Lower Fresh Air Makeup Vent; Figure 5.2 Upper Fresh Air Make Up Flow Chart - Carrier Transicold 69NT40-561-001 Operation And Service Manual

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 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 Lower Fresh Air Makeup
In order to prevent inaccurate display readings on units equipped with a Vent Position Sensor (VPS),
ensure that the rack and pinion drive of the VPS is not disrupted when adjusting the air makeup vent.
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.

Figure 5.2 Upper Fresh Air Make Up Flow Chart

AIR
FLOW
(CMH)
50HZ
250
200
150
100
50
0
0 10 20 30 40 50
PERCENT OPEN
AIR
FLOW
(CMH)
60HZ
300
250
200
150
100
50
0
0 10 20 30 40 50
PERCENT OPEN
NOTE
NOTE
5–3
TBAR
1 1/2"
TBAR
2 5/8"
TBAR 3"
60 70 80 90 100
TBAR
1 1/2"
TBAR
2 5/8"
TBAR 3"
60 70 80 90
100
T-340