5
Connecting the Return and Supply Flexible Duct in
Manufactured or Modular Housing Application
The return and supply fittings are to be attached at the unit
to a suitable square to round duct converter. Your distributor
has a factory designed square to round converter transition.
The model #’s of these kits are as follows: Small Chassis
25” SQRPCH101, Medium Chassis 27.5” SQRPCH102,
Large and Extra Large Chassis 32.5:” and 36” SQRPCH103
(See Specification Sheets for Dimension details). The
SQRPCH101 has 14" duct collar on supply and 16" duct
collar (equivalent diameter, opening is oval) on the return.
The SQRPCH102 and SQRPCH103 have 14" duct collar on
supply and 18" duct collar (equivalent diameter, opening is
oval) on the return. The collars are to be slipped into the
openings, and the flanges bent around the converter. The
square to round converter is attached to the flanges of the
square duct openings. The flexible duct is then clamped
on to the collars. Once the duct is affixed to the unit,
seal
the collars and flanges with a proper waterproof sealant
(See Figure 3).
It is strongly encouraged to use appropriately sized ducts
based upon the CFM for your application (unit’s CFM). If
duct sizing through industry manuals or air duct calculators
require larger ducts than converter openings, run larger duct
size up to unit converter openings and reduce with a reducer
duct fitting or transition right at the unit.
NOMINAL S IZE (INCHE S )
NO MINA L A RE A (SQ . FT.)
10x20
1.4
14x20
1.9
14x25
2.4
15x20
2.1
16x20
2.2
16x25
2.8
20x20
2.8
20x25
3.5
25x25
4.3
M INIM U M FILTE R S IZE
TABLE 1
OUTER FLANGE
STARTER FLANGE
BEAD
SQUARE TO ROUND
DUCT CONVERTER PANEL
FIGURE 3
500 1000 1500 2000 2500 3000 3500
7
6
5
4
3
2
DIS
PO
SA
BL
E F
ILT
ER
PER
MAN
ENT
FIL
TER
Airflow - SCFM
N
o
m
in
a
l
F
ilt
e
r
A
re
a
S
q
u
a
re
F
e
e
t
FIGURE 4
Plenum Application
A suitable plenum or square duct must be constructed. The
duct cross-sectional area should be determined by industry
duct sizing manuals or air duct calculators.
On ductwork exposed to outside air conditions of
temperature and humidity, use an insulation with a good K
factor, and a vapor barrier. Industry practices should be
followed. Balancing dampers are recommended for each
branch duct in the supply system. Ductwork should be
properly supported from the unit.
NOTE: Proper sealing of all duct work and air handling
compartments is extremely important to overall unit
efficiency.
Filters
Filters are not provided with unit, and must be supplied and
installed in the return duct system by the installer. A field
installed filter grille is recommended for easy and convenient
access to the filters for periodic inspection and cleaning.
Filters must have adequate face area for the rated quantity
of the unit. See air delivery tables (Figure 4) for
recommended filter size.
PIPING
Condensate Drain
The condensate drain connection of the evaporator is a half
coupling of ¾” N.P.T. A trap must be provided to have Proper
condensate drainage.
2" Minimum
3" Minimum
A Positive Liquid Seal
Is Required
Flexible
Tubing-Hose
Or Pipe
Drain
Connection
Unit
FIGURE 5
Install condensate drain trap as shown. Use ¾ “ drain
connection size or larger. Do not operate without trap. Unit
must be level or slightly inclined toward drain.
WIRING
All wiring should be made in accordance with the
National Electrical Code.
The local Power Company
should be consulted to determine the availability of sufficient
power to operate the unit. The voltage, frequency, and phase
at the power supply should be checked to make sure it
corresponds to the unit’s RATED VOLTAGE
REQUIREMENT.
Install a branch circuit fused disconnect near the unit, in
accordance with the N.E.C. or local codes. Wire sizes and
overcurrent protection should be determined from the unit
nameplate ampacity and in accordance with Table 4 (page
6) or the N.E.C. Under no circumstances should wiring be
sized smaller than is recommended by either of these two
sources.
Fuses smaller than that recommended on the wiring diagrams
could result in unnecessary fuse failure or service calls.
The use of protective devices of larger size than indicated
could result in extensive damage to the equipment. The
manufacturer bears no responsibility for damage caused to
equipment as result of the use of larger than is recommended
size protective devices.
