Thermo King 098916, Руководство по обслуживанию

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Operating Theory
109
1
Setpoint temperature and Economy mode setting
determine the evaporator fan speed:
Normal Operation (Economy mode off):
Chill
Loads — High speed fans; Frozen Loads — Low
speed fans.
Economy mode set to On:
Chill Loads — Fans
switch from high speed to low speed when
temperature is in-range. Frozen Loads — Low
speed fans during cooling; fans are off during Null
mode but operate on low speed for 5 minutes
every 45 minutes.
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.
NOTE: Condenser fan does not operate when
the water pressure switch (option) is open.
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.
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