T-CU19-JAN24-1
Page 20
Mechanical Safety Pressure
Switch
Mechanical high-pressure switch will cut out the STO
connection on the drive to stop the compressor when
discharge pressure is higher than the cut-out pressure of the
manual reset cartridge type pressure switch: cut out 28barg/
cut in 22barg.
•
Once tripped by high pressure switch, it will create
Alarm: ALW25: A1. Power+ and ALC01: Compressor1
alarm1. High pressure switch needs to be manual reset
by access to the part from hinged right door (for JEHSI-
033-B3-M and JEHSI-066-B3-M) and hinged front top
door (for JEHSI-087-B4-M).
•
Alarm ALB04 High cond. Press. is only triggered by high
pressure transducer through setting in Mask De02
Condenser high pressure
–
threshold: 28barg;
Condenser high pressure - alarm diff: 7barg; Condenser
low pressure - alarm delay: 5s. To reset ALB04 alarm,
remove the fault and hold down button ALARM until no
active alarm appears.
Low pressure alarm could be either triggered by pressure
switch or low-pressure transducer.
•
When compressor turns off by activation of force off,
“Forced Off” only
shows in moment on info screen and
no logging on alarms history.
•
When setting of Mask Cae26 Suction low pressure
alarm
–
threshold:
1.2bar
, Cae27 turn off compressor:
NO
. Alarm history will record
ALB16
low pressure alarm
if system suction pressure falls below 1.2bar for
delayed time set, without turning off compressor.
•
If alarms triggered by low pressure switch. Alarm
ALB01
Com. Dig. Low press. will be logged in history. Default
setting: semiautomatic reset 5/60min. Manual reset by
holding
down on the button “ALARM” until active alarm
is clear, is required on the 5
th
times of this alarm occur in
an hour. Low pressure setting had been configured in
such a way that it is the first device to cut in and last
device to cut out the system.
For standalone application, compressor is
force off at threshold value set in Mask Caf95
(2.5barg) to avoid recycling pump down.
When the setpoint in Mask Cab03 is set lower
than 2.7barg, threshold value in Mask Caf95 needs to be
adjusted to avoid unnecessary unit trigger off.
Do not adjust the suction low pressure alarm
–
threshold
in Mask Cae26.
High Discharge Temperature
Management
•
The envelope of a BLDC compressor is also limited by
high discharge temperature. If the discharge
temperature continues to rise, a safety algorithm will
be activated to gradually reduce it. The corresponding
parameters are under submenu: Compressors -
>Advanced -> mask Hb02, Hb03, Fdb04.
•
Near the limit value, compressor speed will start
slowing, until stopping on reaching the alarm with the
high temperature alarm is activated. The alarm is reset
manually.
Figure 17: Discharge Temperature Management
110
0
C
ALW28: Compressor Stops
Alarm
105
0
C
Speed Deduction
Limit
100
0
C
Vapor Injection
Action Distance
90
0
C
Acceleration rate reduction
Normal Operation
Speed reduction limits - alarm limit
Speed reduction - 3% of max. speed
E.g. if max 100rps,
3rps every 90s; 3rps every 1
0
C
Vapor injection - EEV control based on (Fdb04):
SH if T_disch.< min temp.
T_disch if T_disch>min temp limit, opening to
max % at max temp. limit (Fdb04)
Note: EEV Vapor Injection not applicable to *-M-3*
models
Speed control based on discharge temperature (Hb03):
•
Speed reduction: 3% of max. speed, e.g., if max.
speed is 100rps. 3rps every 90s; 3rps every 1
0
C
•
Compressor stopping at high temperature alarm.
EEV vapor injection control based on (Fdb04):
•
SH if T_disch. < min. temp
•
T_disch if T_disch.> min. temp limit, opening to
maximum % at max. temperature limit.
