Trane Thermo King Magnum Plus - Operating Theory and Mode Chart; MAGNUM+ Operating Mode Function Chart

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OPERATING THEORY
OPERATING THEORY
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.
MAGNUM+ 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