Carrier 69NT40-541-001, Operation And Service

Page: 106 / 156

T-316 7–18
a. Using a refrigerant reclaim system, remove the refrigerant 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.
Leak-check the coil connections per Section 7.5 . Evacuate the unit per Section 7.6 then charge the unit with
refrigerant per Section 7.7 .
7.11 CONDENSER FAN AND MOTOR ASSEMBLY
WARNING
!
Do not open condenser fan grille before turning power OFF and disconnecting power plug.
The condenser fan rotates counterclockwise (viewed from front of unit), pulls air through 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.)
Disconnect wiring from motor junction box.
CAUTION
!
Take necessary steps (place plywood over coil or use sling on motor) to prevent motor from
falling into condenser coil.
c. Remove motor mounting hardware and replace the motor. It is recommended that new locknuts be used
when replacing motor. Connect wiring per wiring diagram.
d. 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 projects 3.2 to 6.4 mm (3/16” 1/16”) back from edge of the venturi. Spin fan by hand to
check clearance.
e. Close and secure condenser fan screen guard.
Apply power to unit and check fan rotation. If fan motor rotates backward, reverse wire numbers 5 and 8.
7.12 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 sys-
tem 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 con-
denser 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/cm² (0 to 500 psig) on the compressor discharge service valve.
Example: Discharge pressure is 10.3 kg/cm² (146.4 psig). Referring to Table 7–8 (R-134a pressure/ temperature
chart), the 10.3 kg/cm² (146.4 psig) value converts to 43°C (110°F).