Carrier 38ED - Manual (Page 10)

COMPRESSOR INTERNAL TEMPERATURE
AND/OR CURRENT SENSITIVE OVER­
LOADS reset automatically when motor internal
temperatures drop to a safe level (overload may
require up to 30 minutes to reset). When internal
overload is suspected of being open, check by using
an ohmmeter or continuity tester. If necessary, refer
to Carrier Standard Service Techniques Manual,
Chapter 2, Electrical, for complete instructions.
INHERENT FAN MOTOR PROTECTION pro­
tects motor from abnormal current and temperature.
SOLID-STATE TIME GUARD II CIRCUIT,
protects unit compressor by preventing short
cycling. Time Guard II circuit provides a 5 ± 2-
minute delay before restarting compressor after
shutdown for any reason. On normal start-up, the 5-
minute delay occurs before thermostat closes. After
thermostat closes, the Time Guard II circuit then
provides a 3-second delay to prevent contactor
chattering.
CRANKCASE HEATER — The purpose of the
heater is to keep the crankcase warm during the
off cycle and thus prevent dilution of the oil with
refrigerant. This assures good lubrication and pre­
vents loss of oil from crankcase during start-up.
CRANKCASE HEATER RELAY deactivates
heater when compressor is operating for maximum
energy efficiency.
Compatible Fitting Repair
MECHANICAL CONNECTION — Frontseat unit
service valves. Relieve refrigerant pressure from
tubing. Back off locknut from Compatible Fitting
onto tube. Cut fitting between threads and O-ring
as shown in Fig. 9. Remove tubing section remain­
ing in threaded portion of fitting. Discard locknut.
Clean, flux and insert new tube end into remaining
portion of Compatible Fitting. Wrap valve base in
wet rag. Heat and apply low-temperature (430 F)
solder.
Fig. 9 — Repair of Mechanical Connection
SWEAT CONNECTION — Frontseat unit service
valve. Relieve refrigerant pressure from tubing.
Clean and flux area around leak. Repair using low-
temperature (430 F) solder.
Evacuate or purge evaporator coil and tubing
system. Add refrigerant charge. See Refrigerant
Charging instructions described previously.
Condenser Fan Adjustment — Required fan
position is shown in Fig. 10. Adjust fan by loosening
setscrew(s) and moving fan blade up or down.
Condenser Fan Motor Removal
1. Shut off power to unit. Failure to do so may
result in electric shock or injury from rotating fan
blade.
2. Remove top cover by loosening screws and lift­
ing straight up.
3. Disconnect fan motor leads from control leads.
See Fig. 8.
4. Remove Carrier medallion by turning 4 Tinner-
man fasteners 1/4 turn each.
5. Remove screws holding fan motor/discharge
grille in place and lift assembly from unit.
6. Remove 4 nuts holding fan motor to discharge
grille. Remove motor and leads.
7. Reassembly is reverse of above procedure. Make
sure fan is positioned correctly as in Fig. 10.
Fig. 10 — Condenser Fan Position
MAINTENANCE
Lubrication
COMPRESSOR contains factory oil charge. Re­
place oil when lost. See Table 8 for oil recharge and
refer to Carrier Standard Service Techniques
Manual, Chapter 1, page 1-21, for oil recharging
procedure. Use Carrier PP33-1, Texaco WFI-32 or
Suniso 3GS oil.
FAN MOTOR BEARINGS are prelubricated for 3
years heavy duty or 5 years normal duty. When
lubrication is necessary, send motor to authorized
motor repair shop.
Coil Repair — A flare-union coupling repair kit is
available, with instructions, from Carrier Service
parts.
Coil Cleaning to be done at the beginning of
each cooling season or more often if required.
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