T-334
4--2
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--2 gives air exchange
values for an empty container. Higher values can be
expected for a fully loaded container.
AIR
FLOW
(CMH)
1-1/2”
PERCENT OPEN
50HZ
T-BAR
2-5/8”
3”
T-BAR
T-BAR
0
90
60
30
120
150
180
210
240
0
10 20 30 40 50 60 70 80 90 100
AIR
FLOW
(CMH)
1-1/2”
PERCENT OPEN
T-BAR
2-5/8”
3”
T-BAR
T-BAR
60HZ
0
10 20 30 40 50 60 70 80 90 100
0
40
80
120
160
200
240
280
Figure 4--2 Make Up Air Flow Chart
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
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
adjustable air control disks. The fresh air makeup can be
adjusted for 15, 35, 50 or 75 cubic meters per hour
(CMH). The air flow has been established at 60 Hz
power and 2-1/2 inch T bar and with 15 mm (0.6 inch)
H
2
O external static above free blow.
Loosen the hex nut and adjust each disk to the required
air flow and tighten hex nut.
NOTE
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 (CMH). 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
2
O external static above free
blow.
NOTE
The main air slide is in the fully closed position
during reduced air flow operation.
d. Air Sampling for Carbon Dioxide (CO
2
) Level
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 in. 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.
4.3.3 Fresh Air Position Sensor
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:
Trip start
On every power cycle
Midnight
Manual change greater than 5 CMH (3 CFM) and
remains in that position for 4 minutes
NOTE
The user has 4 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 4-minute 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 DataCORD-
ER.
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