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Page 24
Service and Weigh In Refrigerant for Outdoor Units Delivered Void of Charge
The following procedures are only required if it has been determine that the new outdoor unit is void of charge. Skip to the
next section if refrigerant charge is present.
LEAK CHECK, REPAIR AND EVACUATE
If the outdoor unit is void of refrigerant, clean the system
using the procedure described below.
1. Leak check system using procedures provided on
page 16. Repair any leaks discovered during leak test.
2. Evacuate the system using procedure provided in
figure 13.
3. Use nitrogen to break the vacuum and install a new
filter drier in the system.
4. Evacuate the system again using procedure in figure
12.
CONNECT MANIFOLD GAUGE SET AND WEIGH IN
CHARGE
After the evacuation procedure, reconnect the manifold
gauge set as illustrated in figure 21.
NOTE − Temperature sensor illustrated in figure 21 is not
required for initial system weigh in charging.
1. Close manifold gauge set valves and connect the
center hose to a cylinder of HFC−410A. Set for liquid
phase charging.
2. Connect the manifold gauge set’s low pressure side to
the true suction port.
3. Connect the manifold gauge set’s high pressure side
to the liquid line service port.
4. Connect the center hose of the gauge set to a cylinder
of HFC−410A and purge the hose. Then, place the
cylinder upside down on a scale.
5. Check that fan rotates freely.
6. Inspect all factory− and field−installed wiring for loose
connections.
7. Open the high side manifold gauge valve and weigh in
liquid refrigerant. Use figure 20 in calculating the
correct weigh−in charge.
8. Close manifold gauge valves.
9. 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.
10. Continue to Optimizing System Refrigerant Charge
on page 26 to optimize the system charge using
subcooling method.
WEIGH−IN CHARGING
LIQUID LINE SET DIAMETER
OUNCES PER 5 FEET (G PER 1.5 M) ADJUST FROM 15 FEET
(4.6 M) LINE SET*
3/8" (9.5 MM)
3 OUNCE PER 5’ (85 G PER 1.5 M)
*If line length is greater than 15 ft. (4.6 m), add this amount. If line length is less than 15 ft. (4.6 m), subtract
this amount.
Refrigerant Charge per Line Set Length
NOTE Ċ The above nameplate is for illustration purposes only. Go to actual nameplate on outdoor unit for charge information.
NOTE Ċ Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the temperature
of the liquid line or when pressure drop is equal to or greater than 20 psig.
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
refrigerant charge:
Amount specified on
nameplate
Adjust amount. for variation in line set
length listed on line set length table below.
Additional charge specified per indoor
unit match listed on page 28.
Total Charge
+
+
=
Figure 20. Using HFC−410A Weigh In Method