31
•
Be sure to check for gas leaks.
12.6. Servicing Indoor Unit Refrigeration
Circuit
12.6.1. Collecting Refrigerant into Outdoor Unit
•
Confirm that both the two-way and three-way valves
are set to the opened position
•
Remove the valve stem caps and confirm that the valve
stems are in the opened position.
•
Be sure to use a hexagonal wrench to operate the
valve stems.
•
Connect the charge hose with the push pin of handle lo
to the three-way valves gas service port.
•
Air purging of the charge hose - Open the handle Lo
valve of the manifold valve slightly to purge air from the
charge hose for five seconds and then close it quickly.
•
Set the two-way valve to the close position.
•
Operate the air conditioner at the cooling cycle and
stop it when the gauge indicates 0.1MPa (14 psi).
•
Set the three-way valve to the closed position
immediately
•
Do this quickly so that the gauge ends up indicating 0.3
to 0.5Mpa (43 - 72 psi).
•
Disconnect the charge set, and tighten the two-way
and three-way valve’s stem nuts.
•
Use a torque wrench to tighten the three-way valves
service port cap to a torque of 18N.m.
•
Be sure to check for gas leakage.
12.6.2. Air Purging with Vacuum Pump
•
Completely tighten the flare nuts of the indoor and
outdoor units, confirm that both the two-way and three-
way valves are set to the closed position.
•
Connect the charge hose with the push pin of handle lo
to the three-way valves gas service port.
•
Connect the charge hose of handle hi connection to the
vacuum pump.
•
Fully open the handle Lo of the manifold valve.
•
Operate the vacuum pump to evacuate.
•
Make evacuation for 30 minutes and check whether the
compound meter indicates - 0.1Mpa (500 microns). If
the meter does not indicate - 0.1Mpa (500 microbars)
after pumping 30 minutes, it should be pumped 20
minutes more. If the pressure can’t achieve -0.1Mpa
(500 microbars) after pumping 50 minutes, please
check if there are some leakage points.
•
Fully close the handle Lo valve of the manifold valve
and stop the operation of the vacuum pump. Confirm
that the gauge needle does not move (approximately
five minutes after turning off the vacuum pump).
•
Turn the flare nut of the three-way valves about 45°
counterclockwise for six or seven seconds after the gas
coming out, then tighten the flare nut again. Make sure
the pressure display in the pressure indicator is a little
higher than the atmosphere pressure. Then remove the
charge hose from the three-way valve.
•
Fully open the two-way valve and three-way valve and
securely tighten the cap of the three-way
12.7. Evacuation after Servicing the Outdoor
Unit Refrigeration Circuit
12.7.1. Evacuation of the Complete Refrigeration
Circuit, Indoor and Outdoor Unit
•
Confirm that both the two-way and three-way valves
are set to the opened position.
•
Connect the vacuum pump to three-way valve’s service
port.
•
Evacuation for approximately one hour. Confirm that
the compound meter indicates - 0.1Mpa (500 Microns /
29.9 in. hg).
•
Close the valve (Low side) on the charge set, turn off
the vacuum pump, and confirm that the gauge needle
does not move (approximately 5 minutes after turning
off the vacuum pump).
•
Disconnect the charge hose from the vacuum pump.
12.7.2. Refrigerant Charging
•
Connect the charge hose to the charging cylinder, open
the two-way valve and the three-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 R-410A, make the cylinder
bottom up to ensure liquid charge.
•
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).
•
Put the charging cylinder onto the electronic scale and
record the weight.
•
Open the valves (Low side) on the charge set and
charge the system with liquid refrigerant. If the
system cannot be charge with the specified amount
of refrigerant, or can be charged with a little at a time
(approximately 150g each time) , operating the air
conditioner in the cooling cycle; however, one time is
not sufficient, wait approximately 1 minute and then
repeat the procedure.
•
When the electronic scale displays the proper weight,
disconnect the charge hose from the 3- way valve’s
service port immediately
•
If the system has been charged with liquid refrigerant
Summary of Contents for MWHA009S4
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