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clear the gap between the slots, loosen the wing nut until
the disc clears the stop. Figure 4-2 gives air exchange
values for an empty container. Higher values can be
expected for a fully loaded container.
69NT40 FRESH AIR MAKEUP
AIR
ZERO EXTERNAL STATIC 50HZ
FLOW
(CMH)
240
210
180
150
120
90
60
30
0
0 10 20 30 40 50 60 70 80 90 100
PERCENT OPEN
For 60HZ operation multiply curves by 1.2
Figure 4-2 Make Up Air Flow Chart
4.3.1 Fresh Air Vent Position Sensor (VPS)
The VPS allows the user to determine position of the
fresh air vent via function code 45. This function code is
accessible via the code select key.
The vent position will display for 30 seconds whenever
motion corresponding to 5 CMH (3 CFM) or greater is
detected. It will scroll in intervals of 5 CMH (3 CFM).
Scrolling to Function Code 45 will display the Fresh Air
Vent Position.
Data Recording of the Sensor Position -- The position of
the vent will be recorded in the DataCorder whenever
the unit is running under AC power and any of the
following occur:
Trip start
On every power cycle
Midnight
Manual change greater than 5 CMH (3 CFM) and
remains in that position for 5 minutes.
NOTE
The user has 5 minutes to make necessary ad-
justments to the vent setting. This time begins
on the initial movement of the sensor. The vent
can be moved to any position within the 4 min-
utes. On completion of the first 4 minutes, the
vent is required to remain stable for the next 4
minutes. If vent position changes are detected
during the 5 minutes stability period, an alarm
will be generated. This provides the user with
the ability to change the vent setting without
generating multiple events in the DataCorder.
4.3.2 Lower Fresh Air Makeup Vent
a. Full Open or Closed Positions
Maximum air flow is achieved by loosening the wing
nuts and moving the cover to the maximum open
T-285
position (100% position). The closed position is 0% air
flow position.The operator may also adjust the opening
to increase or decrease the air flow volume to meet the
required air flow.
b. Reduced Flow for Fresh Air Makeup
On some models the air slide is supplied with two
T-BAR
adjustable air control disks. The fresh air makeup can be
1-!/2"
adjusted for (15, 35, 50 or 75) cubic meters per hour
(CMH). The air flow has been established at 60HZ
T-BAR
power and 2 1/2 inch T bar and with 15mm (.6 inch) H2O
2-%/8"
external static above free blow.
Loosen the hex nut and adjust each disk to the required
T-BAR
3"
air flow and tighten hex nut.
The main air slide is in the fully closed position
during reduced air flow operation.
c. Adjustment
The air slide is supplied with two adjustable air control
discs. The fresh air makeup can be adjusted for 15, 35,
50 and 75 cubic meters per hour (CFM). The air flow has
been established at 60 Hz power, and a 2 1/2 inch T bar,
with 15 mm (0.6 inch) H
blow.
d. Air Sampling for Carbon Dioxide (CO
Loosen hex nuts and move the cover until the arrow on
the cover is aligned with the "atmosphere sampling port"
label. Tighten the hex nuts and attach a 3/8 hose to the
sampling port.
If the internal atmosphere content has reached an
unacceptable level, the operator may adjust the disc
opening to meet the required air flow volume to ventilate
the container.
4.4 CONNECT WATER-COOLED CONDENSER
The water-cooled condenser is used when cooling
water is available and heating the surrounding air is
objectionable, such as in a ship's hold. If water cooled
operation is desired, connect in accordance with the
following subparagraphs.
4.4.1 Water- -Cooled Condenser with Water Pres-
sure Switch
a. Connect the water supply line to the inlet side of con-
denser and the discharge line to the outlet side of the
condenser. (See Figure 2-5.)
b. Maintain a flow rate of 11 to 26 liters per minute (3 to 7
gallons per minute). The water pressure switch will
open to de-energize the condenser fan relay. The
condenser fan motor will stop and will remain stopped
until the water pressure switch closes.
c. To shift to air-cooled condenser operation,disconnect
the water supply and the discharge line to the water-
cooled condenser. The refrigeration unit will shift to
air-cooled condenser operation when the water pres-
sure switch closes.
4-2
NOTE
O external static above free
2
) Level
2
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