16
any air moisture and noncodensables from the
refrigeration circuit. After 50 seconds has passed
tighten the hose on the low pressure gauge. The
sweep is now complete.
Next step, open the 2 way valve all the way then
the 3 way valve all the way and check for leaks.
4). Next step, Start the unit in the cooling mode
and check the pressure (remember the pressure
you recorded?) The unit is going to be low on
refrigerant from the sweeping process, add
refrigerant as needed from the refrigerant
container in the liquid state to achieve the
operating pressure that you recorded. The process
is now complete.
Check the flare connections for gas leakage.
5). Discharge the refrigerant.
Close the valve on the charging cylinder and
discharge the refrigerant by loosening the flare
nut on the 2-way valve approximately 45’ until
the gauge indicates 0.3Mpa(43.5Psi) to 0.5
Mpa(72.5Psi).
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 operate
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 18N.m.
Be sure to check the gas leakage.
6.7 Evacuation after servicing the outdoor
unit refrigeration circuit.
1. Evacuation of the complete refrigeration
circuit, Indoor and outdoor unit.
Procedure:
1). Confirm that both the 2-way and 3-way
valves are set to the opened position.
2). Connect the vacuum pump to 3-way valve’s
service port.
3). Evacuation for approximately one hour.
Confirm that the compound meter indicates
-0.1Mpa(14.5Psi), 500 Microns / 29.9 in,hg.
4). 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).
5). Disconnect the charge hose from the
vacuum pump.
2. Refrigerant charging
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 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). 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
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