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Electrical Maintenance
127
Testing the Sensors
The controller constantly monitors the left hand
and right hand supply sensors, return sensor and
defrost (evaporator coil) sensor to determine when
to initiate a demand defrost. If a demand defrost is
requested and defrost has occurred within the last
90 minutes, the controller initiates a probe test to
check for a defective sensor.
During a Probe test, the LCD display shows
[PROBE TEST PLEASE WAIT]. The controller
operates the unit on high speed evaporator fans
only for 5 minutes. All sensor temperatures are
then compared:
•
Sensors with large temperature differences are
discarded from the control algorithm. The
controller then activates the appropriate Alarm
codes to identify the defective sensor(s).
•
If no sensors are found defective, controller
LCD display shows [RUNNING WITH HIGH
SUPPLY DIFFERENCE] message.
Sensor errors recorded during a probe test are
cleared when the next Defrost is initiated or Unit
On/Off switch is turned Off.
NOTE: A manual probe test can be performed
by a technician by selecting “SENSOR CHECK”
from the Manual Test Function menu.
A.
Coil Support Brackets
B.
Unit Front
C.
Insert Sensor at least 75 mm into coil
between Tube Rows 2 and 3.
Figure 71: MAGNUM 20 Evaporator Coil (Defrost)
Sensor Location
AXA0171
A.
Coil Support Bracket
B.
Unit Front
C.
Insert Sensor at least 75 mm into coil
between Tube Rows 2 and 3.
Figure 72: MAGNUM and MAGNUM SL Evaporator
Coil (Defrost) Sensor Location
A.
Insert Sensor into condenser coil between
Tube Rows 1 and 2
Figure 73: Condenser Coil Sensor Location
AXA0172
AXA0173
Summary of Contents for 098916
Page 5: ......
Page 11: ...Table of Contents 10...
Page 19: ...Service Guide 18...
Page 28: ...Specifications 27 Figure 2 Physical Specifications AMA313...
Page 41: ...Unit Description Features Options 40...
Page 105: ...Operating Instructions 104...
Page 155: ...Servicing The Unit 154...
Page 187: ...Index 186...
Page 189: ...Wiring and Schematic Diagrams Index 188...
Page 190: ...189 Wiring Schematic...
Page 191: ...190 Wiring Diagram Page 1 of 2...
Page 192: ...191 Wiring Diagram Page 2 of 2...