3 Servicing
Cycle components
SMGB0120 rev.0 - 11/2017
67
3
3.3.3
Recovering the refrigerant
Recovering the refrigerant by “Pump-down” procedure
The steps to follow for recovering the refrigerant by “pump-down” are described below:
1
Collect all refrigerant into the condenser:
a.
Circulate the chilled water sufficiently through the water cooler, and operate the unit for 10 minutes. Check to
ensure that the oil level is maintained at a stable condition.
b.
Stop the unit and completely close the liquid stop valve.
c.
Operate the water chiller after circulating water through the water cooler.
d.
Stop the unit when the low pressure reaches at approximately 0.05 MPa. Do not operate at a pressure lower than
0.05 MPa. If operated, it will cause a damage to the compressor.
e.
Wait for several minutes. If the low pressure increases up to 0.45 to 0.5 MPa, repeat the above steps 4 and 5 four
or five times.
f.
Turn OFF the power supply of the unit and wait 15 min until hot parts become cool.
g.
After these works above, almost all refrigerant is collected in the condenser.
h.
Recover the rest of refrigerant from the water cooler and the compressor connecting a hose to the check joint and
a vacuum and collect the rest of refrigerant into a tank.
With a vacuum pump
a.
Completely close the stop valve.
b.
Connect the gauge manifold using charging hoses with a vacuum pump or a Nitrogen cylinder to the check joints
of the refrigerant line.
c.
Check for any leakage at the flare nuts connections by using nitrogen gas to increase the pressure at 4.15 MPa.
d.
Operate the vacuum pump for 1 or 2 hours, or until the pressure decreases lower than a pressure of 756 mmHg
in vacuum.
e.
Take note of the quantity of refrigerant charged into the tank in order to provide the same quantity when charging
the circuit.
3.3.4
Replacement of the condenser
1
Unscrew the 2 flare nuts of refrigerant outlet
pipes.
Condenser
Distributor
Inlet pipe flange
4 Screws
Outlet pipe
2 flare nuts
2
Unscrew the 4 screw of the 4 refrigerant inlet
pipe flange.
Bolt
Spring washer
Flange plate
