Thermo King SLXi Spectrum, Maintenance Manual

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Unit Description 5-15
Electric Operation
Continuous Mode (includes Modulation)
• Cool
• Modulated Cool
1
• Null 2
• Modulated Heat
1, 3
• Hot Gas Heat 3
• Full Heat
3
(hot gas and electric heaters)
• Defrost (hot gas and electric heaters)
1 ETV operation is locked out if controller setpoint is below Fresh/Frozen temperature setting.
2
Null mode ONLY when the setpoint is BELOW the Fresh/Frozen temperature setting.
3
Null mode if controller setpoint is below the Fresh/Frozen temperature setting.
CYCLE-SENTRY Mode
1, 2
• Cool
• Null
3
• Hot Gas Heat 4
• Full Heat
4
(hot gas and optional electric heaters)
• Defrost (hot gas and optional electric heaters)
1
ETV operation is locked out during Cycle-Sentry operation.
2
If battery condition requires unit start-up during Null mode, unit starts and operates in Hot Gas Heat or Cool.
3 Unit mode is Null when battery charge level is satisfied.
4 Null mode if setpoint is below Fresh/Frozen temperature setting.
Modulation
The modulation temperature range is factory set at -9 C to 27 C. The lower limit (-9 C) is adjustable through the keypad to -4C.
The upper limit (27 C) can be field adjusted from 27 C down to -9 C. Ito -4 C or -9 C depending on setting. If the upper limit is
set to -4 C or -9 C, the modulation mode is completely disabled.
The Modulation mode is disabled when the controller setpoint is above or below the modulation temperature range, when the
unit is in Defrost, and when the CYCLE-SENTRY switch is in the CYCLE-SENTRY position (except in Cycle-Sentry Fresh
range).
Defrost
Defrost can be manually initiated through the controller keypad, or automatically initiated controller defrost timer or
controller Demand Defrost algorithm. A demand defrost occurs when the difference between the return air temperature,
discharge air temperature and evaporator coil temperature becomes excessive.
Defrost can be initiated any time the evaporator coil temperature is below 7 C. If the unit is in Null (on Engine or Electric
Standby Operation), initiating defrost will cause the unit to start and operate. When a defrost cycle is initiated, the controller
energises the damper motor or solenoid, pilot solenoid, heater contactor and Defrost icon. The controller maintains the
In-range signal during defrost.
The unit remains in defrost until the evaporator coil temperature increases to 14 C. If the evaporator coil temperature does not
rise to 14 C within the defrost duration time limit (30 or 45 minutes), the controller terminates defrost. The evaporator then
returns to operation based on controller demand. In this case the unit will generate an alarm.