3.Inspect all factory− and field−installed wiring for loose connections.
4.Open the high side manifold gauge valve and weigh in liquid refrigerant. Use figure 20 to calculate the correct weigh−in charge.
5.Close manifold gauge valves.
6.Monitor the system to determine the amount of moisture remaining in the oil. It may be necessary to replace the bi−flow filter drier several times to achieve the required dryness level. If system dryness is not verified, the compressor will fail in the future.
7.Continue to Optimizing System Refrigerant Charge on page 25 to optimize the system charge using subcooling method.
MANIFOLD GAUGE SET
GAUGE SET
NOTE Refrigerant
LOW
HIGH
CONNECTIONS FOR OPTIMIZING SYSTEM CHARGE
tank should be turned right−side−up to deliver vapor during charge optimizing procedure.
B
| HFC−410A |
REFRIGERANT |
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TANK | A |
CHARGE IN | |
LIQUID PHASE |
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DIGITAL SCALE
TO LIQUID
LINE SERVICEVALVE C
TRUE SUCTION PORT
CONNECTION 
TEMPERATURE
SENSOR
(LIQUID LINE)
D
AClose manifold gauge set valves and connect the center hose to a cylinder of HFC−410A. Set for liquid phase charging.
BConnect the manifold gauge set’s low pressure side to the true suction port.
CConnect the manifold gauge set’s high pressure side to the liquid line service port.
DPosition temperature sensor on liquid line near liquid line service port (use only for subcooling method).
NOTE
the line set is not shown connected to service valves.
Figure 19. Typical Gauge Set Connections for Initial Weight−in Charge or Optimizing System Charge
CALCULATING SYSTEM CHARGE FOR OUTDOOR UNIT VOID OF CHARGE
If the system is void of refrigerant, first, locate and repair any leaks and then weigh in the refrigerant charge into the unit. To calculate the total refriger- ant charge:
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Amount specified on | Adjust amount. for variation in line set | match indoor air handler or coil | Total Charge | ||||||||
| nameplate | length listed on line set length table below. | listed in table 5. |
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Refrigerant Charge per Line Set Length
LIQUID LINE SET DIAMETER
3/8" (9.5 MM)
OUNCES PER 5 FEET (GRAMS PER 1.5 METERS) ADJUST FROM 15 FEET (4.6 METERS) LINE SET*
3 OUNCE PER 5’ (85 GRAMS PER 1.5 M)
*If line length is greater than 15 feet (4.6 meters), add this amount. If line length |
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is less than 15 feet (4.6 meters), subtract this amount. |
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NOTE | emperature |
of the liquid line or when pressure drop is equal to or greater than 20 psig. |
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NOTE . Go to actual nameplate on outdoor unit for charge information. |
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Figure 20. Using HFC−410A Weigh In Method
506728−01 | Page 24 |