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)
6.Refer to Table 4. Find outdoor temperature and evaporator entering air
7.Refer to Table 5. Find superheat temperature located in item 6 and suction pressure. At this intersection, note suction line temperature.
8.If unit has a higher suction line temperature than charted temperature, add refrigerant until charted temperature is reached.
9.If unit has a lower suction line temperature than charted temperature, reclaim refrigerant until charted temperature is reached.
10.When adding refrigerant, charge in liquid form into suction service port using a
11.If outdoor air temperature or pressure at suction valve changes, charge to new suction line temperature indicated on chart.
XIII. FINAL CHECKS
IMPORTANT: Before leaving job, be sure to do the following:
1.Ensure that all wiring and tubing is secure in unit before adding panels and covers. Securely fasten all panels and covers.
2.Tighten service valve stem caps to
3.Leave User’s Manual with owner. Explain system operation and periodic maintenance requirements outlined in manual.
4.Fill out Dealer Installation Checklist and place in customer file.
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equip- ment failure, periodic maintenance must be performed on this equipment.
Frequency of maintenance may vary depending upon geographic areas, such as coastal applications. See Users Manual for informa- tion.
