FCM/A5, FEV, FJM, FEM4, FHMA5, FMA4/5, FM(C,U)5, FS(A,M,U)4, FTMA5, F(V,X)M4, F5M4, REM4, WA(H,M,P,X) WB(G,H)L, WC(G,H)L: Service and Maintenance
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
29
3. The threads are coated with Loctite Heavy Duty Anti-Seize. It is
recommended to reapply with the same thread sealer.
4. Reconnect refrigerant tube to piston body.
5. Pressurize tubing and coil, then leak check.
6. Evacuate tubing and coil as necessary.
Liquid Tube Strainer
In R-22 all units, the TXV and refrigerant flow-control device is
protected on the indoor coil by a wire mesh strainer. It is located inside
the 3/8" liquid tube at field braze joint just outside unit casing. Access to
strainer is through field braze joint.
Aluminum Coil Repair
Repairing leaks on aluminum coils is possible using the aluminum
brazing method. Specific braze and flux material designed for aluminum
are necessary for aluminum brazing. A kit containing all materials
necessary for making and aluminum braze repair is available through
Replacement Components (kit No. 337748-751).
Do not use a previously-used wire brush to clean copper when preparing
an aluminum braze site. Copper particles in contact with an aluminum
coil may cause premature failure. Service aluminum coils are also
available as a coil repair option.
NOTE: Replacement of an indoor slope or A-coil must include recovery
and recycling of refrigerant currently in the system. Provided the
refrigerant has not been contaminated with moisture, acid, solid
particulate, or non-condensibles, it may be recovered by following the
procedures listed below. However, if the refrigerant is contaminated,
recycling or reclaiming methods are required. If leaks are present in the
system, meaning the refrigerant may be contaminated, recycling or
reclaiming methods MUST be used. Installation of new filter drier(s) is
required. The filter drier-type will depend upon the contaminants in the
system. See Split-System Residential Air Conditioners and Heat Pumps
Service Manuals for further information.
Pre-Installation
Except for coils only used with TXV fan coils, all-aluminum
replacement coils are shipped with a piston body distributor, piston, and
90 degree inlet tube with piston retainer (including Teflon seal). Coil
sizes used only with TXV fan coils include the TXV as part of the
replacement coil.
Before installation of replacement coil, verify the piston is the correct
orifice size. The correct size should be on the outdoor unit rating plate. If
in doubt, reuse the piston from the old indoor coil.
Use two wrenches to separate the 13/16" Chatleff nut from the
distributor body. The threads will contain Loctite anti-seize, do not
remove this from the threads.
Install the piston and reattach nut to finger tight plus 1/2 turn.
The distributor used on the all-aluminum replacement coil is also made
of aluminum. The distributor threads are coated with Loctite Heavy
Duty Anti-Seize which is a graphite/calcium fluoride formulation, for
applications that are free from copper, lead and sulfur. This product is
typically used in applications with an operating range of -20° F to
+2400° F (Fig. 27). When replacing a TXV it is recommended to reapply
with the same thread sealer. Extra care should be taken during brazing of
copper equalizer on the aluminum coils to prevent the braze material
from splattering on the aluminum. Also, route the copper equalizer so
that it doesn’t touch the aluminum components.
A14398
Fig. 27 – TXV Thread (Sealer) Location
Old Copper or Tin-Plated Coils with TXV
The all-aluminum replacement coil with piston will also be used for
TXV style coils by reusing the original TXV. An adapter is provided to
connect the replacement coil distributor to the original TXV (Fig. 28).
Insulation is also provided to wrap the copper adapter tube and brass
nuts to prevent any copper or brass particles from coming in contact with
the aluminum coil. Even if the adapter tube is not in contact with the
aluminum coil dripping condensation from the adapter tube can be a
mechanism of particulate transport.
A14397
Fig. 28 – Replacement Coil Distributor Adapter
If it is preferred to install the old TXV external to the cabinet due to
access, follow the steps below:
1. Field fabricate a piece of 3/8" OD copper tubing with flare and nut
to attach to the TXV outlet.
2. The piston in the replacement coil must be removed. Use two
wrenches to separate the 13/16" Chatleff nut from the distributor
body. The threads will contain Loctite anti-seize, do not remove this
from the threads.
3. Remove the piston
4. Reattach the inlet tube and tighten the nut finger tight plus 1/2 turn.
5. Remove the old coil and install replacement coil per instructions
below. Reinstall the fitting door to the cabinet.
6. Field fabricate a 3/8" OD copper tubing with flare and nut.
7. Braze this tubing and nut onto the liquid stub out.
8. Attach flare and nut to TXV outlet by tightening to finger tight plus
1/2 turn with two wrenches.
9. Drill equalizer hole into suction line and braze the equalizer into the
hole.
10. Attach the TXV bulb onto the suction line and insulate.
11. Insulate the entire TXV body and outlet tubing to prevent sweating.
Old All-Aluminum Coils with TXV
When replacing a previous all-aluminum coil that contains a TXV, the
old TXV can be reused and mounted inside the cabinet.
1. After removal of the distributor inlet tube and piston, the old TXV
is attached to the distributor with 13/16" Chatleff nut. The threads
contain Loctite anti-seize that can be reused.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution could result in equipment damage.
Use a backup wrench and do not over tighten, as deformation of the
piston body will occur, causing the piston to lodge in a partially open or
closed position.
WARNING
!
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal injury.
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.
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