Charge Checks; Superheat Determination; Expansion Valve System - Goodman Split System Condensing Units IO-101G Installation And Operating Instructions Manual

The recommended procedure for processing and charge
adjustment is as follows:
1. Connect vacuum pump to both base valve service
ports.
2. Evacuate tubing and evaporator through liquid and
suction base valve ports, to 500 microns or less for a
minimum of 30 minutes. Close valve to pump and
wait 15 minutes. Vacuum should not rise above 800
microns. If unable to obtain 500 micorns, or vacuum
rises above 800 microns over a 15 minute period,
discontinue evacuation, pressurize and check for
leaks. Repair any leaks found and repeat step 2.
3. Close valve to vacuum pump and stop pump. Break
vacuum by opening liquid and suction base valves.
Fully open base valves and remove pump lines.
Connect service gauges making sure lines are purged.
4. Set thermostat system switch to "COOL" and
temperature to highest setting. Close all disconnects.
5. Set thermostat to call for cooling. Check for operation
of indoor and outdoor fans. Allow for at least 10
minutes.
6. Check charge and adjust if necessary. Refer to
appropriate "Check Charge" section.

Charge Checks

Capillary Tube/Fixed Orifice System
1. Fully open both base valves.
2. Connect service gauge manifold to base-valve service
ports being sure to purge lines. Run system at least
10 minutes to allow pressure to stabilize.
3. Temporarily install thermometer on suction (large) line
near condensing unit. Be sure of good contact
between the thermometer and line. Wrap thermometer
with insulating material to assure accurate reading.
4. Refer to Table 2 for proper system superheat. Add
charge to lower superheat. Remove charge to raise
superheat.
5. Remove gauge lines carefully.
WARNING
ESCAPING LIQUID REFRIGERANT CAN CAUSE
BURNS.
SYSTEM SUPERHEAT
AMBIENT CONDENSER
INLET TEMPERATURE
°F DRYBULB
100
95
90
85
80
75
70
65
60
TABLE 2
IO-101G
RETURN AIR TEMPERATURE
( °F DRYBULB)
65 70 75 80
5
5 5
7 12
5 10 17
5 12 21
5 10 17 25
5 14 20 28
13 19 26 32
17 25 30 33

Superheat Determination

1. Read suction pressure. Using Table 3, determine
saturated suction temperature.
2. Read suction line temperature.
3. Use the following formula to determine superheat:
Superheat = Suction Line Temp. - Saturated Suction Temp.
SATURATED SUCTION PRESSURE (R-22)
SUCTION
PRESSURE PSIG
50
53
55
58
61
63
66
69
72
75
78
81

Expansion Valve System

1. Fully open both base valves.
2. Connect service gauge manifold to base-valve service
parts making sure lines are purged. Run system at
least 10 minutes to allow pressure to stabalize.
3. Temporarily install the thermometer to liquid (small)
line near condensing unit. Be sure that the contact
between thermometer and line is good. Wrap
thermometer with insulating material to ensure
accurate reading.
4. Referring to Table 4, adjust charge to obtain a
temperature 12-15°F below the saturated liquid
temperature.
Example:
If the Liquid Pressure is 260 PSIG then the Saturated
Temperature will be 120°F.
Temperature by subtracting 12-15°F. This will give you a
Liquid Line Temperature of 105° - 108°F.
SATURATED LIQUID TEMPERATURE
LIQUID PRESSURE
(PSIG)
200
85 210
220
5
230
5
240
18
250
20
260
26 270
280
29
290
32
300
35
37
5
SATURATED SUCTION
TEMPERATURE °F
26
28
30
32
34
36
38
40
42
44
46
48
TABLE 3
Adjust the Saturated
SATURATED
TEMPERATURE °F
102
105
108
111
114
117
120
123
126
128
131
TABLE 4
06/04