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ESI Outdoor Unit Installation Instruction
05.2018
Manufacturer reserves the right to change at any time for specifications or designs without notice and incurring obligations.
Display
Low pressure sensor fault (LP)
1.Error definition and method to check:
The low pressure sensor is open or shorted.
The voltage between CN9 pin(1) and (2) is not in the range 0.70~4.50VDC.
2.Possible causes:
Damaged main control board
Loose connection at port on main control board.
Damaged low pressure sensor
Too little refrigerant remains in the system.
3
2
1
L
ow
pr
essure
se
nsor
red
White
black
CN9
5V
Measure voltage within this space (
Low Pressure Sensor Voltage Characteristics C*
)
IC A/D
input
GND
YES
NO
Is the low pressure sensor connected to CN9?
Reconnect the sensor
Are the service valves opened?
YES
NO
Open stop valves
Low pressure at gas stop valve to malfunction is 24.5 psig.
NO
YES
Check any refrigerant clogging
and shortage.
Connect a gauge on service valve to test low pressure, check
whether the pressure transduction is measuring properly?
NO
Replace the pressure sensor
Replace the main control board
YES
Cycle power the unit, can it operate under backup running?
NO
Check the cable connector
YES