Goodman Mfg IO-101G Charge Checks Capillary Tube/Fixed Orifice System, Superheat Determination

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	RETURN AIR TEMPERATURE
INLET TEMPERATURE		( °F DRYBULB)
°F DRYBULB
	65	70	75	80	85
100				5	5
95			5	5	5
90			7	12	18
85		5	10	17	20
80		5	12	21	26
75	5	10	17	25	29
70	5	14	20	28	32
65	13	19	26	32	35
60	17	25	30	33	37

TABLE 2

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	SATURATED SUCTION
PRESSURE PSIG	TEMPERATURE °F
50	26
53	28
55	30
58	32
61	34
63	36
66	38
69	40
72	42
75	44
78	46
81	48

TABLE 3

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. Adjust the Saturated Temperature by subtracting 12-15°F. This will give you a Liquid Line Temperature of 105° - 108°F.

SATURATED LIQUID TEMPERATURE

LIQUID PRESSURE	SATURATED
(PSIG)	TEMPERATURE °F
200	102
210	105
220	108
230	111
240	114
250	117
260	120
270	123
280	126
290	128
300	131

TABLE 4

IO-101G 5 06/04