MCAC-CTSM-2018-1
Flooded type water cooled screw chiller (MIC)
33
a. When compressor starts, the return oil solenoid valve is open, and it will close after 10 minutes.
b. When compressor is running, from compressor starting at 50%, every 30 minutes open for return oil
solenoid valve for 2 minutes.
c. When compressor shuts down, with the compressor unloaded to 50% return oil solenoid valve open
3 minutes.
d. When oil level protection starts, the return oil solenoid valve will open and then closed after recovery.
5). EXV controller Control
a. EXV controller wiring principle
EXV controller is started by the main base controller. It detects discharge pressure, and temperature and
calculates discharge superheat. Then it controls EXV opening depending on the superheat. If it is
incorrect, EXV will output alarm signal to main base controller.
b. Controller display
The interface of EXV controller cannot display and set the parameter on unit, It can only display running
status.
If the parameters need to be displayed and set, change the interface..
LED
Light
Extinguish
Flicker
NET
Can connect to
the network
Not
connected
Communication
failure
OPEN
Open the valve -
Disable the drive
CLOSE
Close the valve -
Disable the drive
Activate the
alarm
-
-
Drive power
The drive is
not connected
to power
supply
-
24V DC
Discharge pressure
transmitter
Discharge temp.
thermistor
Start/stop relay
From controller
EXV
CAREL EXV controller EVD
Alarm output
to controller