Operating Theory
130
1
Setpoint temperature and controlling mode setting determine the evaporator fan speed:
Normal Operation:
Chill Loads — High or low speed fans; Frozen Loads — Low speed fans or no fans.
2
Vapor injection valve:
Chill, Frozen or Power Limit Mode:
When the cool capacity is 100 percent.
Compressor High Temperature Protection:
When the compressor discharge temperature exceeds 138 C
(280 F).
3
Condenser fan pulses on and off on a 30 second duty cycle to maintain a minimum condenser
temperature:
Chill Loads:
Controller maintains a minimum 30 C (86 F) condenser temperature.
Frozen Loads:
Controller maintains a minimum 20 C (68 F) condenser temperature.
4
Digital Control valve modulates: Chill Loads — whenever the unit is in a Cooling mode; Power Limit —
whenever the unit is in Power Limit mode.
Dehumidification:
When the Dehumidify mode is set to On, the supply air temperature must be In-range
to energize the electric heaters.
•
When the humidity is 2 percent or more above humidity setpoint, the controller (energizes) the
heaters.
5
Controller energizes electric heaters for heat, defrost and dehumidification:
Heat mode (compressor off):
If supply air temperature is too low, heaters pulse on and off on a 60 second
duty cycle.
Defrost mode:
Heaters are on until evaporator coil temperature increases to terminate defrost.
Operating Mode Function Chart
Chill Loads
Setpoints at -9.9 C
(14.4 F) and Above
Frozen Loads
Setpoints at -10 C
(14 F) and Below
Cool w/Mod
Heat
Defrost
Cool
Null
Defrost
Unit Function
•
1
•
Evaporator Fans High Speed
1
•
1
•
•
1
Evaporator Fans Low Speed
1
•
•
1
•
Evaporator Fans Off
1
•
•
Proportional-integral Derivative (Supply Air) Control
•
•
Return Air Sensor Control
•
•
Evaporator Coil Sensor Control
•
•
Compressor On
•
•
Compressor Vapor Injection On (valve energized)
2
•
•
Condenser Fan On
3
•
•
4
Digital Control Valve Modulating (energized)
4
•
5
•
•
•
Electric Heaters Pulsing or On (energized)
5
Summary of Contents for 098203
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Page 3: ...MAGNUM TK 60275 4 MM Rev 3 08 15 Copyright 2012 Ingersoll Rand EMEIA Printed in Ireland...
Page 193: ...Refrigeration Maintenance 191 Figure 163 Filter Drier...
Page 200: ...Refrigeration Maintenance 198 Figure 169 Receiver Tank Figure 170 Water Cooled Condenser Tank...
Page 257: ...255 Schematic Diagram RELEASED 19 Sep 2013...
Page 258: ...256 Wiring Diagram Page 1 of 2 RELEASED 19 Sep 2013...
Page 259: ...257 Wiring Diagram Page 2 of 2 RELEASED 19 Sep 2013...
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