Evacuating Line Set and Indoor Coil
Evacuating the system of non−condensables is critical for proper operation of the unit. Non−condensables are defined as any gas that will not condense under temperatures and pressures present during operation of an air conditioning system. Non−condensables and water suction combine with refrigerant to produce substances that corrode copper piping and compressor parts.
CONNECT GAUGE SET
1NOTEA Connect 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.
NITROGEN
OUTDOOR
UNIT
HFC−410A
VACUUM PUMP
LOW HIGH
| A34000 1/4 SAE TEE WITH |
| MANIFOLD |
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| GAUGE SET | |
| SWIVEL COUPLER |
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A |
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| 500 |
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| C | MICRON | TO VAPOR |
| SERVICE VALVE | ||
| GAUGE | ||
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B | TO LIQUID LINE | |
SERVICE VALVE | ||
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RECOMMEND
MINIMUM 3/8" HOSE
D
2EVACUATE THE SYSTEM
A Open both manifold valves and start the vacuum pump.
B Evacuate the line set and indoor unit to an absolute pressure of 23,000 microns (29.01 inches of mercury).
NOTE | ure |
indicates a relatively large leak. If this occurs, repeat the leak testing procedure. | |
NOTE | 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), perform the following:
S S S S S
Close manifold gauge valves
Close valve on vacuum pump and turn off vacuum pump
Disconnect manifold gauge center port hose from vacuum pump
Attach manifold center port hose to a dry nitrogen cylinder with pressure regulator set to 150 psig (1034 kPa) and purge the hose.
Open manifold gauge valves to break the vacuum in the line set and indoor unit.
SClose 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. |
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S | Shut off HFC−410A cylinder. | |||||
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Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with core | 9 |
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| tool while maintaining a positive system pressure. | 8 |
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S | Replace stem caps and secure finger tight, then tighten an additional one−sixth (1/6) of a turn as illustrated. | 7 | 6 | 5 | ||
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Figure 14. Evacuating Line Set and Indoor Coil
506728−01 | Page 18 |