Flooded type water cooled screw chiller (PCB Control)
38
a. When compressor start, the return oil solenoid valve is opened ,closed after 10 minutes.
b. When compressor is running ,from compressor start to 50%,every 30 minutes to open return oil
solenoid valve 2 minutes.
c.
When compressor shut down, with the compressor unloaded into 50% return oil solenoid valve open
3 minutes.
d. When oil level protection occurs, the return oil solenoid valve is opened, closed after recovery.
5). EXV controller Control
a. EXV controller wiring principle
EXV controller is started by main base controller. It detects discharge pressure, temperature and
calculate discharge superheat. Then it control EXV opening depending on superheat. If it is wrong .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, only display running status.
LED
Light
Extinguish
Flicker
NET
Can
be
connected
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
-
off
12Bar
32min
12Bar
32min
12Bar
24V DC
Discharge pressure
transmitter
Discharge temp.
thermistor
Start/stop relay
From controller
EXV
CAREL EXV controller EVD
Alarm output
to controller