Carrier 38TXA User Manual

Page 2

existing R-22 TXV must be replaced with a factory-approved TXV
specifically designed for R-410A. To replace an R-22 TXV see
accessory kit instructions.

NOTE:

FK4 fan coils are equipped with an R-22 TXV. If an FK4

fan coil is used with an R-410A air conditioner, the R-22 TXV
must be replaced.

Step 4—Install AccuRater® Piston and Ring

ACCURATER PISTON

1. If unit is to be installed with a piston metering device, check

indoor piston to see if it matches required piston on outdoor
unit rating plate. If it does not match, replace with piston
shipped with outdoor unit. The piston shipped with outdoor
unit is correct for any approved indoor coil combination.

2. After correct piston is installed, locate brass piston ring

shipped in piston bag. Install piston ring behind metering
piston as shown in Fig. 2. The piston ring will ensure piston
stays seated during all operating conditions.

Step 5—Make Piping Connections

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.

Outdoor units may be connected to indoor sections using accessory
tubing package or field-supplied refrigerant grade tubing of correct
size and condition. For tubing requirements beyond 50 ft, consult
Application Guideline and Service Manual for air conditioners
with R-410A.

INSTALLATION RECOMMENDATIONS

1. Locate unit away from windows.

2. Ensure that vapor and liquid tube diameters are appropriate to

capacity of unit. (See Table 1)

3. Run refrigerant tubes as directly as possible by avoiding

unnecessary turns and bends.

4. Leave some slack between structure and unit to absorb

vibration.

5. When passing refrigerant tubes through wall, seal opening

with RTV or other pliable silicon-based caulk. (See Fig. 3.)

6. Avoid direct lineset contact with water pipes, ductwork, floor

joists, wall studs, floors, and walls.

7. Do not suspend refrigerant tubing from joists and studs with a

rigid wire or strap which comes in direct contact with tubing.
(See Fig. 3.)

8. Ensure that tubing insulation is pliable and completely sur-

rounds vapor line.

9. When necessary, use hanger straps which are 1 in. wide and

conform to shape of tubing insulation. (See Fig. 3.)

10. Isolate hanger straps from insulation by using metal sleeves

bent to conform to shape of insulation.

DO NOT BURY MORE THAN 36 IN. OF REFRIGERANT
TUBING IN GROUND. If any section of tubing is buried,
there must be a 6-in. vertical rise to the valve connections on
the outdoor unit. If more than the recommended length is
buried, refrigerant may migrate to cooler buried section
during extended periods of unit shutdown, causing refrigerant
slugging and possible compressor damage at start-up.

Fig. 2—Accurater Components

A95615

PISTON

BODY

FLARE
ADAPTOR

PISTON

RING

PISTON

RETAINER

STRAINER

FIELD

CONNECTION

LIQUID LINE STRAINER

APPROX. 2” LONG

STRAINER LABEL
(AFFIX TO LIQ. LINE
NEAR STRAINER LOCATION)

Fig. 3—Piping Installation

A94028

INSULATION

VAPOR TUBE

LIQUID TUBE

OUTDOOR WALL

INDOOR WALL

LIQUID TUBE

VAPOR TUBE

INSULATION

CAULK

Avoid contact between tubing and structure

NOTE:

THROUGH THE WALL

HANGER STRAP

(AROUND VAPOR

TUBE ONLY)

JOIST

″

MIN.

SUSPENSION