CHARGING INSTRUCTIONS
PRESSURE SERVICE PORTS
High and low pressure service ports are installed on all units so that the system operating pressures can be observed. Pressure tables can be found later in the manual covering all models. It is imperative to match the correct pressure table to the unit by model number.
SYSTEM START-UP (INDOOR UNITS WITHOUT EXPANSION VALVES)
1.Close disconnect switch(es) and set the thermostat to cool and the temperature to the highest setting.
2.Check for proper airflow across the indoor coil by referring to indoor unit installation.
3.Connect the service gauges and allow the unit to run for at least 10 minutes or until pressures are stable. Check pressures to the system pressure table attached to the outdoor unit service panel. For optimum system performance, go to Step 4.
4.Install a thermometer on the suction line approximately 6" to 10" from the compressor. Optimum system performance will occur with a refrigerant charge resulting in a suction line superheat as determined from the following calculations.
A.Measure outdoor air dry bulb temperature
________ ºF
B.Measure indoor air wet bulb temperature
________ ºF
C. | Measure suction pressure | ______ PSIG |
D. | Measure suction line temperature | ________ ºF |
E. | Determine optimum system superheat |
|
| from Table 9 using outdoor air dry bulb | |
(Step B) and indoor air wet bulb (Step A)
________ ºF
F.Determine saturated suction temperature
from suction pressure using Table 10 ________ ºF
G.Determine system superheat:
Suction line temperature (Step D) | ________ ºF |
-Saturated suction temperature (Step F)
-________ ºF
= System superheat
= ________ ºF
H.Adjust the system superheat (Step G) to the optimum system superheat (Step E) by adding charge to lower the superheat or removing charge to raise the superheat.
I.Check final system operating pressures to the system pressure tables as was done in Step 3.
TABLE 9
SYSTEM SUPERHEAT
Outdoor Ambient | Return Air Temperature | |||||
| F | Wet Bulb |
| |||
Temperature ( F |
|
| ||||
|
|
|
|
|
| |
Dry Bulb) | 59 |
| 63 | 67 |
| 71 |
|
|
| ||||
|
|
|
|
|
|
|
105 | 1 |
| 1 | 5 |
|
|
95 | 1 |
| 3 | (8) |
| 20 |
90 | 1 |
| 7 | 14 |
| 26 |
85 | 3 |
| 9 | 19 |
| 33 |
80 | 8 |
| 14 | 25 |
| 39 |
75 | 10 |
| 20 | 30 |
| 42 |
|
|
|
|
|
|
|
TABLE 10
SATURATED SUCTION TEMPERATURE R-22
| Saturated Suction |
Suction Pressure PSIG | Temperature ( F) |
|
|
50 | 26 |
53 | 28 |
55 | 30 |
|
|
58 | 32 |
61 | 34 |
63 | 36 |
|
|
65 | 38 |
67 | 39 |
70 | 41 |
|
|
73 | 43 |
76 | 45 |
79 | 47 |
|
|
82 | 49 |
86 | 51 |
|
|
