Trane 4NXCA024AC3HCA, 4NXCB025AC3HCA, 4NXCA018AC3HCA, 4NXCB032AC3HCA, 4NXCB036AC3HCA Installer's Manual
...
Installer’s Guide
WARNING
!
Cased Aluminum "Convertible" Coils
18-AD28D1-2
4NXCA018AC3HCA
4NXCA024AC3HCA
4NXCB025AC3HCA
4NXCB032AC3HCA
4NXCB036AC3HCA
4NXCD063BC3HCA
4NXCB031AC3HCA
ALL phases of this installation must comply with NATIONAL, STATE AND LOCAL CODES
IMPORTANT — This Document is customer property and is to remain with this unit. Please return to service informa-
tion pack upon completion of work.
WARNING (Medium/high pressure)
Contains Refrigerant!
System contains oil and refrigerant under high pressure. Recover refrigerant to relieve pressure before
opening the system. See unit nameplate for refrigerant
type. Do not use non-approved refrigerants, refrigerant substitutes, or refrigerant additives.
Failure to follow proper procedures or the use of
non-approved refrigerants, substitutes, or refrigerant additives could result in death, serious injury, or
equipment damage.
Table of Contents
General ............................................................................... 1
Application Information ................................................ 1
Recommendation ............................................................. 1
Furnace in Upflow Position .......................................... 2
Furnace in Downflow Position ..................................... 3
Furnace in Horizontal Left Position ........................... 4
Furnace in Horizontal Right Position ........................ 6
Maximum Airflow Setting, CFM ................................... 7
Installing Refrigerant Lines ......................................... 7
Field Fabricated Interconnecting Lines .................... 7
Brazing to Evaporator .................................................... 7
Leak Check........................................................................ 8
Condensate Drain Piping .............................................. 8
Cleaning the Coil ............................................................. 8
Outline Drawings ............................................................ 9
Replacing TXC***S3 Coil with NXC***C3 Coil ........11
TXV Change Out .............................................................11
NOTE:
The 4NXCB025AC3HCA and the 4NXCB031AC3HCA coils
are not direct replacements for previously installed 4TXC
coils. There is a height difference in the two coils models
between the two coil families.
A. GENERAL
These coils are designed for use in combination with a heat
pump or cooling outdoor section using R-410A REFRIGER-
ANT. These coils may be converted for use with a horizontal
furnace as well.
The 4NXC equipment has been evaluated in accordance with
the Code of Federal Regulations, Chapter XX, Part 3280 or the
equivalent. “Suitable for Mobile Home use” The height of the
Furnace, Coil and discharge duct work must be 7 ft. or less.
Inspect the coil for shipping damaged. Notify the transportation company immediately if the coil is damaged.
B. APPLICATION INFORMATION
1. FURNACE AND COIL
The coil MUST BE installed downstream (in the outlet air)
of the furnace. The coil apex can face into or away from the
direction of the airflow, depending on horizontal left or right
application.
Figure 1
These coils fit the 17½" and 24½" width furnaces without
any adapters in vertical upflow, downflow, or horizontal application. Some coils require model specific changes
to the coil. See application specific sections.
2. INDOOR UNIT AIRFLOW
Indoor unit must provide the required airflow for the heat
pump or cooling combinations approved for these coils.
IMPORTANT: Review your installation requirements. Check
the table on the outline drawings and note all dimensions
for your coil before beginning the installation.
A341869P25
Installer’s Guide
CAUTION
!
UPFLOW
FURNACE
CASED
COIL
SCREWS
(BOTH SIDES)
STANDOFFS
(BOTH SIDES)
STANDOFFS (4)
DRILL SCREWS (4)
Remove
and
Discard
Replace
C. RECOMMENDATION
If a coil is part of the total system installation, use the Installer’s Guide packaged with the furnaces, and outdoor sections,
and thermostat for physically installing those components.
