Hussmann Ingersoll Rand User Manual page 222

Johnson Controls P545NCB-25C
Supply Voltage
Power Consumption
Time Delay with Low Oil Pressure
Control Relay
Switch
Connecting Cable
Refrigerants
Anti-short Cycling Timer
Open Point (Differential Pressure)
Close Point (Differential above Close)
Allowable Operating Temp
Johnson P545NCB-25C Oil Pressure Control
When the control is energized the oil pressure monitoring is activated and the output contact is
closed, allowing the compressor contactor coil to energize and the compressor is allowed to run.
At this time the green LED is lit. If the oil differential pressure drops to the cutout set point, the
control starts timing and the yellow LED comes on along with the green LED. If the differential
pressure hasn't returned to normal within 90 seconds the control opens the output contact,
shutting the compressor off. The yellow and green LED's are shut off and the red LED is lit.
The oil pressure monitoring circuit on the P545 compares the amount of time that the oil pressure
is above the set point to the amount of time that the oil pressure is below the set point. If the oil
differential pressure is below the opening point for more than half the time, the control will time
out but the timing is extended. This will protect the compressor when there are repeated low oil
pressure signals interrupted by short periods of sufficient oil pressure.
This control has user selectable anti-short cycling delay times of 0, 35, 65, or 100 seconds. This
establishes the minimum time that the compressor will be de-energized before starting.
The control must be manually reset by pressing the reset button to be able to restart the
compressor.
Mechanical Design
Oil Pressure Control Technical Data
120 or 240 VAC + 10%, - 15%. 50/60 Hz
3 VA
90 +/- 12 seconds
Pilot duty 375 VA at 120VAC, 750 VA at
240 VAC
P400BD-1
WHA-P400-125, AWG22, 4 ft,
All typical CFC's, HCFC's and HFC's
Four selectable positions; 0,35, 65, and 100
seconds. With 100 seconds as default.
10 + 1.5 psid
Less than or equal to 3.0 psid
-40 to 131°F
Switch Shown Mounted on Compressor
8