5–3 T-362
Figure 5.2 Upper Fresh Air Make Up Flow Chart
5.3.2 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 (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 Lower Fresh Air Makeup
NOTE
In order to prevent inaccurate display readings on units equipped with a VPS, ensure that the rack and
pinion drive of the VPS is not disrupted when adjusting the air makeup vent.
NOTE
Do not loosen the hex nut beyond its stop. Doing so may cause inaccurate display readings and errors
in DataCORDER reports.
Similar to the Upper Fresh Air Makeup vent, two slots and a stop are designed into the Lower Fresh Air slide for air
flow adjustments. The first slot allows for a 0 to 25% air flow; the second slot allows for a 25 to 100% air flow. To
adjust the percentage of air flow, loosen the hex nut and rotate the disc until the desired percentage of air flow
matches with the arrow. Tighten the hex nut. To clear the gap between the slots, loosen the hex nut until the disc
clears the stop.
On some models the air slide is supplied with two adjustable air control discs. 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, adjust each disc to the required air flow, then tighten the hex nut.
NOTE
The main air slide is in the fully closed position during reduced air flow operation when equipped with
air control discs.
c. Air Sampling for Carbon Dioxide (CO
2
) Level
Loosen the 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.
0
50
100
150
200
250
0 102030405060708090
100
TBAR
11/2”
TBAR
25/8”
TBAR 3”
A
IR
FLOW
(CMH)
50HZ
PERCENT OPEN
0
50
100
150
200
250
300
0 102030405060708090
100
TBAR
11/2”
TBAR
25/8”
TBAR 3”
AIR
FLOW
(CMH)
60HZ
PERCENT OPEN