6.10.2 Checking High Pressure Switch
WARNING
Do not use a nitrogen cylinder without a pressure regulator. Do not use oxygen in or near a refrigeration system as an explosion may occur.
NOTE
The high pressure switch is
a. Remove switch as outlined in paragraph 6.10.1
b. Connect ohmmeter or continuity light across switch terminals. Ohm meter will indicate no resistance or continuity light will be illuminated if the switch closed after relieving compressor pressure.
c. Connect hose to a cylinder of dry nitrogen. (See Figure
c. Unsolder discharge line and remove the line to the receiver or
d. Remove coil mounting hardware and remove the coil.
e. Install replacement coil and solder connections.
f.
6.12 CONDENSER FAN AND MOTOR ASSEMBLY
WARNING
Do not open condenser fan grille before turning power OFF and disconnecting power plug.
The condenser fan rotates
1
2
3
4
5
6
1.Cylinder Valve and Gauge
2.Pressure Regulator
3.Nitrogen Cylinder
4.Pressure Gauge (0 to 36 kg/cm@ = 0 to 400 psig)
5.
6.1/4 inch Connection
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.
Figure 6-9 High Pressure Switch Testing
d. Set nitrogen pressure regulator at 26.4 kg/cm@ (375 psig) with
e. Close valve on cylinder and open
f.Open cylinder valve. Slowly close
g.Slowly open
6.11 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 refrigerant charge.
b. Remove the condenser coil guard.
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 is within 2.0 ± .07 mm (0.08” ¦ 0.03”) from the outside of the orifice open- ing. Spin fan by hand to check clearance.
e. Close and secure condenser fan screen guard.
f. Apply power to unit and check fan rotation. If fan motor rotates backward, reverse wire numbers 5 and 8.
6.13
On units equipped with a
a. To Check
1.Test for a restricted or plugged