Carrier 69NT40-561-300, Operation And Service Manual

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T-365 5–2
1. Make sure that the start − stop switch (ST, on control panel) and circuit breakers CB − 1 (in the control box and
CB − 2 (on the transformer) are in position “0” (OFF). Plug in and lock the 460 VAC power plug at the recep-
tacle on the transformer.
2. Plug the 230 VAC (black) cable into a de − energized 190/230 VAC, 3 − phase power source. Energize the
power source. Set circuit breakers CB − 1 and CB − 2 to position “I” (ON). Close and secure control box door.
Figure 5.1 Autotransformer
5.3 ADJUST FRESH AIR MAKEUP VENT
The purpose of the fresh air makeup vent is to provide ventilation for commodities that require fresh air circulation.
The vent must be closed when transporting frozen foods.
Air exchange depends on static pressure differential, which will vary depending on the container and how the con-
tainer is loaded.
Units may be equipped with a vent position sensor (VPS). The VPS determines the position of the fresh air vent
(upper or lower, as equipped) and sends data to the controller display.
5.3.1 Upper Fresh Air Makeup Vent
Two slots and a stop are designed into the Upper Fresh Air disc for air flow adjustments. The first slot allows for a
0 to 30% air flow; the second slot allows for a 30 to 100% air flow.
To adjust the percentage of air flow, loosen the wing nut and rotate the disc until the desired percentage of air flow
matches with the arrow. Tighten the wing nut.
To clear the gap between the slots, loosen the wing nut until the disc clears the stop.
Figure 5.2 gives air exchange values for an empty container.
Higher values can be expected for a fully loaded container.
Dual Voltage
Modular
Autotransformer
Circuit Breaker (CB-2)
230-Volt
460 VAC Power
Receptacle