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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

Summary of content (12 pages)

PAGE 1
Carrier International Corporation 38GP Installation, Operation, and Maintenance Instructions (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.
PAGE 2
AIR IN NOTE: Fan position on motor shaft should be as close to motor as possible without touching.
PAGE 3
All of the above steps are covered in general by the likenumbered sections of the Standard Installation Practices in the back of this manual; therefore, this Installation Instruc tion will contain only supplementary information applicable to installing the condensing unit. It should be noted that evacuation and purging are not normally required when a complete matching system is installed.
PAGE 4
tively removes itself electrically from circuit. When contac tor 2D or 2M is deenergized, start thermistor 4K will auto matically reset itself in approximately 3 to 5 minutes. TABLE Vili—RECOMMENDED SUCTION-TUBE DIAMETERS Size 025 040 047 054 Suction-Tube Length (Feet) 0 to 120 120 to 150 Oto 60 60 to 135 Oto 85 85 to 150 0 to 65 65 to 150 Recommended Diameter (inches) 5/8 7/8 3/4 7/8 7/8 1-1/8 1-1/8 1-3/8 Start Kit 2K and 4D NOTE: The above table is based on a tube loss of 2°F.
PAGE 5
TERMINAL BLOCK Figure 3—Typical Single-Phase Wiring Figure 4—Typical Three-Phase Wiring -------- FIELD LOW VOLTAGE ooo --------- FIELD HIGH VOLTAGE ---------- FACTORY LINE VOLTAGE XXX ---------- FACTORY LOW VOLTAGE STARTING CIRCUIT LINE VOLTAGE (WHEN USED) ALTERNATE STARTING CIRCUIT LINE VOLTAGE (WHEN USED) LEGEND 2A-Contactor SPST 2D-Contactor DPST 2K-Start Relay (When Used) 2M-Contactor TPST (N.O.
PAGE 6
Check fan motor and blade for cleanliness and lubrica Be careful not to damage the coil fins. Be sure to wash the tion each cooling season. Clean and lubricate as dirt from the coil. Space has been provided under the coil to necessary. flush away the dirt. Drain holes are also provided in the 3. Check electrical connections for tightness and controlsbase pan. Be sure they are open. If the coil is coated with oil for proper operation each cooling season.
PAGE 7
6. To reassemble unit: a. Reinstall top cover with fan motor and blade. b. Push excess motor leads back into wire retainer and replace all screws. c. Reconnect electrical power and check fan for proper operation. reassemble properly, (Use new connector if old one is burned or corroded.) and secure tightly. Electrical controls are diffi cult to check without proper instrumentation; therefore, reconnect the electrical power to the unit and observe the unit through one complete operating cycle.
PAGE 8
tionable, consideration should be given to a shielding barrier. Consult your Distributor or the current pubhcation of ARI Standard 270 for assistance in determin ing a suitable location with minimum of operating sounds. 8. Keep distance between evaporator coil and condensing unit as short as possible. 9. Consult your Distributor regarchng roof-mounted con densing units on multilevel buildings. OPENING AND CLOSING OF VALVES 1. Use correct tool. 2. Remove valve stem cap. 3.
PAGE 9
1. Connect evacuation equipment to system through gauge manifold. 2. Evacuate system, following appropriate steps for type of evacuation equipment used. 3. Pressurize system with refrigerant to 10 psig and open (Turn counterclockwise.) both service valves. 4. Remove gauge manifold. Replace valve stem and gauge port caps on both service valves (Be sure they are tight.) if system is to be left in evacuated condition. It wfll not be necessary to remove gauge manifold if checking-charge procedure is to follow.
PAGE 10
UNTIL ALL REFRIGERANT CONNECTIONS HAVE BEEN MADE AND BOTH SERVICE VALVES HAVE BEEN CHECKED FOR THE OPEN POSITION. (TURNED COUNTERCLOCKWISE.) IT IS NECESSARY TO REMOVE THE VALVE STEM CAPS TO CHECK. The single-phase compressor motor used in this condensing unit may be a permanent-spht-capacitor-tj^e (PSC) motor, designed to start under low-load conditions only; therefore, make sure that the system pressures have equahzed before attempting to start the unit: this takes approximately 3 minutes.
PAGE 11
certain at this time ail components are operating in correct sequence. 12. Thoroughly explain to owner(s): a. Operation of air conditioning system (thermostat, reset controls, etc.). b. Care and maintenance instructions (cleaning air fil ters, condenser and evaporator coils, blower wheel. —11 — and lubrication of all motors and blower bearings). c. Factory and dealer warranties and how to obtain service, if necessary. d.
PAGE 12
Carrier International Corporation ■ number one air conditioninq maker Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligation. 38GP-C12SI-CIC Supersedes 38GP-C10SI-CIC Printed in U.S.A.