D. FURNACE IN UPFLOW POSITION
1. UPFLOW COIL CONVERSION (Model 4NXCD063
only)
a. Remove the factory installed two-piece baffle assembly from the apex of the coil by removing the 5/16”
hex head screws. See Figure 2.
b. Replace only the top baffle using the same screws
previously removed.
c. The (2) outer water diverter baffles and the two
piece factory baffle must be removed and the top baffle
replaced for maximum efficiency.
d. Remove the coil by sliding the coil out of the coil
enclosure.
e. Remove the (2) outer water diverter baffles by
removing the 5/16” hex head screws. See Figure 3.
Coil is pressurized with 10 to 20 psi nitrogen. Remove
the valve core on the pressure tap to release the pressure before un-sweating the tubing caps. If no pressure
is released, check for leaks.
2. UPFLOW GAS FURNACE
a. Turn furnace power OFF and remove the flue pipe if
necessary.
b. Apply gasket material (duct seal field supplied) to
ALL mating surfaces between the furnace and the coil
case.
c. Set the coil case on top of the furnace. Connect the
ductwork to the coil case.
d. Replace the furnace flue pipe if it has been removed
and fasten it securely.
e. Turn the furnace power ON.
3. UPFLOW GAS FURNACE - Add-on Cooling
a. Turn furnace power OFF and remove the flue pipe if
necessary.
b. Disconnect and remove a sufficient portion of the
supply ductwork to provide clearance for the cased coil.
c. Install the cased coil following the Installation In-
struction section D-1 of these instructions.
d. Reconnect the ductwork to the coil case.
e. Replace the furnace flue pipe if it has been removed
and fasten it securely.
f. Turn the furnace power ON.
Figure 2
Figure 3
FOR VERTICAL
INSTALLATIONS:
Standoffs and screws (See Figure 4) are included with
the cased coils for attachment to the furnace. There are
clearance alignment holes near the bottom of the coil wrap-
Drill Screw
per. Drill screws are used to engage the top flanges of the
furnace. The standoff is inserted into the cabinet alignment
hole (See Figure 4). The drill screws are inserted through
the standoffs then screwed into the furnace top flange. The
Standoff
coil is always placed downstream of the furnace airflow. The
above instructions apply if the coil is on top of an upflow
furnace.
Alignment Holes
on both sides.
Figure 4
© Trane 2013 18-AD28D1-2
E. FURNACE IN DOWNFLOW POSITION
Remove
and
Discard
Replace
1. DOWNFLOW COIL CONVERSION
Installer’s Guide
For All Downflow Coils
a. Remove the horizontal drain pan from the coil and
discard.
b. Lay the coil on its back side.
c. Locate the 4" wide gasket material found in a plastic
bag in the document pack.
d. Attach the 4" gasket material to three sides of the
bottom of the drain pan as shown. Make sure to start
by matching up the edge of the gasket material to the
inner edge of the drain pan by the coil fins and working
outwards.
e. The gasket material can be cut or ripped easily so
that it can tailored to fit. The gasket material must
cover the three sides along the entire length of the coil
as shown in Figure 5.
For 4NXCD063 Coil Only
a. Remove the factory installed two-piece baffle assem-
bly from the apex of the coil by removing the 5/16” hex
head screws. See Figure 6.
b. Replace only the top baffle using the same screws
previously removed.
c. Installation of the 1/2” wide gasket behind the front
and back triangular baffles is required for downflow applications.
d. Remove the coil by sliding the coil out of the coil
enclosure.
e. Remove the front shield from the coil.
f. Remove the coil from the drain pan.
g. Remove the front triangular two piece baffle from the
coil (do not disassemble) and apply the 1/2” wide gasket
provided to the inside surface of the front baffle. The
gasket will need to be cut in three pieces; two 31.25"
pieces for the sides and one 17.5" piece for the bottom.
See Figure 7.
h. Remove the back triangular two piece baffle from the
coil (do not disassemble) and apply the 1/2” wide gasket
provided to the inside surface of the back baffle. The
gasket will need to be cut in three pieces; two 31.25"
pieces for the sides and one 17.5" piece for the bottom.
See Figure 7.
Start
here
Figure 5
Attach Downflow
Bottom Gasket
Figure 6
Do not overlap
gasket material at
corners.
1/2" Gasket
Attach to
inside surface
of Triangular
Baffle
Figure 7
Attach Gasket to Inside Surfaces
18-AD28D1-2 3
Installer’s Guide
▲
CAUTION
!
