Section 3

Description

3.1Refrigeration Unit - Front Section

The refrigeration unit is designed so that the majority of its components are accessible from the front (Figure 3.1). A manually operated venting system is located in the upper left access panel. Behind this left access panel are located the CO₂ sensor and O₂ sensor. The right access panel contains integrated components of the XtendFRESH^TM Controlled Atmosphere option. This panel may be removed to allow entry into the evaporator section where the CO₂ scrubber and other components are located.

Figure 3.1  Refrigeration Unit - Front

3.2Evaporator Section

Components of the XtendFRESH option are mounted in the evaporator section in addition to the standard refrigeration unit components. These components (Figure 3.2) include the XtendFRESH Scrubber Assembly, Motor Assembly and Sensor Package.

Air from within the container is passed to the O₂ sensor and CO₂ sensor. Data is then supplied to the controller. The controller calculates O₂ and CO₂ values in order to maintain the preset values.

Figure 3.2  Evaporator Section Components

1.Desorb Out Hose

2.   Scrubber Filter Assembly

3.   Fresh Air Solenoid

4.   Desorb In Hose

5.   CO₂ Sensor

6.O₂ Amplifier

7.O₂/CO₂ Outlet

8.O₂/CO₂ Inlet

9.Sensor Air Filter

10.O₂ Sensor   

11.CO₂ Scrubber Motor

12.            Port Cap

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3.3AutoFRESH Interface Module

The AutoFRESH Interface Module (AIM) is a device that prevents the CO₂ sensor from being calibrated when the ML3 controller is reset. The purpose of the device is to pull the CO₂ sensor zero calibration line low when the CO₂ sensor is calibrated.

3.4Ground Isolation Module

The Ground Isolation Module (GIM) is a device installed on units with a scrubber motor that has the rotational output signal. The purpose of the module is to optically isolate the scrubber motor from the ML3 controller. Troubleshooting of this device is located in AL96 Troubleshooting table.

3.5Sensor Switch Module

The Sensor Switch Module (SSM) is a device that allows for the O₂ sensor and VPS sensor to use the same ML3 controller input. Controller software manages the switching of the device and reading of the correct input. Troubleshooting of this device is located in AL09 Troubleshooting table.

3.6Safety and Protective Devices