Lennox LNIV2610 Service Manual page 9

2. Air purging by refrigerant
Procedure:
1. Confi rm that both the 2-way and 3-way valves are set to the
"closed" position.
2. Connect the charge set and a charging cylinder to the service
port of the 3-way valve.
3. Air purging. Open the valves on the charging cylinder and the
charge set. Purge the air by loosening the fl are nut on the
2-way valve approximately 45° for 3 seconds then closing it
for 1 minute; repeat 3 times. After purging the air, use a torque
wrench to tighten the fl are nut on the 2-way valve.
4. Check for gas leakage. Check the fl are connections for gas
leakage.
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5. Discharge the refrigerant. Close the valve on the charging
cylinder and discharge the refrigerant by loosening the fl are nut
on the 2-way valve approximately 45° until the gauge indicates
0.3 to 0.5 Mpa.
6. Disconnect the charge set and the charging cylinder, and set
the 2-way and 3-way valves to the "open" position. Be sure to
use a hexagonal wrench to open the valve stems.
7. Mount the valve stems nuts and the service port cap. Be sure
to use a torque wrench to tighten the service port cap to a
torque of 18Nm. Be sure to check for gas leakage.
3. Adding refrigerant if the pipe length >5m
Electronic scale
Procedure:
1. Connect the charge hose to the charging cylinder, open the
2-way valve and the 3-way valve. Connect the charge hose
which you disconnected from the vacuum pump to the valve at
the bottom of the cylinder. If the refrigerant is R410A, make the
cylinder bottom-up to ensure the liquid charge.
2. Purge the air from the charge hose. Open the valve at the
bottom of the cylinder and press the check valve on the charge
set to purge the air (be careful of the liquid refrigerant).
3. Put the charging cylinder onto the electronic scale and record
the weight.
4. Operate the air conditioner in the cooling mode.
5. Open the valves (Low side) on the charge set and charge the
system with liquid refrigerant.
6. When the electronic scale displays the proper weight (refer to
the table), disconnect the charge hose from the 3-way valve's
service port immediately and turn off the air conditioner before
disconnecting the hose.
7. Mount the valve stem caps and the service port. Use a torque
wrench to tighten the service port cap to a torque of 18Nm. Be
sure to check for gas leakage.
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