16
17
Crankcase Heaters
Crankcase heaters are very effective in keeping liquid
out of the compressor and are recommended for
all installations. The heater should be on when the
compressor is stopped.
At the time of initial startup, or after any extended pe-
riod without power, the heater should be energized 12
hours before starting the compressor. Long off periods
are common in cold stores holding seasonal products, so
it is particularly important to turn on power to the unit
12 hours before restarting after a long idle period. A 220
V 60 W heater is supplied as standard equipment.
Startup and Operation
Leak / Pressure Testing
The compressor has been pressure tested in the factory.
It is not necessary for the system manufacturer or
installer to pressure test or leak-test the compressor
again although the compressor will normally be exposed
to the pressure used as part of system testing. Consider
personal safety requirements and refer to nameplate test
pressures prior to testing.
Figure 14.
Sensor Location
Differential Oil
Pressure Sensor
Optical Oil Level Sensor
Discharge Port
Temp. Sensor
Vapor In Temp.
Sensor
Vapor Out
Temp. Sensor
Gland
(Waterproof)
Number
Gland 1
Gland 2
Gland 3
Gland 4
Gland Description
For “PWR” and
“Demand” Connector’s
Wires
For “CCC” Connector’s
Wires
For “Alarm” Connector’s
Wires
For Compressor Motor
Power Supply Wires
One jacket line with two
wires goes through the
joint
One jacket line with two
wires goes through the
joint
One jacket line with two
wires goes through the
joint
One jacket (PVC) line
with four wires goes
through the joint
Wire Function
A(Red) and B(Black):
Controller Power Supply
Input(220-240VAC
50/60Hz)
E(Brown) and F(Blue):
Compressor Diagnostic/
Protection Contact
Output
H(Brown): Output For
Alarm Devices
I, J, K: Compressor
Motor Power Supply
L: Earth Wire
Wire Connection
Wires A and B: “PWR”
(Green) connectors
Wires E and F: “CCC”
(Green) connectors
Wire H: “Alarm”
(Orange) connectors
N/A
Gland Internal
Diameter Range
5-10 mm
5-10 mm
5-10 mm
18-25mm
Jacket Line
Requirement
Internal wire size: 18-20 AWG
Internal wire seize: 8
AWG or above (4 wires
in total)
Recommended wire size: 18 AWG
Rated voltage: 300V/500V
Rated voltage:
600V/1000V
Reverse rotation and lack of pumping have the same
symptoms: the discharge pressure does not rise and
the suction pressure does not fall. If the control module
senses that the differential pressure switch has not closed
after a short time delay, the compressor will stop, an error
message will be displayed on the control board, and a
timer will be started. Three more attempts will be made
to start and if differential pressure is not established, the
compressor will be locked out. The alarm contact will close
and can be used by the installer to turn on a light, sound
a bell, etc. The alarm contact is voltage-free allowing
maximum fl exibility with regard to the type of alarm
device that can be connected. The alarm relay contact is
rated at 250 VAC 1A and 30 VDC 1A.
High discharge temperatures often occur when the
system is short of refrigerant: suction temperature rises,
bubbles form in the liquid line and there is insuffi cient
liquid to feed the injection EXV properly. The control
module will stop the compressor, display a fault code and
close the alarm relay. After a time delay, the compressor
will restart. High discharge temperature alarms indicate
a serious system problem, and corrective action must
be taken to avoid long term compressor damage and
possible product loss.
Oil stored in compressor high side oil tank keeps same
pressure and temperature as discharge gas. When oil
flows from oil tank to bearing, it goes through the heat
exchanger in a separate passage for cooling. High oil
temperature could cause to lubricating deterioration
as well as bearing failure. If the oil temperature goes to
its upper limitation, the control module will display an
alarm code. If oil temperature continues to increase up
to a setting point, compressor will be tripped, and could
restart after time delay.
Warning
Oil level is monitored by an optical sensor in the high
side oil sump. If the level falls to the minimum allowable,
a timer will start and the compressor will be stopped if
suffi cient oil has not returned to the sump in one minute.
Figure 13.
Terminal Box Location For Wiring
Remove Terminal Box Cover
for Customer Wiring
M25, 6 Sensors
M20, EXV Wires
M20, Motor Power
3xM16, Other Wires
Table 1: Glands and Wires
Warning
Warning
Warning
Oil Temperature Sensor
Two restarts will be attempted after short delays, and
if the oil level does not recover, the compressor will
be stopped and locked out. An alarm message will be
displayed and the alarm relay will close.
Motor overheat may occur when the suction gas
temperature is abnormally high, mass flow is low and
discharge pressure is also high. Four thermistors are
embedded in the windings and monitored by the control
module. If the module senses that the winding temperature
is high, it will stop the compressor and start a timer. A
restart will be attempted when the windings have cooled
and the timer has timed out. The compressor will not be
locked out, but the cause of overheat must be investigated
to prevent long term compressor damage. Motor overheat
can be caused by a mechanical problem, which, if not
rectifi ed quickly, could cause complete compressor failure
and system contamination. Common mechanical problems
that lead to motor trips include worn bearings or worn scroll
sets as a result of overheating.
Oil may not be visible when compressor is stopped. Run
compressor until conditions are stable. Oil level should be
between 1/4 and 3/4 sight glass.
Checking Thermistors and Sensors
Table 2 provides resistance values of the thermistors at
several useful temperatures.
Use a voltage no higher than 3 VDC when testing.
An ice bath can be used at 0
o
C and boiling water can be
used at 100
o
C.
Table 2. Thermistors
Location
Temperature
0
o
C
25
o
C
100
o
C
Discharge
326 K Ohm
100 K Ohm
7 K Ohm
Oil
326 K Ohm
100 K Ohm
7 K Ohm
Vapor In
28 K Ohm
10 K Ohm
950 Ohm
Vapor Out
28 K Ohm
10 K Ohm
950 Ohm
For the motor thermistor chain, the trip resistance is >
4.5 K Ohms and the reset resistance is < 2.75 K Ohms.
Resistance at room temperature should be < 500 Ohms.
If the oil level switch is not functioning correctly, the
optical part can be easily changed without breaking
into the system. Malfunction is also possible if the lens
is coated by system contaminants. The lens will need to
be removed and cleaned to restore correct operation.
Warning
Caution
Caution
Caution
