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7–38
7.26.2
7.27 eAutoFresh Service
7.27.1
Servicing the eAutoFresh Air Filter
Removing the Air Sample Filter Element
The air sample filter element can be accessed in two ways:
1. Through the eAutoFresh side evaporator access panel (see item 11,
).
2. Through the inside of the container by lowering the upper evaporator panel.
a. By hand, unscrew and remove the filter cup from the bottom of the air sample filter assembly.
b. Remove the filter element from the filter assembly.
c. Install the new air sample filter element by reversing the above steps.
7.27.2
Checking eAutoFresh Drive System
Checking the Auto Slide:
1. To check with an ohmmeter, disconnect the four pin connector to the stepper motor. With a reliable digital
ohmmeter, check the winding resistance. In normal ambient, the motor should have 72 to 84 ohms mea
-
sured on the red/green (a-b terminals) and on the white/black (c-d terminals) leads. If an infinite or zero
reading occurs, check connections or replace the motor. If near normal or normal reading occurs, proceed
to the following sections to check out the controller.
2. To check with a SMA-12 portable stepper drive tester. The SMA-12 portable stepper drive tester (Carrier
Transicold P/N 07-00375-00) is a battery operated stepper drive which will open and close the auto slide,
which allows a more thorough check of the motor.
Checking the Slide Motor:
1. Turn unit OFF.
2. Disconnect the four pin connector from the Stepper Drive to the Stepper Motor (see
).
3. Attach the SMA-12 portable stepper drive tester to the Stepper Motor.
4. Set the SMA-12 pulse per second (PPS) to one PPS and press button to open or close the valve. Each LED
should light sequentially until all four are lit. If an LED fails to light, it indicates an open on that leg caused by
a poor connection or an open coil. Repair or replace as required to achieve proper operation.
Figure 7.23 Stepper Components
5. Set the SMA-12 step rate to 200 PPS. Press open or close while watching the slide mechanism for move
-
ment, this is an indication that the motor is working.
6. If the slide moves using the SMA-12, but fails to move when connected in the unit (refer to “Checking the
Drive Module” in the section that follows.)
Checking the Drive Module:
1. Turn unit OFF.
2. Disconnect the four pin connector to the Stepper Motor.
Stepper Drive (SD)
Stepper Motor (AF)
