Carrier 38YXA - Installation Procedures - Part 2; Piping Connections

Step 6—Check Indoor Expansion Device
For proper unit operation and reliability, units must be
installed with hard shutoff TXV specifically designed to
operate with R-410A. Do not use an R-22 TXV. Do not install
with evaporator coils having capillary tube metering devices
or pistons.
For TXV kit part number and charging instructions, refer to TXV
label in outdoor unit.
FURNACE COILS
If TXV installation is required, remove existing Accu-Rater® from
indoor coil. Refer to Fig. 5 and 6 and install TXV kit (specifically
designed for R-410A) as follows:
1. Install suction tube adapter.
2. Install liquid flare-to-sweat adapter.
3. Connect external equalizer tube to fitting on suction tube
adapter.
4. Position sensing bulb on horizontal portion of suction tube
adapter. Secure using supplied hardware.
5. Insulate bulb after installation. (See Fig. 6.)
6. Leak check all connections.
FAN COILS
If indoor unit (fan coil) comes factory equipped with a bi-flow
hard shutoff TXV specifically designed for R-410A, no TXV
change is required.
If TXV installation is required, refer to TXV kit Installation
Instructions for details on TXV installation.
Step 7—Check Defrost Thermostat
Check defrost thermostat to ensure it is properly located and
securely attached. There is a liquid header with a brass distributor
and feeder tube going into outdoor coil. At the end of 1 of the
feeder tubes, there is a 3/8-in. OD stub tube approximately 3 in.
long. (See Fig. 7.) The defrost thermostat should be located on stub
tube. Note that there is only 1 stub tube used with liquid header,
and on most units it is the bottom circuit.
Step 8—In Long-Line Applications, Install Liquid-Line
Solenoid Valve (LSV)
For refrigerant piping arrangements with equivalent lengths
greater than 50 ft or when elevation difference between indoor and
outdoor unit is greater than ± 8 ft, follow all requirements of the
Long-Line Guideline section in the Application Guideline and
Service Manual for Residential Split-System Air Conditioners and
Heat Pumps Using R-410A Refrigerant.
If required by Long-Line Application Guideline, install LSV kit
Part No. KHALS0401LLS specifically designed for R-410A Heat
Pump. LSV should be installed between filter drier and indoor coil,
as close as possible to filter drier. Follow the Installation Instruc-
tions included with accessory kit.
IMPORTANT: Flow arrow must point toward outdoor unit.
Step 9—Make Piping Connections
Relieve pressure and recover all refrigerant before system
repair or final unit disposal to avoid personal injury or death.
Use all service ports and open all flow-control devices,
including solenoid valves.
Do not leave system open to atmosphere any longer than
minimum required for installation. POE oil in compressor is
extremely susceptible to moisture absorption. Always keep
ends of tubing sealed during installation.
Fig. 4—Accessory Support Feet
A93567
Fig. 5—Typical TXV Installation
A88382
THERMOSTATIC
EXPANSION
VALVE
EQUALIZER
TUBE
SENSING
BULB
COIL
Fig. 6—Positioning of Sensing Bulb
A81032
2 O'CLOCK
10 O'CLOCK
SENSING BULB
STRAP
SUCTION TUBE
8 O'CLOCK
4 O'CLOCK
7
⁄
8
IN. OD & SMALLER
LARGER THAN
7
⁄
8
IN. OD
3