035-18200-000-B-1102
Unitary Products Group
11
DUCT CONNECTIONS
All ducts should be designed and installed in accor-
dance with all national and/or local codes.
Ducts should be sized no smaller than the duct flanges
on the unit or the electric heater (if used). Refer to the
unit dimensions (Fig. 18 and 19) and heater detail (Fig.
5) for these sizes. Refer to Form 550.13-N10.1U for
installation instructions on the electric heater.
Use flexible fiber glass or plastic cloth collars or other
nonflammable material at the unit duct connections to
minimize the transmission of noise and vibration.
Insulate all ductwork running through the uncondi-
tioned areas to prevent moisture condensation and to
provide more economical operation.
The return air duct flange is factory-mounted on the
front of the unit.
A supply air plenum (Fig. 6 and 7), a base (Fig. 8 and
9) and a return air grille (Fig. 7) are available as field-
installed accessories, and one of the following respec-
tive instructions will be packed with each.
Part No. 035-16630-000 - Supply Air Plenum
Part No. 035-16621-000 - Return Air Grille
Part No. 035-16632 - Base
The supply air plenum and the return air grille should
be used in lieu of ductwork only wen a free blow/free
return application is practical.
REFRIGERANT MAINS
Many service problems can be avoided by taking ade-
quate precautions to provide and internally clean and
dry system and by using procedures and materials that
conform with established standards.
Use hard drawn copper tubing where no appreciable
amount of bending around pipes or other obstructions
is necessary. Use long radius ells wherever possible
with one exception - small radius ells for any traps in a
vapor riser.
If soft copper is used, care should be
taken to avoid sharp bends which may cause a restric-
tion.
Fiber glass insulation and a sealing material such as
permagum should be packed around refrigerant lines
where they penetrate a wall to reduce vibration and to
retain some flexibiltiy.
Support all refrigerant lines at minimum intervals with
suitable hangers, brackets or clamps.
Braze all copper to copper joints with Sil-Fos 5 or
equivalent brazing material.
DO NOT USE SOFT
SOLDER.
Never braze or solder the liquid and vapor lines
together for support purposes, they must be completely
insulated, one from the other.
Refer to the installation instructions (035-16192-000)
for the matching outdoor unit for piping limitations, line
sizes and other design considerations.
INSTALLING REFRIGERANT MAINS
The units are evacuated and dehydrated at the factory
and shipped with a holding charge of Refrigerant-22.
The vapor and liquid connections are sealed with cop-
per discs.
If the unit has already lost its holding charge, it should
be leak tested and the necessary repairs should be
made, if the unit has maintained its holding charge, you
can assume that it has no leaks and proceed with the
installation.
The temperature required to make or break a brazed
joint is sufficiently high to cause oxidation of the copper
unless an inert atmosphere is provided.
Make sure the refrigerant in the lines has been recov-
ered then drill a small hole through the discs to prevent
any internal pressure from blowing them off and to
allow the flow of dry nitrogen through the connections
when unbrazing the closures.
The liquid and vapor connections must be piped out-
side the unit. Refer to the unit drawings for the loca-
tions and the dimensions of these connections.
Before brazing the refrigerant lines to these connec-
tions, remove the short panel from the unit frame and
slide the grommets onto the refrigerant lines. After the
brazed joints have cooled, slide the grommets back
into place and secure the panel to the unit frame.
FIGURE 12: SUPPLY AIR PLENUM FHP240
1
1.
Shipped knocked down for field assembly.