T-359 5–25.3.1 Upper Fresh Air Makeup VentTwo slots and a stop are designed into the Upper Fresh Air disc for air flow adjustments. The first slot allows for a 0to 30% air flow; the second slot allows for a 30 to 100% air flow. To adjust the percentage of air flow, loosen thewing 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 5.1 gives air exchange values for an empty container. Higher values can be expected for a fully loaded con-tainer.Figure 5.1 Upper Fresh Air Make Up Flow Chart5.3.2 Vent Position SensorThe VPS allows the user to determine the position of the fresh air vent via Function Code 45. This function code isaccessible via the Code Select key.The vent position will display for 30 seconds whenever motion corresponding to 5 CMH (3 CFM) or greater isdetected. It will scroll in intervals of 5 CMH (3 CFM). Scrolling to Function Code 45 will display the Fresh Air VentPosition.The position of the vent will be recorded in the DataCORDER whenever the unit is running under AC power andany of the following:• Trip start• On every power cycle• Midnight• Manual changes greater than 5 CMH (3 CFM)• Remaining in the new position for at least 4 minutesNOTEThe user has four minutes to make necessary adjustments to the vent setting. This time calculationbegins on the initial movement of the sensor. The vent can be moved to any position within the fourminutes. On completion of the first four minutes, the vent is required to remain stable for the next fourminutes. If vent position changes are detected during the four-minute stability period, an alarm will begenerated. This provides the user with the ability to change the vent setting without generating multi-ple events in the DataCORDER.0501001502002500 10 20 30 40 50 60 70 80 90 100TBAR1 1/2”TBAR2 5/8”TBAR 3”AIRFLOW(CMH) 50HZPERCENT OPEN0501001502002503000 10 20 30 40 50 60 70 80 90 100TBAR1 1/2”TBAR2 5/8”TBAR 3”AIRFLOW(CMH) 60HZPERCENT OPEN
