Application guidelines
21
FRCC.PC.021.A5.22
Operating conditions
Application envelope
The operating envelope for PSH scroll
compressors is given in the figure below, where
the condensing and evaporating temperatures
represent the range for steady-state operation.
The operating limits serve to define the
envelope within which reliable operations of the
compressor are guaranteed:
• Maximum discharge gas temperature: 284°F
(measured by DGT sensor),
• A suction superheat below 9°F is not allowed
due to the risk of liquid flood back,
• Maximum suction superheat of 36°F
• A subcooling above 9°F is recommended to
ensure proper liquid injection.
• Minimum and maximum evaporating and
condensing temperatures as per the opera-
ting envelopes.
Use a phase meter to establish the phase
orders and connect line phases L1, L2 and L3
to terminals T1, T2 and T3, respectively. The
compressor will only operate properly in a single
direction, and the motor is wound so that if the
connections are correct, the rotation will also be
correct.
OCS provides protection against phase reversal
and phase loss at start-up.
Apply the recommended wiring diagrams from
the section “Suggested wiring diagram logic”. The
circuit should be thoroughly checked in order to
determine the cause of the phase problem before
re-energizing the control circuit.
The phase sequencing and phase loss monitoring
functions are active during a 5 seconds window
1 second after compressor start-up (power on
L1-L2-L3)
Phase sequence and reverse
rotation protection
LED 2 Status display
Blinking sequence
Status
0.2secON/0.2secOFF
0.2secON/0.4secOFF
ALARM 25
:Phase reverse error
ACTION
: STOP COMPRESSOR
RESTART
: Come back to stable status by manual reset
0.5secON/0.5secOFF
ALARM 24
:Phase loss error
ACTION
: STOP COMPRESSOR
RESTART
: Come back to stable status by manual reset
0
20
40
60
80
100
120
140
160
180
-30
-20
-10
0
10
20
30
40
50
60
70
80
Evap. Temp. °F
Co
nd
. T
em
p.
°F
