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Evacuating the System
EVACUATING
LINE SET AND INDOOR COIL
CONNECT GAUGE SET
1
NOTE
Remove cores from service valves (if not al-
ready done).
A
Connect low side of manifold gauge set
with 1/4 SAE in−line tee to vapor line
service valve
B
Connect high side of manifold gauge
set to liquid line service valve
C
Connect micron
connector on the 1/4 SAE in−line tee.
D
Connect 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.
HFC−410A
NITROGEN
2
EVACUATE 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
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
The 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.
C
When 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.
D
Shut 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.
E
Reconnect 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.
F
When 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.
S
Shut off HFC−410A cylinder.
S
Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with
core tool while maintaining a positive system pressure.
S
Replace the stem caps and secure finger tight, then tighten an additional one−sixth (1/6) of a turn as
illustrated.
506510−01
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OUTDOOR
UNIT
VAPOR
gauge available
SERVICE
VALVE
LIQUID LINE
SERVICE VALVE
VACUUM PUMP
search engine
A34000 1/4 SAE TEE WITH
SWIVEL COUPLER
A
500
C
B
D
Page 18
MANIFOLD
GAUGE SET
LOW
MICRON
GAUGE
TO VAPOR
SERVICE VALVE
TO LIQUID LINE
SERVICE VALVE
RECOMMEND
MINIMUM 3/8" HOSE
11 12
10
9
8
7
6
HIGH
1/6 TURN
1
2
3
4
5
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