7–11
T-340
7.11 Condenser Fan and Motor Assembly
WARNING
!
Do not open the condenser fan grille before turning power OFF and disconnecting the power plug.
The condenser fan rotates counter-clockwise (viewed from front of unit), pulls air through the condenser coil, and
discharges horizontally through the front of the unit.
To replace the condenser fan motor assembly:
1. Open condenser fan screen guard.
2. Loosen two square head set screws on fan. (Thread sealer has been applied to set screws at installation.)
3. Disconnect wiring connector.
CAUTION
!
Take necessary steps (place plywood over coil or use sling on motor) to prevent motor from
falling into condenser coil.
4. Remove motor mounting hardware and replace the motor. It is recommended that new locknuts be used
when replacing motor.
5. Connect the wiring connector.
6. 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 opening. Spin
fan by hand to check clearance.
7. Close and secure condenser fan screen guard.
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/cm
2
(0 to 500 psig) on the compressor discharge service valve.
Example:
Discharge pressure is 10.3 kg/cm
2
(146.4 psig). See
(R-134a pressure/ temperature chart),
the 10.3 kg/cm
2
(146.4 psig) value converts to 43°C (110°F).
If the water-cooled condenser is dirty, it may be cleaned and de-scaled by the following procedure:
1. Turn unit off and disconnect main power.
2. Disconnect water pressure switch tubing by loosening 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:
• Oakite Aluminum Cleaner® 164, available as a powder in 20 kg (44 lb) pails and 205 kg (450 lb) drums.
• 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.
• Fresh clean water.
• Acid proof pump and containers or bottles with rubber hose.
