TABLE 3—REQUIRED LIQUID-LINE TEMPERATURE (°F)
LIQUID |
|
| REQUIRED SUBCOOLING |
|
| ||
PRESSURE AT |
|
| TEMPERATURE |
|
| ||
SERVICE VALVE |
|
|
| (°F) |
|
| |
(PSIG) | 8 | 10 | 12 |
| 14 | 16 | 18 |
189 | 58 | 56 | 54 |
| 52 | 50 | 48 |
195 | 60 | 58 | 56 |
| 54 | 52 | 50 |
202 | 62 | 60 | 58 |
| 56 | 54 | 52 |
208 | 64 | 62 | 60 |
| 58 | 56 | 54 |
215 | 66 | 64 | 62 |
| 60 | 58 | 56 |
222 | 68 | 66 | 64 |
| 62 | 60 | 58 |
229 | 70 | 68 | 66 |
| 64 | 62 | 60 |
236 | 72 | 70 | 68 |
| 66 | 64 | 62 |
243 | 74 | 72 | 70 |
| 68 | 66 | 64 |
251 | 76 | 74 | 72 |
| 70 | 68 | 66 |
259 | 78 | 76 | 74 |
| 72 | 70 | 68 |
266 | 80 | 78 | 76 |
| 74 | 72 | 70 |
274 | 82 | 80 | 78 |
| 76 | 74 | 72 |
283 | 84 | 82 | 80 |
| 78 | 76 | 74 |
291 | 86 | 84 | 82 |
| 80 | 78 | 76 |
299 | 88 | 86 | 84 |
| 82 | 80 | 78 |
308 | 90 | 88 | 86 |
| 84 | 82 | 80 |
317 | 92 | 90 | 88 |
| 86 | 84 | 82 |
326 | 94 | 92 | 90 |
| 88 | 86 | 84 |
335 | 96 | 94 | 92 |
| 90 | 88 | 86 |
345 | 98 | 96 | 94 |
| 92 | 90 | 88 |
354 | 100 | 98 | 96 |
| 94 | 92 | 90 |
364 | 102 | 100 | 98 |
| 96 | 94 | 92 |
374 | 104 | 102 | 100 |
| 98 | 96 | 94 |
384 | 106 | 104 | 102 |
| 100 | 98 | 96 |
395 | 108 | 106 | 104 |
| 102 | 100 | 98 |
406 | 110 | 108 | 106 |
| 104 | 102 | 100 |
416 | 112 | 110 | 108 |
| 106 | 104 | 102 |
427 | 114 | 112 | 110 |
| 108 | 106 | 104 |
439 | 116 | 114 | 112 |
| 110 | 108 | 106 |
450 | 118 | 116 | 114 |
| 112 | 110 | 108 |
462 | 120 | 118 | 116 |
| 114 | 112 | 110 |
474 | 122 | 120 | 118 |
| 116 | 114 | 112 |
486 | 124 | 122 | 120 |
| 118 | 116 | 114 |
499 | 126 | 124 | 122 |
| 120 | 118 | 116 |
511 | 128 | 126 | 124 |
| 122 | 120 | 118 |
|
|
|
|
|
|
|
|
EXAMPLE:
To calculate additional charge requried for a
25 ft - 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge.
B. COOLING ONLY PROCEDURE
UNITS WITH COOLING MODE PURON® TXV
Units installed with cooling mode TXV require charging by the subcooling method.
1.Operate unit a minimum of 10 minutes before checking charge.
2.Measure liquid service valve pressure by attaching an accurate gage to service port.
3.Measure liquid line temperature by attaching an accurate thermistor type or electronic thermometer to liquid line near outdoor coil.
4.Refer to unit rating plate for required subcooling tempera- ture.
5.Refer to Table 3. Find the point where required subcooling temperature intersects measured liquid service valve pres- sure.
6.To obtain required subcooling temperature at a specific liquid line pressure, add refrigerant if liquid line tempera- ture is higher than indicated or reclaim refrigerant if temperature is lower. Allow a tolerance of ± 3°F.
UNITS WITH INDOOR PISTONS
Units installed with indoor pistons require charging by the super- heat method.
The following procedure is valid when indoor airflow is within ± 21 percent of its rated CFM.
1.Operate unit a minimum of 10 minutes before checking charge.
2.Measure suction pressure by attaching an accurate gage to suction valve service port.
3.Measure suction temperature by attaching an accurate thermistor type or electronic thermometer to suction line at service valve.
4.Measure outdoor air
5.Measure indoor air (entering indoor coil)