Service Manual

SERVICE AND MAINTENANCE FAN COILS
496 08 8001 02 27
Specifications subject to change without notice.
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.
CAUTION
!
LIQUID TUBE STRAINER
In 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−in. 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 an
aluminum coil braze repair is available through FAST (kit
number 1184905). Do not use a wire brush previously used 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.
COIL & CONDENSATE PAN REMOVAL AND
REPLACEMENT
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.
CAUTION
!
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 is free from copper,
lead and sulfur. This product is typically used in applications
with an operating range of −20°F to +2400°F. (See Figure 23)
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.
Figure 23 − TXV Thread (Sealer) Location
Loctite
Washer
A14398
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. (See Figure 24) 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.
Figure 24 − Replacement Coil Distributor Adapter
A14397
If it is preferred to install the old TXV external to the cabinet
due to access, follow the steps below:
d. Field fabricate a piece of 3/8” OD copper tubing with
flare and nut to attach to the TXV outlet.
e. 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.
f. Remove the piston
g. Reattach the inlet tube and tighten the nut finger
tight plus 1/2 turn.
h. Remove the old coil and install replacement coil per
instructions below. Reinstall the fitting door to the
cabinet.
i. Field fabricate a 3/8” OD copper tubing with flare
and nut.
j. Braze this tubing and nut onto the liquid stub out.
k. Attach flare and nut to TXV outlet by tightening to
finger tight plus 1/2 turn with two wrenches.
l. Drill equalizer hole into suction line and braze the
equalizer into the hole.