Circulating Air & Filters; Ductwork - Air Flow; Bottom Return Air Opening [Upflow Models ]; Filters - Read This Section Before Installing The Return Air Ductwork - Goodman GMH95 Installation Instructions Manual

Sizing Between Single or Second Stage Regulator and Appliance*
Maximum Propane Capacities Listed are Based on 1/2" W.C. pressure drop at 11" W.C. setting.
Capacities in 1,000 BTU/hour.
Pipe or
Tubing Tubing Size, O.D. Type L
Length, 3/8" 1/2" 5/8" 3/4"
Feet
10 39 92 199 329
20 26 62 131 216
30 21 50 107 181
40 19 41 90 145
50 18 37 79 131
60 16 35 72 121
80 13 29 62 104
100 11 26 55 90
125 10 24 48 81
150 9 21 43 72
200 8 19 39 66
250 8 17 36 60
*Data in accordance with NFPA pamphlet NO. 54
Propane Gas Piping Chart II
XIII. CIR XIII. CIR CUL CULA A A A A TIN CUL
XIII. CIR XIII. CIR XIII. CIRCUL CUL
D - A F
UCTWORK IR LOW
Duct systems and register sizes must be properly designed for the
CFM and external static pressure rating of the furnace. Design the
ductwork in accordance with the recommended methods of "Air
Conditioning Contractors of America" Manual D.
Install the duct system in accordance with Standards of the Na-
tional Board of Fire Underwriters for the Installation of Air Condi-
tioning, Warm Air Heating and Ventilating Systems. Pamphlets No.
90A and 90B.
A closed return duct system must be used, with the return duct
connected to the furnace. NOTE: Ductwork must never be attached
to the back of the furnace. Flexible joints may be used for supply
and return connections to reduce noise transmission. To prevent
the blower from interfering with combustion air or draft when a
central return is used, a connecting duct must be installed be-
tween the unit and the utility room wall. Never us a room, closet, or
alcove as a return air chamber.
When the furnace is used in connection with a cooling unit, the
furnace should be installed in parallel with or on the upstream side
of the cooling unit to avoid condensation in the heating element.
With a parallel flow arrangement, the dampers or other means
used to control the flow of air must be adequate to prevent chilled
air from entering the furnace and, if manually operated, must be
equipped with means to prevent operation of either unit unless the
damper is in the full heat or cool position.
When the furnace is installed without a cooling coil, it is recom-
mended that a removable access panel be provided in the outlet
air duct. This opening shall be accessible when the furnace is
installed and shall be of such a size that the heat exchanger can be
viewed for visual light inspection or such that a sampling probe
can be inserted into the airstream. The access panel must be
made to prevent air leaks when the furnace is in operation.
When the furnace is heating, the temperature of the return air en-
tering the furnace must be between 55°F and 100°F.
B R A O
OTTOM ETURN IR PENING
The bottom return air opening on upflow models utilizes a "lance
and cut" method to remove sheet metal from the duct opening in
the base pan. To remove, simply press out the lanced sections by
hand to expose the metal strips retaining the sheet metal over the
duct opening. Using tin snips, cut the metal strips and remove the
sheet metal to free the duct flanges. Using the scribe line along
the duct flange as a guide, unfold the duct flanges around the
perimeter of the opening using a pair of seamer pliers or seamer
tongs. NOTE: Airflow area will be reduced by approximately 18% if
duct flanges are not unfolded. This could cause performance is-
sues and noise issues.
Nominal Pipe Size
Schedule 40
7/8" 1-1/8" 1/2" 3/4" 1" 1-1/4" 1-1/2"
501 935 275 567 1,071 2,205
346 630 189 393 732 1,496
277 500 152 315 590 1,212
233 427 129 267 504 1,039
198 376 114 237 448
187 340 103 217 409
155 289 89 185 346
138 255 78 162 307
122 224 69 146 275
109 202 63 132 252
100 187 54 112 209
93 172 48 100 185
TIN TIN G AIR & FIL G AIR & FIL TER TERS S S S S TER
TIN TING AIR & FIL G AIR & FIL G AIR & FILTER TER
[U M ]
PFLOW ODELS
E
DGES OF SHEET METAL HOLES MAY BE SHARP.
PRECAUTION WHEN REMOVING HOLE PLUGS.
3,307
2,299
1,858
1,559
CUT USING TIN SNIPS
913 1,417
834 1,275
724 1,066
630 976
567 866
511 787
439 665
390 590
CUT FOUR CORNERS
AFTER REMOVING SHEET
METAL
F - R
ILTERS EAD
R A D
ETURN IR UCTWORK
Filters must be used with this furnace. Discuss filter maintenance
with the building owner. Filters do not ship with this furnace, but
must be provided by the installer. Filters must comply with UL900
or CAN/ULCS111 standards. If the furnace is installed without fil-
ters, the warranty will be voided.
On upflow units, guide dimples locate the side return cutout
locations. Use a straight edge to scribe lines connecting the
dimples. Cut out the opening on these lines.
NOTE: An undersized opening will cause reduced airflow.
Refer to Minimum Filter Area tables to determine filter area require-
ments.
0453BXA
0703BXA
0704CXA
0904CXA
0905DXA
1155DXA
*Minimum filter area dictated by heating airflow requirement.
Permanent Minimum Filter Area (sq. in)
[Based on a 600 ft/min filter face velocity]
26
CAUTION
U
SE GLOVES AS A
PRESS OUT BY HAND
Duct Flange Cut Outs
T S B I
HIS ECTION EFORE NSTALLING
C O O LING AIR FLO W R EQ UIREM ENT (CFM )
600 800 1000 1200
194* 194* 240 288
--- 324* 324* 324*
--- --- 291* 291*
--- --- 432* 432*
--- --- --- 388*
--- --- --- 486*
SCRIBE LINES OUTLINING
DUCT FLANGES
T
HE
1400 1600 2000
--- --- ---
336 --- ---
336 384 ---
432* 432* ---
388* 388* 480
486* 486* 486*