)

2 – 6
the desired temperature plus a deadband, fans will be
turned on after a time delay to add more cooling. When
aftercooler outlet temperature drops below the desired
temperature minus a deadband, fans will be turned off
after a time delay.
• When the blower package is stopped, all aftercooler
fans are turned off.
• When the blower package is running and the after-
cooler outlet temperature rises above the "Start
Aftercooler At" temperature set in the "Step Type
Aftercooler Setpoints" screen, the fi rst fan (or group
of fans) will start.
• When the blower package is running and the after-
cooler outlet temperature is above the deadband, a
fan (or group of fans) will start each time through the
"Step Dwell Time."
• When the blower package is running and the after-
cooler outlet temperature is below the deadband, a
fan (or group of fans) will stop each time through the
"Step Dwell Time."
• Once started, the fi rst fan or group of fans will remain
running until the blower stops.
FANS TURNING ON
Blower Package PLC Operation Manual •Vilter/Emerson • 35391BLP
FANS TURNING OFF