LG LB-F4280HL / LB-F4280CL Service Manual ▷ View online
–26–
CAUTION
After the confirmation of the above conditions, prepare the wiring as follows:
1) Never fail to have an individual power specialized for the air conditioner. As for the method of wiring,
be guided by the circuit diagram pasted on the inside of control box cover.
2) Provide a circuit breaker switch between power source and the unit.
3) The screw which fasten the wiring in the casing of electrical fittings are liable to come loose from
vibrations to which the unit is subjected during the course of transportation. Check them and
make sure that they are all tightly fastened. (If they are loose, it could give rise to burn-out of the
wires.)
make sure that they are all tightly fastened. (If they are loose, it could give rise to burn-out of the
wires.)
4) Specification of power source
5) Confirm that electrical capacity is sufficient.
6) Be sure that the starting voltage is maintained at more than 90 percent of the rated voltage marked
on the name plate.
7) Confirm that the cable thickness is as specified in the power sources specification.
(Particularly note the relation between cable length and thickness.)
8) Never fail to equip a leakage breaker where it is wet or moist.
9) The following troubles would be caused by voltage drop-down.
• Vibration of a magnetic switch, damage on the contact point there of, fuse breaking, disturbance to the
normal function of a overload protection device.
• Proper starting power is not given to the compressor.
Teach the customer the operation and maintenance procedures, using the operation manual (air filter cleaning,
temperature control, etc.).
temperature control, etc.).
HAND OVER
2) Connection of power supply
1. Connect the power supply cord to the independent power supply.
• Circuit breaker is required.
2. Operate the unit for fifteen minutes or more.
3) Evaluation of the performance
1. Measure the temperature of the intake and discharge air.
2. Ensure the difference between the intake temperature and the discharge one is more than 8°C (Cooling) or
reversely (Heating).
3-way Valve
1. Pump down
• Procedure
(1) Confirm that both liquid side and gas side
valves are set to the open position.
– Remove the valve stem caps and confirm that
– Remove the valve stem caps and confirm that
the valve stems are in the raised position.
– Be sure to use a hexagonal wrench to operate
the valve stems.
(2) Operate the unit for 10 to 15 minutes.
(3) Stop operation and wait for 3 minutes, then
connect the charge set to the service port of
the 3-way valve.
– Connect the charge hose to the service port.
the 3-way valve.
– Connect the charge hose to the service port.
(4) Air purging of the charge hose.
– Open the low-pressure valve on the charge set
slightly to air purge from the charge hose.
(5) Set the liquid side valve to the closed
position.
(6) Operate the air conditioner in cooling mode
and stop it when the gaug e indicates
1kg/cm
1kg/cm
2
g.
(7) Immediately set the 3-way valve to the closed
position.
– Do this quickly so that the gauge ends up
– Do this quickly so that the gauge ends up
indicating 3 to 5kg/cm
2
g.
(8) Disconnect the charge set, and mount the 2-
way and 3-way valve’s stem nuts and the
service port nut.
– Use torque wrench to tighten the service port
service port nut.
– Use torque wrench to tighten the service port
nut to a torque of 1.8 kg.m.
– Be sure to check for gas leakage.
Lo
Closed
Purge the air
Outdoor unit
Indoor unit
Liquid side
Gas side
CLOSE
Open
3-Way
valve
valve
3-Way
valve
valve
CLOSE
–27–
1) Re-air purging
(Re-installation)
• Procedure
The air which contains moisture remaining in the
refrigeration cycle may cause a malfunction on
the compressor.
refrigeration cycle may cause a malfunction on
the compressor.
(1) Confirm that both the liquid side valve and the
gas side valve are set to the closed position.
(2) After connecting the piping, check the joints
for gas leakage with gas leak detector.
(3) Remove the service port nut, and connect the
gauge manifold and the vacuum pump to the
service port by the charge hose.
service port by the charge hose.
(4) Vacuum the indoor unit and the connecting
pipes until the pressure in them lowers to
below -76cmHg.
below -76cmHg.
(5) Disconnect the charge hose and fit the nut to
the service port.
(Tightening torque: 1.8kg.m)
(Tightening torque: 1.8kg.m)
(6) Remove the valve stem nuts, and fully open
the stems of the 2-way and 3-way valves with a
hexagon wrench.
hexagon wrench.
(7) Tighten the valve stem nuts of the 2-way valve
and 3-way valve.
Indoor unit
Outdoor unit
Liquid side
CLOSE
OPEN
Vaccum pump
Gas side
Closed
Closed
2-way
valve
3-way
valve
–28–
2) Balance refrigerant of the 3-way valve
(Gas leakage)
• Procedure
(1) Confirm that both the liquid side and gas side
valves are set to the back seat.
(2) Connect the charge set to the 3-way valve’s
port.
– Leave the valve on the charge set closed.
– Connect the charge hose to the service port.
– Leave the valve on the charge set closed.
– Connect the charge hose to the service port.
(3) Open the valve (Lo side) on the charge set
and discharge the refrigerant until the gauge
indicates 0 kg/cm
indicates 0 kg/cm
2
G.
– If there is no air in the refrigerant cycle (the
pressure when the air conditioner is not
running is higher than 1 kg/cm
running is higher than 1 kg/cm
2
G), discharge
the refrigerant until the gauge indicates 0.5 to 1
kg/cm
kg/cm
2
G. if this is the case, it will not be
necessary to apply a evacuatin.
– Discharge the refrigerant gradually; if it is
discharged too suddenly, the refrigeration oil
will also be discharged.
will also be discharged.
Lo
Open
Open
3-Way
valve
valve
3-Way
valve
valve
Gas side
CLOSE
OPEN
Outdoor unit
Liquid side
Indoor unit
–29–
Click on the first or last page to see other LB-F4280HL / LB-F4280CL service manuals if exist.