6--10
T-334
6.8 CONDENSER COIL
The condenser consists of a series of parallel copper
tubes expanded into copper fins. The condenser coil
must be cleaned with fresh water or steam so the air flow
is not restricted. To replace the coil, do the following:
WARNING
Do not open the condenser fan grille before
turning power OFF and disconnecting
power plug.
a. Using a refrigerant reclaim system, remove the refrig-
erant charge.
b. Remove the condenser coil guard.
c. Unsolder discharge line and remove the line to the
receiver or water-cooled condenser.
d. Remove coil mounting hardware and remove the coil.
e. Install replacement coil and solder connections.
f. Leak-check the coil connections per paragraph para-
graph 6.3.3 for standard piping and 6.4.3 for semi-
hermetic piping. Evacuate the unit then charge the
unit with refrigerant.
6.9 CONDENSER FAN AND MOTOR ASSEMBLY
WARNING
Do not open condenser fan grille before
turning power OFF and disconnecting
power plug.
The condenser fan rotates counter-clockwise (viewed
from front of unit), pulls air through the the condenser
coil, and discharges horizontally through the front of the
unit. To replace motor assembly:
a. Open condenser fan screen guard.
b. Loosen two square head set screws on fan. (Thread
sealer has been applied to set screws at installation.)
c. Disconnect wiring connector.
CAUTION
Take necessary steps (place plywood over
coil or use sling on motor) to prevent motor
from falling into condenser coil.
d. Remove motor mounting hardware and replace the
motor. It is recommended that new locknuts be used
when replacing motor.
e. Connect the wiring connector.
f. Install fan loosely on motor shaft (hub side in). DO
NOT USE FORCE. If necessary, tap the hub only, not
the hub nuts or bolts. Install venturi. Apply “Loctite H”
to fan set screws. Adjust fan within venturi so that the
outer edge of the fan is within 2.0 +/- 0.07 mm
(0.08” +/- 0.03”) from the outside of the orifice open-
ing. Spin fan by hand to check clearance.
g. Close and secure condenser fan screen guard.
6.10 WATER--COOLED CONDENSER CLEANING
The water-cooled condenser is of the shell and coil type
with water circulating through the cupro-nickel coil. The
refrigerant vapor is admitted to the shell side and is
condensed on the outer surface of the coil.
Rust, scale and slime on the water-cooling surfaces
inside of the coil interfere with the transfer of heat,
reduce system capacity, cause higher head pressures
and increase the load on the system.
By checking the leaving water temperature and the
actual condensing temperature, it can be determined if
the condenser coil is becoming dirty. A larger than
normal difference between leaving condensing water
temperature and actual condensing temperature,
coupled with a small difference in temperature of
entering and leaving condensing water, is an indication
of a dirty condensing coil.
To find the approximate condensing temperature, with
the unit running in the cooling mode, install a gauge 0 to
36.2 kg/cm
2
(0 to 500 psig) on the compressor
discharge service valve.
Example:
Discharge pressure is 10.3 kg/cm
2
(146.4 psig). Referring to Table 6--8 (R-134a pressure/
temperature chart), the 10.3 kg/cm
2
(146.4 psig) value
converts to 43C (110F).
If the water-cooled condenser is dirty, it may be cleaned
and de-scaled by the following procedure:
a. Turn unit off and disconnect main power.
b. Disconnect water pressure switch tubing by loosen-
ing the two flare nuts. Install one-quarter inch flare
cap on water-cooled condenser inlet tube (replaces
tubing flare nut). De-scale tubing if necessary.
What You Will Need:
1. Oakite Composition No. 22, available as a powder in
68 kg (150 lb) and 136 kg (300 lb) containers.
2. Oakite Composition No. 32, available as a liquid in
cases, each containing 3.785 liters (4 U.S. gallon)
bottles and also in carboys of 52.6 kg (116 lbs) net.
3. Fresh clean water.
4. Acid proof pump and containers or bottles with rubber
hose.
NOTE
When Oakite Compound No. 32 is being used
for the first time, the local Oakite Technical Ser-
vice representative should be called in for their
suggestions in planning the procedure. They
will advise the reader on how to do the work with
a minimum dismantling of equipment: how to
estimate the time and amount of compound
required; how to prepare the solution; how to
control and conclude the de-scaling operation
by rinsing and neutralizing equipment before
putting it back into service. Their knowledge of
metals, types of scale, water conditions and de-
scaling techniques will be highly useful.
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