Carrier 38GP - Manual

Carrier
International
Corporation
Installation, Operation,
and Maintenance Instructions
38GP
(50-HZ)
Important—Read Before Installing
Check the power supply: Voltage, frequency, and phase
must correspond to that specified on the unit rating plate.
The power supply must be able to handle the additional elec­
trical load imposed by this equipment.
The Model 38GP Condensing Unit does not have a trans­
former; therefore, the fan-coil or blower package trans­
former (or another source) must be used as a low-voltage
supply. The low-voltage supply must have an additional
capacity of 15VA to handle the load imposed by this
equipment.
The compressor motor is equipped with em internal protec­
tor. Excessive current or temperature wiU cause the protec­
tor to open, giving the indication of an open circuit in the
motor winding. Sufi&cient time should be allowed for the
overload to reset before assuming the compressor has an
open winding.
The compressor motor is designed to start under low-load
conditions only (high- and low-side pressures equalized) and
within the specified operating voltage range. Make sure
that system pressures have equahzed before attempting to
start the unit. Equahzation takes approximately 3 minutes.
The owner should be informed not to short-cycle the unit
with the thermostat as this wiU cause the compressor to
tripout on overload.
Each condensing unit is shipped with a refrigerant charge
that is adequate for most systems using matching coils and
refrigerant tubing kits. This charge is adequate for up to 25
feet of interconnecting tubing. For tube lengths greater or
less than 25 feet, the refrigerant charge must be adjusted.
See Table II for charge quantity and refer to refrigerant-
tube sizing. Tables IV through VII, for the adjustment re­
quirements.
NOTE: If additional refrigerant is needed, a crankcase heater
wül probably be required. (Refer to the appropriate refriger­
ant-tube sizing table.) When a crankcase heater is used,
inform the homeowner that power must be turned on to the
air conditioning unit at least 12 hours before the thermostat
is turned to the COOLING position for spring startup.
A filter-drier is not normally required in the system when a
complete system is used (condensing unit, refrigerant tub­
ing, and evaporator coil). For exceptions to this rule, see
Section II, “Installing Refrigerant Tubing,” of the Stand­
ard Installation Practices booklet packaged with the unit.
To obtain optimum performance and efficiency with match­
ing or mix-matched evaporator coils, it may be necessary to
change the metering device. See Table IX for necessary
changes.
Figure 1—Model 38GP
GENERAL
The condensing unit, as shipped from the factory, includes:
a compressor, a condenser fan and motor, hquid and suction
service valves, an air-cooled condenser coil, and all neces­
sary electriceil controls.
The condensing unit is designed for use with matching
evaporator coils. An expansion valve is not required. How­
ever, the unit can be used with a suitable evaporator coil
that uses an expansion valve with a pressure equalization
feature during the off cycle. Expansion valves with this fea­
ture.are available from your Distributor.
Installation comprises the following steps (sections):
I. Locating the Unit
II. InstaUing Refrigerant Tubing
III. Leak Testing
IV. Purging (if required)
V. Evacuation (if required)
VI. Electrical Connections
VII. Checking Charge
VIII. Adjusting Charge
^Carrier International Corporation 1984 38GP-C12SI-CIC