Unitary Ducted Split AC
17
Triple Evacuation Method
The triple evacuation method should only be used when vacuum pump is only capable of
pumping down to 28 inch of mercury vacuum, and system does not contain any liquid water. Refer
to Fig. 25 and proceed as follows:
1. Pump system down to 28 inch of mercury and allow pump to continue operating for an
additional 15 minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system and open until system pressure is 2
psig.
4. Close service valve and allow system to stand for 1 hour. During this time, dry nitrogen will
be able to diffuse throughout the system absorbing moisture.
5. Repeat this procedure as indicated by Fig. 25. System will then be free of any contaminants
and water vapor.
Final Tubing Check
IMPORTANT:
Check to be certain factory tubing on both indoor and outdoor unit has not shifted
during shipment. Ensure tubes are not rubbing against each other or any sheet metal. Pay close
attention to feeder tubes, makings sure wire ties on feeder tubes are secure and tight.
Refrigerant Charge Determination and Adjustment
Weight in Charge Method
The unit was pre-charged good for 25 ft application, if the line set longer than 25ft, please refer
to the following table for additional charge.
Table 10
Liquid line size (inch)
Additional charge for every additional foot (oz)
3/8
0.32
1/2
0.64
Superheat Method
Table 11
SYSTEM SUPERHEAT
Ambient Condenser
Inlet Temp(
°F
Dry
bulb)
Return Air Temperature(
°F
Dry bulb)
65
70
75
80
85
115
11
100
11
26
95
20
18
27
90
19
24
33
85
28
29
33
34
80
29
31
33
34
75
29
30
33
34
35
70
29
34
37
36
36
65
32
35
39
39
42
60
34
37
39
42
43