CAUTION
!
Coil is pressurized with 10 to 20 psi nitrogen. Remove
the valve core on the pressure tap to release the pressure before un-sweating the tubing caps. If no pressure
is released, check for leaks.
2. DOWNFLOW GAS FURNACE
When a coil is used with a downflow furnace, a subbase
is not required between the coil case and combustible
flooring.
a. Place the coil case on the furnace supply air ple-
num.
b. Secure the coil case to the plenum.
c. Set the furnace on top of the coil case, making sure
that the back side of the discharge opening is snug up
against the duct flange at the top rear of the coil case.
d. Secure the coil case to the furnace.
3. DOWNFLOW GAS FURNACE -- Add On Cooling
a. Turn the furnace power OFF, remove the flue pipe,
and disconnect the fuel and power lines.
b. Raise the furnace to provide sufficient clearance to
mount the coil case beneath it. Modifications will be
required to the existing return air ductwork to permit
the furnace to be raised.
c. Place the coil case on the furnace supply air plenum.
d. Secure the coil case to the plenum.
e. Set the furnace on top of the coil case, making sure
that the back side of the discharge opening is snug up
against the duct flange at the top rear of the coil case.
f. Reconnect the flue pipe and the fuel and power lines.
g. Turn the furnace power ON.
F. FURNACE IN HORIZONTAL LEFT POSITION
Both the coil and furnace must be fully supported. Do not
attempt to suspend the coil using the brackets.
1. HORIZONTAL LEFT COIL CONVERSION (4NXCD063
Coil Only).
a. For the horizontal left configurations, the (2) outer
water diverter baffles must be removed for maximum
efficiency.
b. Remove the coil by sliding the coil out of the coil
enclosure.
c. Remove the (2) outer water diverter baffles by remov-
ing the 5/16” hex head screws. See Figure 8.
Figure 8
2. HORIZONTAL LEFT (4NXCB025 and 4NXCB031 only)
For horizontal left applications in the 4NXCB025 and the
4NXCB031 coils, the installer must remove the horizontal
drain pan retainer clips prior to installing the splash guard.
a. Remove the two screws holding the two horizontal
drain pan clips. See Figure 9.
b. Discard screws and clips.
Figure 9
4 18-AD28D1-2
Co
m
fort
TM
c
oil
CASED COIL SHOWN INSTALLED HORIZONTAL LEFT WITH A DOWNFLOW
FURNACE AND HORIZONTAL ALIGNMENT BRACKETS
BRACKETS SHIP WITH
DOWNFLOW FURNACES.
REQUIRED FOR ALIGNMENT
ON HORIZONTAL INSTALLATIONS.
AIRFLOW
FURNACE
DUCT
SPLASH
GUARD
CASED COIL
CAUTION
!
3. HORIZONTAL LEFT (All coils)
The non-condensing furnaces may be laid on either side
for horizontal application. The condensing downflow/horizontal and upflow/horizontal furnaces may only be rotated
onto their left side. Connection brackets for coil/furnace
alignment are included with the furnaces.
a. In horizontal left, the 4NXC coil case is rotated so
the apex of the coil is away from the furnace and the
auxiliary drain pan is now on the lower side.
b. The two piece baffle ships installed on the coil and is
required for horizontal left applications.
c. The base of the coil enclosure is placed flush against
the downflow/horizontal furnace. Upflow/horizontal
condensing furnaces have the coil match the top flange.
d. There are three brackets included with the downflow
furnace which are used to connect the furnace and coil
together. See Figure 10.
e. Two brackets are used to attach the rear of the coil
and furnace and one bracket is used to attach the front.
The rear brackets will use existing screws on the coil
enclosure (two on each side at the bottom). Each of the
rear brackets will be attached with the wide side of the
bracket resting on the top and bottom of the horizontal
coil and furnace (see Figure 11). Four additional screws
will be used to attach each rear bracket.
f. The front bracket is positioned as close to the cen-
ter as possible with the narrow edge against the coil
enclosure and the wide edge against the furnace . Two
screws each are driven into the coil enclosure and furnace.
g. There is a splash guard packaged with the coil. This
guard is for horizontal left coil installation only. The
guard has a bend which is inserted into the front channel of the horizontal drain pan on the outlet air side
of the coil case. The guard is then rotated downward
until it rests in the drain pan. One sheet metal screw
is driven through the coil case duct flange on the front
side and into the splash guard side hole. See Figure 12.
