Carrier 69NT40-541-505, Руководство по эксплуатации и обслуживанию, Страница: 103 / 143

7–11 T-368
d. Set nitrogen pressure regulator at 26.4kg/cm
2
(375psig) with bleed-off valve closed.
e. Close valve on cylinder and open bleed-off valve.
f. Open cylinder valve. Slowly close bleed-off valve
to increase pressure on switch. The switch
should open at a static pressure up to 25kg/cm
2
(350 psig). If a light is used, light will go out. If an
ohmmeter is used, the meter will indicate open
circuit.
g. Slowly open bleed-off valve to decrease the
pressure. The switch should close at 18kg/cm
2
(250 psig).
7.9.2 Replacing the High Pressure Switch
a. Turn unit start-stop switch OFF. Frontseat both
suction and discharge service valves to isolate
compressor. Remove the refrigerant from the
compressor.
b. Disconnect wiring from defective switch. The
high pressure switch is located on the center
head and is removed by turning counterclock-
wise (see
Figure 3.3 ).
c. Install a new high pressure switch after verifying
switch settings (refer to Section 7.9.1 ).
d. Evacuate and dehydrate the compressor per
Section 7.6 .
7.10 CONDENSER COIL
The condenser coil consists of a series of parallel cop-
per tubes expanded into copper fins and formed into a
“C“ shape with the fourth side of the square formed by
the side support bracket.
7.10.1 Condenser Coil Cleaning
To ensure optimal efficiency of the unit the condenser
coil must be clean. The condenser coil should be
cleaned at least once a year, but more frequent clean-
ing may be required depending on operating condi-
tions. The coil is cleaned with fresh water sprayed in
the reverse direction of the air flow to remove any
debris from the coil. A high pressure washer is not
required, mains water pressure is sufficient. To clean
the condenser coil perform the following procedure:
WARNING
!
Do not remove the condenser fan grille
before turning power OFF and discon-
necting the power plug.
a. Make sure the unit is powered off and the plug is
disconnected.
b. Remove the condenser fan grille.
c. Starting from the top of the coil, use a water
hose with a nozzle to wash the coil from the
inside out.
d. Systematically wash across the inside top face
of the coil until the water runs clean.
e. Wash down the center section, and then through
the bottom of the coil, continue washing until the
water runs clear.
f. After the coil is clean, rinse the condenser fan to
remove any dirt build up from the blades.
g. Replace the condenser fan grille ensuring that it
is centered around the fan.
7.10.2 Condenser Coil Removal
a. Using a refrigerant reclaim system remove the
refrigerant charge.
WARNING
!
Do not remove the condenser fan grille
before turning power OFF and discon-
necting the power plug.
b. Remove the condenser fan grille, retain all bolts
and washers for reuse.
c. Remove the condenser fan.
d. Remove the infill panels to the left and right of
the condenser fan shroud.
e. Remove the condenser fan shroud.
f. Unplug the condenser fan motor.
g. Remove and retain sufficient putty from around
the motor wire harness to allow the harness to
be slid back through the side support bracket.
h. Cut the top and bottom drain lines midway
between the side support bracket and the first
cable tie, approx 150mm (6”) from the side sup-
port bracket.
i. Remove and retain sufficient putty from around
the drain lines to allow the tubes to be slid back
through the side support bracket.
j. Remove filter drier.
k. Unbraze the inlet connection to coil.
l. Remove the cushion clamps securing the liquid
line to the top and bottom receiver brackets,
retain all clamps and securing hardware.
m. Place a support under the condenser coil before
releasing the coil from the frame.
n. Remove the lower mounting bracket bolts from
the inside of the coil.
o. Remove the top mounting bracket bolts and
grille extension mount from inside the coil.
p. Remove the side support bracket mounting
bolts.
q. Slide the condenser assembly with receiver out
of the unit.
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