Carrier 69NT20-531-300 manual Operation, 69NT Fresh AIR Makeup

SECTION 4 OPERATION

4.1 INSPECTION (Before Starting)

WARNING

Beware of unannounced starting of the evaporator and condenser fans. The unit may cycle the fans and compressor unex- pectedly as control requirements dictate.

a. If container is empty, check inside for the following:

1.Check channels or “T” bar floor for cleanliness. Channels must be free of debris for proper air cir- culation.

2.Check container panels, insulation and door seals for damage. Effect permanent or temporary repairs.

3.Visually check evaporator fan motor mounting bolts for proper securement (refer to paragraph 6.17).

4.Check for dirt or grease on evaporator fan or fan deck and clean if necessary.

5.Check evaporator coil for cleanliness or obstruc- tions. Wash with fresh water.

6.Check defrost drain pans and drain lines for obstruc- tions and clear if necessary. Wash with fresh water.

7.Check panels on refrigeration unit for loose bolts and condition of panels. Make sure T.I.R. devices are in place on access panels.

b. Check condenser coil for cleanliness. Wash with fresh water.

c. Open control box door. Check for loose electrical connections or hardware.

d. Check color of moisture-liquid indicator. e. Check oil level in compressor sight glass.

4.2 CONNECT POWER

WARNING

Do not attempt to remove power plug(s) be- fore turning OFF start-stop switch (ST), unit circuit breaker(s) and external power source.

WARNING

Make sure the power plugs are clean and dry before connecting to any power receptacle.

4.2.1 Connection To 380/460 vac Power

1.Make sure start-stop switch (ST, on control panel) and circuit breaker (CB-1, in the control box) are in position “0” (OFF).

2.Plug the 460 vac (yellow) cable into a de-energized 380/460 vac, 3-phase power source. Energize the power source. Place circuit breaker (CB-1) in posi- tion “I” (ON). Close and secure control box door.

4.3 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 container is loaded.

4.3.1 Upper Fresh Air Makeup Vent

Two slots and a stop are designed into the disc for air flow adjustments. The first slot allows for a 0 to 30% air flow, and 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 4-1 gives air exchange values for an empty container. Higher values can be expected for a fully loaded container.

AIR	69NT FRESH AIR MAKEUP
	ZERO EXTERNAL STATIC 50HZ
FLOW
(CMH)	For 60HZ operation multiply curves by 1.2

											T-BAR
240											1-!/2”
210											T-BAR
											2-%/8”
180											T-BAR
											3”
150
120
90
60
30
0	0	10	20	30	40	50	60	70	80	90	100

PERCENT OPEN

Figure 4-1 Make Up Air Flow Chart

4-1 T-309