Dehumidification; Condenser Fan - Maersk Container Industry Star Cool SCI-20 Operating And Service Manual

6.7 Dehumidification

The dehumidification function dehumidifies air in the container by means of a heater. This function
can only be activated if the temperature control function is active. Dehumidification is achieved by
decreasing evaporator surface temperature. This is done through activation of the heater and letting
the temperature control increase cooling capacity resulting in an evaporator temperature descending.
This function has 3 modes:
1. Off
The dehumidification function is in the OFF position.
2. Active
The heater (Hevap) is activated when RH is more than RHSet and deactivated when RH is less
than RHSet – 3 [%]. The humidity setpoint can be set in the range 50% to 95% relative humid-
ity. The range 50% to 64% is only possible with no fresh air/evaporator ventilation in low speed.
The range 65% - 95% is possible to run with fresh air/evaporator ventilation in high speed.
3. Override
Accessing override mode if:
- Cooling demand exceeds 80% capacity
- Large demand for heating
- PTI
- A fatal alarm is active
- When operating without FC
- Manual operation is active
- Defrosting
Other comments
The dehumidification icon
The heat icon follows the current state of the heater.
If dehumidification is active:
Defective sensor(s)
RH

6.8 Condenser fan

Condenser fan control will reduce condenser pressure through condenser ventilation. The condenser
pressure control also monitors the compressor outlet pressure in case of water-cooling. This function
is activated when control is being in the automatic mode.
Condenser pressure control has two primary modes:
1. Air-cooled
In Air-cooled mode ventilation takes place in the following way:
Depending on the compressor outlet pressure, the fan is Off or runs in 2 different speeds: High and Low.
The fan runs in 4 modes: Off, Low-speed, High-speed and a cycle shifting between high and
low-speed in two minutes intervals.
If Tamb is more than 48°C (118°F) or the compressor outlet pressure remains constantly high,
the condenser fan constantly runs at high speed.
2. Water-cooled
If the condenser fan is constantly on for more than 1 hour, an alarm will be given.
The fan runs in 4 modes: Off, Low-speed, High-speed and a cycles shifting between high and
low-speed in two minutes intervals.
Defective sensor(s)
Pdis
Tamb
Tret, Tevap and Tsup1
Tamb and Tinternal
is shown in the display even if override is active.
Substitution sensor/Action
Stop dehumidification
Substitution sensor/Action
Start up:
Condenser fan speed = slow
Chill/Frozen mode:
Condenser fan speed depends on
ambient temperature.
Tamb = Tinternal
Tact = Tsup2 + constant
Tc min
Dehumidification
function
Off
Enabled
Active
Alarm
614, Humidity deactivated
Alarm
203, Pdis invalid
129, Tamb invalid
102/123/105, Tret/Tevap/Tsup 1 invalid
129, Tamb invalid
Operating and service manual
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