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50
51
52
55
7
9
10
60
5
7
8
65
4
70
75
Outdoor
Dry
80
Bulb
85
Temp.
(F)
90
95
100
105
110
115
Using a digital psychrometer, measure the return air wet-bulb temperature at the unit just before the coil. Also measure the outdoor dry-bulb tem-
perature. Use these temperatures to locate the target superheat on the charging table. Do not attempt to charge the system if these conditions fall
outside of this charging table.
ADD refrigerant to DECREASE total superheat. REMOVE refrigerant to INCREASE total superheat. Always allow 10 to 15 minutes of operature
after any refrigerant or air flow change prior to determining the final superheat.
14.4
Weigh-In Method for Charging
Weigh-In Method can be used for the initial
installation, or anytime a system charge is being
replaced. Weigh-In Method can also be used
when power is not available to the equipment
site or operating conditions (indoor/outdoor
temperatures) are not in range to verify with the
subcooling charging method.
Calculating Charge Using the Weigh-In Method
STEP 1 - Measure in feet the distance between the
outdoor unit and the indoor unit and record on Line 1.
Include the entire length of the line from the service
valve to the IDU.
STEP 2 - Enter the charge multiplier (0.4 oz/ft). Each
linear foot of interconnecting tubing requires the
addition of 0.4 oz of refrigerant.
STEP 3 - Multiply the total length of refrigerant tubing
(Line 1) times the value on Step 2. Record the result
on Line 3 of the Worksheet.
STEP 4 - This is the amount of refrigerant to weigh-in
prior to opening the service valves.
18
Fixed Orifice Superheat Charging Table
53
54
55
56
57
58
59
11
12
14
15
17
18
20
9
10
12
13
15
16
18
6
8
10
11
13
14
16
5
7
8
10
11
13
5
6
7
9
4
6
Indoor Wet Bulb Temp (F)
60
61
62
63
64
65
66
21
23
24
26
27
29
30
19
21
22
24
25
27
28
17
18
19
21
22
24
25
14
16
17
18
19
21
22
10
12
14
16
18
19
21
7
9
10
11
12
14
16
4
6
7
9
10
13
14
4
6
8
10
11
4
6
8
6
4
1. Line length (ft)
2. Charge multiplier
3. Step 1 x Step 2
4. Refrigerant
67
68
69
70
71
72
73
30
31
27
28
27
31
24
25
27
28
30
31
22
24
26
28
29
31
32
18
19
21
23
25
26
28
16
18
20
21
23
24
26
13
14
16
18
20
22
24
10
13
14
16
18
20
22
8
10
12
13
16
18
20
6
7
9
11
13
15
18
4
7
9
11
13
16
6
9
12
14
______________
x ____ 0.4 ______
= _____________
= _____________
88-A5AC5001-1A-EN
74
75
76
77
78
29
31
33
28
29
30
31
32
25
27
28
30
31
23
25
26
28
29
21
23
25
27
29
20
22
24
26
28
18
21
23
26
28
16
19
21
24
26
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