Installer’s Guide
CASED COIL CONNECTION
BRACKET FOR DOWNFLOW
FURNACE IN HORIZONTAL
Figure 10
Figure 11
Coil is pressurized with 10 to 20 psi nitrogen. Remove
the valve core on the pressure tap to release the pressure before un-sweating the tubing caps. If no pressure
is released, check for leaks.
Standoffs and screws (See Figure 13) are included with
the cased coils for attachment to the furnace. There are
clearance alignment holes near the bottom of the coil wrapper. Drill screws are used to engage the top flanges of the
furnace. The standoff is inserted into the cabinet alignment
hole (See Figure 13). The drill screws are inserted through
the standoffs then screwed into the furnace top flange. The
coil is always placed downstream of the furnace airflow. The
coil and furnace must be fully supported when used in the
horizontal position. The standoffs and screws are strictly
for securing alignment, not for support in horizontal.
18-AD28D1-2 5
Figure 12
Drill Screw
Standoff
Alignment Holes
on both sides.
Figure 13
Installer’s Guide
▲
CAUTION
!
UPFLOW MODEL IN
HORIZONTAL RIGHT AIRFLOW POSITION
Airflow
Co
m
fort
TM
c
oil
CASED COIL
Co
m
fort
TM
c
oil
CASED
COIL
UPFLOW
FURNACE
TOP COIL FLANGE
FITS INSIDE OF
FURNACE
TOP FLANGE FOR
HORIZONTAL RIGHT
APPLICATION
UPFLOW
Remove
and
Discard
Replace
CAUTION
!
G. FURNACE IN HORIZONTAL RIGHT POSITION
Both the coil and furnace must be fully supported. Do not
attempt to suspend the coil using the brackets.
1. HORIZONTAL RIGHT COIL CONVERSION (For
4NXCD063 Coil Only).
a. For the horizontal right configurations the two-piece
factory baffle must be removed and the top baffle replaced for maximum efficiency.
b. Remove the factory installed two-piece baffle assembly from the apex of the coil by removing the 5/16” hex
head screws. See Figure 14.
c. Replace only the top baffle using the same screws
previously removed.
d. The (2) outer water diverter baffles must be removed
for maximum efficiency.
e. Remove the coil by sliding the coil out of the coil
enclosure.
f. Remove the (2) outer water diverter baffles by remov-
ing the 5/16” hex head screws. See Figure 15.
IMPORTANT:
The 4NXC cased coil must be placed downstream of the
furnace, with the apex of the coil always pointing opposite
the direction of the airflow for horizontal right installation.
This placement supersedes previous furnace Installer's
Guide stating install "with the apex of the coil pointing in
the direction of airflow for horizontal application." See
Figure 16.
Figure 14
Figure 15
2. When the noncondensing Upflow/Horizontal furnace is
placed on its right side for right airflow, the furnace top
flange meets the cased coil top flange. The coil flange fits
inside of the furnace flange. See Figure 17.
3. There are three holes in the furnace top flange which
can be used for pilot holes to connect and align the furnace
and coil. There are self drilling screws included which
can be used for this connection. Seal all gaps between the
furnace and coil.
Figure 16
Coil is pressurized with 10 to 20 psi nitrogen. Remove
the valve core on the pressure tap to release the pressure before un-sweating the tubing caps. If no pressure
is released, check for leaks.
6 18-AD28D1-2
Figure 17
Installer’s Guide
▲
CAUTION
!
H. MAXIMUM AIRFLOW SETTING, CFM
NOTE:
Water blow-off could occur in certain installation positions if the airflow setting exceeds the maximum values
listed.
