Carrier 38TUA, Installation And Start-Up Instructions Manual

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To avoid personal injury or death, do not supply power to unit
with compressor terminal box cover removed.
NOTE:
Install branch circuit of adequate size per NEC to handle
unit starting current. Locate disconnect within sight from and
readily accessible from unit per Section 440-14 of NEC.
The unit cabinet must have an uninterrupted or unbroken
ground to minimize personal injury if an electrical fault
should occur. The ground may consist of electrical wire or
metal conduit when installed in accordance with existing
electrical codes. Failure to follow this warning can result in an
electrical shock, fire, or death.
ROUTE GROUND AND POWER WIRES
Remove access panel and control box cover to gain access to unit
wiring. Extend wires from disconnect through power wiring hole
provided and into unit control box.
CONNECT GROUND AND POWER WIRES
Connect ground wire to ground connection in control box for
safety. Connect power wiring to contactor as shown in Fig. 4.
CONNECT CONTROL WIRING
Route 24-v control wires through control wiring grommet and
connect leads to control wiring. (See Fig. 5.)
Use No. 18 AWG color-coded, insulated (35° C minimum) wire.
If thermostat is located more than 100 ft (30.48m) from unit as
measured along the control voltage wires, use No. 16 AWG
color-coded wires to avoid excessive voltage drop.
All wiring must be NEC Class 1 and must be separated from
incoming power leads.
Use furnace transformer, fan-coil transformer, or accessory trans-
former for control power, 24-v/40va minimum.
NOTE:
Use of available 24-v accessories may exceed the mini-
mum 40-va power requirement. Determine total transformer lead-
ing and increase the transformer capacity or split the load with an
accessory transformer as required.
Step 8—Compressor Crankcase Heater
When equipped with a crankcase heater, furnish power to heater a
minimum of 24 hrs before starting unit. To furnish power to heater
only, set thermostat to OFF position and close electrical disconnect
to outdoor unit.
A crankcase heater is required if the refrigerant tubing is longer
than 50 ft (15.24m). Refer to Residential Split System Long-Line
Application Guideline.
Step 9—Install Electrical Accessories, If Any
Refer to the individual instruction packaged with the kit or
accessory when installing.
Step 10—Start-Up and Check Charge
To prevent compressor damage or personal injury, observe
the following:
• Do not overcharge system with refrigerant.
• Do not operate unit in a vacuum or at negative pressure.
• Do not disable low-pressure switch
In scroll compressor applications:
• Dome temperatures may be hot.
Table 2—Accessory Usage
ACCESSORY
REQUIRED FOR
LOW-AMBIENT
APPLICATIONS
(BELOW 55°F/12.8°C)
REQUIRED FOR
LONG-LINE
APPLICATIONS*
(OVER 50 FT/15.24M)
REQUIRED FOR
SEA COAST
APPLICATIONS
(WITHIN 2 MILES/3.22KM)
Crankcase Heater Yes Yes No
Evaporator Freeze Thermostat Yes No No
Winter Start Control Yes† No No
Accumulator No No No
Compressor Start Assist
Capacitor and Relay
Yes Yes No
MotorMaster® Control
or
Low-Ambient Pressure Switch
Yes No No
Wind Baffle See Low-Ambient Instructions No No
Coastal Filter No No Yes
Support Feed Recommended No Recommended
Liquid-Line Solenoid Valve
or
Hard-Shutoff TXV
No
See Long-Line
Application
Guideline
Yes
Ball-Bearing Fan Motor Yes‡ No No
* For tubing-line sets between 50 (15.24m) and 175 ft (53.34m), refer to Residential Split-System Long-Line Application Guideline.
† Only when low-pressure switch is used.
‡ Required for low-ambient controller (full-modulation feature) and MotorMaster® Control only.
Fig. 4—Line Power Connections
A94025
DISCONNECT
PER N.E.C. AND/OR
LOCAL CODES
CONTACTOR
GROUND
LUG
FIELD GROUND
WIRING
FIELD POWER
WIRING
BLUE
3 PHASE ONLY
4