Installing a TXV
About this task:
CAUTION
Outdoor unit model numbers ending with an H have a
factory installed hard start kit, required when installing
a TXV. Outdoor unit model numbers with no H ending
may require a hard start kit. Refer to the
Technical
Guide
or
Tabular Data Sheet
for the outdoor unit.
The following are basic steps for installing a TXV kit on
XAF, XAH, or XAU coils. For detailed instructions, refer to
the
Installation Manual
provided with the TXV kit.
Important:
Refer to the
Technical Guide
or
Tabular
Data Sheet
for the outdoor section to determine the
correct TXV kit to use on this product.
1. Relieve the holding charge by depressing the
Schrader valve core on the suction manifold stub
out.
2. When the holding charge is completely discharged,
loosen and remove the Schrader valve core.
3. Place a backup wrench on the distributor, and
loosen and remove the brass distributor nut. Retain
the brass nut for use on the liquid line. Keep the
PTFE washer in place and discard the sealing disk.
4. Install the TXV onto the distributor assembly with
the supplied fittings. Ensure the PTFE washer is
seated in the distributor. Hand tighten and turn an
additional 1/4 turn to seal. See Figure 12.
Note:
Do not overtighten the fittings.
CAUTION
Do not over torque. Do not use slip joint pliers. This
will distort the aluminum distributor and the brass
fitting (potentially causing leaks).
5. Slide the nut removed in Step 3 over the supplied
liquid line. Place the supplied PTFE washer from
the TXV kit in place on the TXV and install the liquid
line to the top of the TXV. Adjust the distributor
assembly so the liquid line aligns with the hole in
the access panel. See Figure 12. Hand tighten the
liquid line and apply an additional 1/4 turn to seal.
CAUTION
The Schrader valve core
must not
be installed into
the suction line TXV equalizer line fitting. Poor system
performance or system failure could result.
Figure 12: TXV installation
6. Install the TXV equalizer line onto the vapor line by
hand tightening the 1/4-in. SAE coupling nut to the
equalizer fitting and apply an additional 1/3 turn to
CAUTION
Mount the TXV temperature sensing bulb after the
vapor line is brazed and sufficiently cooled.
7. Route the temperature sensing bulb tube for the
TXV toward the vapor line header and the TXV
equalizer tube connection port on the vapor line
header.
8. Install the TXV bulb to the vapor line near the
TXV equalizer tube connection port, using the
bulb clamps supplied with the TXV assembly.
Ensure that the bulb is making maximum contact.
See Figure 13 and Figure 14 and adhere to the
following:
a. Install the TXV bulb on the vapor line suction
header near the TXV equalizer tube connection
port. Ensure that the bulb is installed at a 10
o’clock or 2 o’clock position.
Installation Manual: XAF, XAH, and XAU Series - Full Cased and Uncased Coils for Cooling and Heat Pumps
14
Johnson Controls Ducted Systems
