8
e. If the roof jack crown is covered or blocked with
snow, the furnace will not operate properly. If
the home is located in regions where snow
accumulation exceeds 7” (HUD snowload
zones) use an external roof jack extension
p/n 901937.
f. M1 furnaces may be used with roof jacks
as tall as 170” (except M1M 056 & M1B 066
models, which are limited to 120”). An internal
roof jack extension (p/n 901935 - 10”, p/n
903107 - 18”) can be used to increase roof
jack height. All connections inside the home
must be made below the ceiling.
These extensions are available as optional ac-
cessories and may be purchased through your
NORDYNE distributor.
10. DUCT CONNECTOR
SELECTION PLATINUM SERIES
a. For Platinum ready construction use
the 14” round duct connector, p/n:
903896.
NON-PLATINUM SERIES
a. Determine depth of fl oor cavity from
surface of fl oor to top of supply air duct
(See Figure 9).
h. Gas piping is not run in or through the return
duct system.
i. Test the negative pressure in the closet with
the air-circulating fan operating at high speed
and the closet closed. The negative
pressure is to be no more negative than minus
0.05 inch water column.
j. Air conditioning systems may require more
duct register and open louver area to ob-
tain necessary airfl ow. Use NORDYNE’s
certiduct program to determine proper duct
size for A/C.
8. AIR DISTRIBUTION SYSTEMS
For proper air distribution, the supply duct system
must be designed so that the static pressure
measured external to the furnace does not
exceed the listed static pressure rating shown
on the furnace rating plate.
Location, size, and number of registers should
be selected on the basis of best air distribution
and fl oor plan of the home.
CAUTION:
HAZARD OF ASPHYXIATION: Do not
cover or restrict return air opening.
9. ROOF JACK SELECTION
Note: Install only Roof Jack Assemblies listed
in Table 5 on this heating appliance.
a. Determine depth of ceiling cavity from center
of roof opening to center of ceiling opening.
(See Dimension “A” in Figure 6.)
b. Determine ceiling height and subtract height
of furnace. (See Dimension “B” in Figure 6.)
c. Add dimensions A + B (and X from Table 6
and Figure 7 if slant deck fl ashing is used).
The total length of (A + B + X) must be within
the minimum and maximum range of one of
the Roof Jacks listed in Table 5.
APPLICATION NOTES:
a. FAW, FAWT, SAW and SAWT Series Roof
Jacks with a 5” diameter inner vent pipe may
be used with all models of M1 Series gas and
oil furnaces.
b. F=Flat Flashing; fl exes from 0/12 to 1/12 roof
slope.
c. S=Slant Flashing. 2.5/12 Slope fl exes from
1/12 to 4/12 roof slope, 4/12 fl exes from 3/12
to 5/12.
d. Stainless steel roof jacks are available.
Table 6. Slant Deck Flashings
Table 7. Floor Cavity Sizes
Optional Deck Flashings for Flat and 2.5/12 Pitch
Roof Jacks.
(4/12 Pitch Roof Jacks not applicable.)
IF ROOF PITCH IS:
USE SLANT DECK
FLASHING NO.
“X” FACTOR IS:
“F Series Roof Jack
2” in 12”
903893 (2.5/12)
2-1/8”
2-1/2” in 12”
903893 (2.5/12)
2-1/2”
3” in 12”
903894 (3/12)
2-7/8”
3-1/2” in 12”
903894 (3/12)
3-1/4”
4” in 12”
903895 (4/12)
3-5/8”
“S” Series Roof Jack (2.5/12 Pitch only)
4-1/2” in 12”
903895 (2.5/12)
2-1/8”
5” in 12”
903895 (2.5/12)
2-1/2”
5-1/2” in 12”
903894 (3/12)
2-7/8”
6” in 12”
903894 (3/12)
3-1/4”
6-1/2” in 12”
903895 (4/12)
3-5/8”
If “X” (Floor Cavity) is:
Use Duct Connector
Model Part Number:
English
Metric (mm)
Finger Tab
Screw Down
7/8”
22
901987
904008
2”
51
901988
904009
4-1/4”
108
901989
904010
6-1/4”
159
901990
904011
8-1/4”
210
901991
904012
10-1/4”
260
901992
904013
12-1/4”
311
901993
904014