Maximum airflow setting, CFM
Coil
4NXCA018AC3HCA
4NXCA024AC3HCA
4NXCB025AC3HCA
4NXCB031AC3HCA
4NXCB032AC3HCA
4NXCB036AC3HCA
4NXCD063BC3HCA 2250 2250 1750
I. INSTALLING REFRIGERANT LINES
1. The following steps are to be considered when installing
the refrigerant lines:
a. Determine the most practical way to run the lines.
b. Consider types of bends to be made and space limitations.
NOTE:
Large diameter tubing sizes will be difficult to bend once
it has been shaped.
c. Determine the best starting point for routing the refrigerant
tubing --INSIDE OR OUTSIDE THE STRUCTURE.
d. Provide a pull through hole of sufficient size to allow both
liquid and gas lines to clear. The location of this hole (if practical) should be just above the wall plate which is resting on
the foundation.
e. Be sure the roll of tubing is of sufficient length.
f. Uncoil the tubing - do not kink or dent.
g. Route the tubing making all required bends and properly
secure the tubing before making final connections.
NOTE: These lines must be isolated from the structure and
the holes must be sealed weather tight after installation.
Horizontal
Left
900 900 800
1125 1125 1000
1200 1350 1200
Horizontal
Right
Downflow
K. BRAZING TO EVAPORATOR SECTION
IMPORTANT:
Do not unseal refrigerant tubing until ready to cut and fit
refrigerant lines.
There is only a holding charge of dry air in the indoor coil,
therefore no loss of operating refrigerant charge occurs when
the sealing plugs are removed.
NOTE:
TXV bulb MUST be protected (wrapped with wet rag) or
removed, while brazing the tubing. Overheating of the
sensing bulb will affect the functional characteristics and
performance of the comfort coil.
1. Remove both seals from the indoor coil. The braze caps
are soft soldered.
2. Field supplied tubing should be cut square, round and free
of burrs at the connecting end. Clean the tubing to prevent
contaminants from entering the system.
3. Run the refrigerant tubing into the stub tube sockets
of the indoor unit coil.
PAINTED AREAS OF THE UNIT MUST BE SHIELDED
DURING BRAZING.
4. Braze and evacuate according to indoor and outdoor installation instructions.
5. Flow a small amount of nitrogen through the tubing while
brazing.
6. Use good brazing technique to make leakproof joints.
7. Minimize the use of sharp 90 degree bends.
8. Insulate the suction line and its fittings.
9. Do NOT allow un-insulated lines to come into contact with
each other.
Do NOT open refrigerant valve at the outdoor unit until the
refrigerant lines and coil have been brazed, evacuated, and
leak checked. This would cause contamination of the refrigerant or possible discharge of refrigerant to the atmosphere.
J. FIELD FABRICATED INTERCONNECTING LINES
1. The following procedure should be used for connecting
tubing to the coil or the Outdoor Unit.
2. More information concerning the installation of refrigerant lines is covered in the Installers Guide packaged with the
outdoor unit. Evacuation, leak testing and brazing procedures
are included in those instructions before starting the installation of refrigerant lines.
18-AD28D1-2 7
Installer’s Guide
2" MIN.
2" MIN.
CAP OR PLUG
Trap must be within 4'
of furnace / air handler
condensate drain connection.
Close as possible
L. LEAK CHECK
1. Using a manifold gauge, connect an external supply of dry
nitrogen to the gauge port on the liquid line.
2. Pressurize the connecting lines and indoor coil to 150 PSIG
maximum.
3. Leak check brazed line connections using soap bubbles.
Repair leaks (if any) after relieving pressure.
4. Evacuate and charge the system per the instructions pack-
aged with the outdoor unit.
M. CONDENSATE DRAIN PIPING
Condensate drain connections are located in the drain pan
at the bottom of the coil/enclosure assembly. The female
threaded fitting protrudes outside of the enclosure for external
connection. A field fabricated trap is required in this line.
See Figure 18.
1. The drain hole in the drain pan must be cleared of all
insulation.
2. Insulate the drain line to prevent sweating and dripping.
It is always recommended that an auxiliary drain pan be installed under a horizontally installed evaporator coil or 90%
gas furnace. Connect the auxiliary drain line to a separate
drain line (no trap is needed in this line).
N. CLEANING THE COIL
The two piece door (3-piece on 24.5" wide models) allows
removal of the outer casing doors without interference from
refrigerant or condensate lines. Once the outer doors are
removed the split inner coil panels can be easily removed.
