NOTE:
A thermostatic expansion valve (TXV) is required on all
38BYB units. Step 4 refers to the installation of the TXV.
Step 4—Remove Indoor AccuRater® Piston and Install
TXV
For proper unit operation and reliability, units must be
installed with a field-supplied hard shut-off TXV. Do not
install with evaporator coils having capillary tube metering
devices or piston.
After removing existing AccuRater from indoor coil, install
field-supplied bi-flow hard shut-off TXV kit. (See Fig. 7 and 8.)
For TXV kit part number and charging instruction, refer to TXV
label in your unit. If the indoor unit (fan coil) comes factory
equipped with a bi-flow hard shut-off TXV, no TXV change is
required.
Install TXV kit to indoor coil 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. 8.)
6. Leak check all connections.
Fig. 7—Typical TXV Installation
A88382
THERMOSTATIC
EXPANSION
VALVE
EQUALIZER
TUBE
SENSING
BULB
COIL
Fig. 8—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