Evacuating the System
EVACUATING
LINE SET AND INDOOR COIL
CONNECT GAUGE SET
1NOTEready done)Remove. cores from service valves (if not al-
MANIFOLD
GAUGE SET
LOWHIGH
AConnect low side of manifold gauge set with 1/4 SAE in−line tee to vapor line service valve
BConnect high side of manifold gauge set to liquid line service valve
CConnect micron gauge available connector on the 1/4 SAE in−line tee.
DConnect the vacuum pump (with vacuum gauge) to the center port of the manifold gauge set. The center port line will be used later for both the HFC−410A and nitrogen containers.
OUTDOOR
UNIT
A
VAPOR
SERVICE
VALVE
A34000 1/4 SAE TEE WITH
SWIVEL COUPLER
500
C
MICRON
GAUGE
TO VAPOR
SERVICE VALVE
LIQUID LINE
SERVICE VALVE 
HFC−410A
B
VACUUM PUMP
TO LIQUID LINE
SERVICE VALVE
D
NITROGEN | RECOMMEND | |
MINIMUM 3/8" HOSE | ||
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2EVACUATE THE SYSTEM
AOpen both manifold valves and start the vacuum pump.
BEvacuate the line set and indoor unit to an absolute pressure of 23,000 microns (29.01 inches of mercury).
NOTE During the early stages of evacuation, it is desirable to close the manifold gauge valve at least once. A rapid rise in pressure indicates a relatively large leak. If this occurs, repeat the leak testing procedure.
NOTE he term absolute pressure means the total actual pressure within a given volume or system, above the absolute zero of pressure. Absolute pressure in a vacuum is equal to atmospheric pressure minus vacuum pressure.
CWhen the absolute pressure reaches 23,000 microns (29.01 inches of mercury), close the manifold gauge valves, turn off the vacuum pump and disconnect the manifold gauge center port hose from vacuum pump. Attach the manifold center port hose to a dry nitrogen cylinder with pressure regulator set to 150 psig (1034 kPa) and purge the hose. Open the manifold gauge valves to break the vacuum in the line set and indoor unit. Close the manifold gauge valves.
DShut off the dry nitrogen cylinder and remove the manifold gauge hose from the cylinder. Open the manifold gauge valves to release the dry nitrogen from the line set and indoor unit.
EReconnect the manifold gauge to the vacuum pump, turn the pump on, and continue to evacuate the line set and indoor unit until the absolute pressure does not rise above 500 microns (29.9 inches of mercury) within a 20−minute period after shutting off the vacuum pump and closing the manifold gauge valves.
FWhen the absolute pressure requirement above has been met, disconnect the manifold hose from the vacuum pump and connect it to an upright cylinder of HFC−410A refrigerant. Open the manifold gauge valve 1 to 2 psig in order to release the vacuum in the line set and indoor unit.
G Perform the following:
S | Close manifold gauge valves. | 11 | 12 | 1 | ||
S | Shut off HFC−410A cylinder. | |||||
10 |
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S | Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with |
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9 |
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| core tool while maintaining a positive system pressure. |
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S | Replace the stem caps and secure finger tight, then tighten an additional one−sixth (1/6) of a turn as | 8 |
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| illustrated. | 7 | 6 | 5 | ||
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