The inside and outside of the coil can be easily cleaned with
a brush and vacuum with the panels removed. See Figure 19.
The foil covered insulation on 4NXC coils should be wiped
down and residual dirt and dust should be vacuumed up to
maintain good air quality. See Figure 20.
Field fabricated trap
Figure 19
Figure 18
Figure 20
8 18-AD28D1-2
7/8
Installer’s Guide
From Dwg. D344665
19-3/8
2-1/2
15/16
(All dimensions are in inches)
PRIMARY DRAIN
3/4” NPT
FOR VERTICAL POSITION
PLUGGED
SECONDARY DRAIN
3/4” NPT
FOR VERTICAL POSITION
21-1/2
18-1/8 OPENING
IN WRAPPER
4NXCB032AC3HCA
4NXCB036AC3HCA
4NXCB025AC3HCA
4NXCB031AC3HCA
4NXCA018AC3HCA
4NXCA024AC3HCA
MODEL
14-1/2 17-1/2
WEIGHT (LBS.) 32 36 38
REFRIGERANT CONTROL TXV (NON-BLEED)
HEIGHT "A" (IN.) 17-1/2 18-1/4 22-1/2
OVERALL WIDTH "B" (IN.) 14-1/2 17-1/2 17-1/2
OPENING WIDTH "C" (IN.) 13-5/8 16-5/8 16-5/8
TOP OPENING "D" 12-3/4 15-3/4 15-3/4
GAS CONNECTION 3/4 BRAZE
LIQUID CONNECTION 3/8 BRAZE
MATCHED FURNACE WIDTH
(NO ADAPTER REQUIRED)
B
4NXCB032AC3HCA, and 4NXCB036AC3HCA
Outline Drawing for 4NXCA018AC3HCA, 4NXCA024AC3HCA, 4NXCB025AC3HCA, 4NXCB031AC3HCA,
D
1/4
2-3/4
5-3/8
1-9/16
1-3/4
3-11/16
10-1/4
A
1-1/4
C
1-3/4
3-5/8
DRAIN PAN PLASTIC
Dimension may vary slightly by coil model
18-AD28D1-2 9
Installer’s Guide
22-3/4
7/8
From Dwg. D344723
19-3/8
(All dimensions are in inches)
3-1/8
PRIMARY DRAIN
PLUGGED
3/4” NPT
FOR VERTICAL POSITION
SECONDARY DRAIN
3/4” NPT
FOR VERTICAL POSITION
21-1/2
18-1/8 OPENING
IN WRAPPER
MODEL 4NXCD063BC3HCA
WEIGHT (LBS.) 80
REFRIGERANT CONTROL TXV (NON-BLEED)
HEIGHT (IN.) 30-1/4
OVERALL WIDTH (IN.) 24-1/2
OPENING WIDTH (IN.) 23-5/8
TOP OPENING 22-3/4
24-1/2
GAS CONNECTION 7/8 BRAZE
LIQUID CONNECTION 3/8 BRAZE
MATCHED FURNACE WIDTH
(NO ADAPTER REQUIRED)
DRAIN PAN PLASTIC
Outline Drawing for 4NXCD063BC3HCA
24-1/2
23-5/8
1-3/4
3-1/2
1/8
2-3/4
10 18-AD28D1-2
30
5-3/8
15-5/8
1-3/4
3-3/4
1-9/16
Installer’s Guide
O. REPLACING A TXC***S3 COIL WITH A
4NXC****C3 COIL (4NXCB032, 4NXCB036, and
4NXCB063 Coil Only)
1. Determine which refrigerant is being used by the
system. This coil is shipped ready for R-410A. The
TXV is correct for R-410A systems only.
2. Recover refrigerant in the system.
3. Disconnect refrigerant lines.
4. Disconnect drain lines.
5. Slide the old coil out.
6. Discard the coupling panel and front access panel from
the existing AS3 cabinet.
7. Slide the new coil in the place of the old coil.
8. Install the manifold panel from the new 4NXC coil
cabinet to the existing coil cabinet.
IMPORTANT:
When unbrazing and brazing lines, make sure to wrap a
wet rag around the liquid or suction line before the TXV
body to protect the TXV from over heating during brazing.
NOTE:
TXV bulb MUST be protected (wrapped with wet rag) or
removed, while brazing the tubing. Overheating of the
sensing bulb will affect the functional characteristics and
performance of the comfort coil.
9. Wrap a wet rag around the suction line before the TXV
sensing bulb to protect the bulb from over heating
during brazing.
10. Wrap a wet rag around the liquid line before the TXV
body to protect the TXV from over heating during
brazing.
11. Connect the field refrigerant lines. Brazing instructions
are on page 7.
12. Leak test all refrigerant piping with dry nitrogen.
13. Remove the wet rags.
14. Install the front panel from the new 4NXC coil cabinet
to the existing coil cabinet.
15. Replace the condensate drain piping per the coil
installation instructions on page 8.
16. Pull a vacuum on the refrigerant system.
17. Charge the system per the charging instructions with
the outdoor unit
P. TXV CHANGE OUT
1. Unbraze the liquid line field connection.
2. Remove the front panel and manifold panel.
3. Slide the coil out of the cabinet.
3. Snip the wire tie on the TXV and discard. Disconnect
the TXV sensing bulb and equalizer line.
4. Remove old TXV. Make sure to use a backup wrench
when loosening TXV. See Figure 21.
5. Attach the new TXV to the coil distributor assembly.
Make sure to use backup wrench as shown in Figure
21. Align the liquid line tube with the hole in the
manifold panel. Use a field supplied wire tie to attach
the TXV to the TXV mount bracket.
6. Connect the Equalizer line to the brass fitting on the
suction manifold.
7. Attach the TXV sensing bulb to the suction manifold.
The bulb should be between the 8 - 4 o’clock position on
the line.
8. Insulate the TXV sensing bulb.
9. Replace the manifold and front panels.
IMPORTANT:
When unbrazing and brazing lines, make sure to wrap a
wet rag around the liquid or suction line before the TXV
body to protect the TXV from over heating during brazing.
NOTE:
TXV bulb MUST be protected (wrapped with wet rag) or
removed, while brazing the tubing. Overheating of the
sensing bulb will affect the functional characteristics and
performance of the comfort coil.
10. Wrap a wet rag around the liquid line before the TXV
body to protect the TXV from over heating during
brazing.
11. Braze the field Liquid line to the coil.
12. Pressure test the refrigerant system using dry
nitrogen. Test all connections for leaks to ensure
integrity of the refrigerant piping system.
NOTE:
Torque specification for TXV equals 1/6 turn past finger
tight. Make sure to use a backup wrench when tightening
or loosening TXV. See Figure 21.
Figure 21
18-AD28D1-2 11
Before starting, insure the
blower wheel, indoor and outdoor
coils are clean.
Is sub cooling at the
outdoor unit between
8 to 12F?
Verify line set is
sized properly
for application
NO
YES
NO
Is superheat
< 5F?
NO
Is superheat
< 20F?
NO
Is the liquid line
temperature at indoor
coil within 8F of outdoor
liquid line temperature?
YES
Is indoor
temperature more
than 85F?
YES
The system is running at max
capacity and this may be
causing the High superheat.
Wait until indoor temperature
is less than 80F and check
superheat again.
NO
YES
Is air flow at least
350 CFM per ton?
YES
Remove sensing bulb from the
suction line. Measure superheat
at indoor coil while holding the
bulb in bare hand for one minute.
Does superheat decrease?
NO
YES
NO
Correct air
flow
problem
Measure superheat at indoor coil
YES
while placing the bulb in an ice
and water bath for one minute.
Does superheat increase?
NO
Replace the
TXV
TXV is OK
YES
Is sub cooling less
than 8F?
NO
Confirm that
charge is
correct.
Trane Inc.
6200 Troup Highway
Tyler, TX 75707
For more information contact
your local dealer (distributor)
YES
Confirm that charge
is correct and look
for dirty or restricted
outdoor coil.
Since the manufacturer has a policy of continuous product and product data improvement, it reserves the
right to change design and specifications without notice.
06/13
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