Rheem RGFE Installation Instructions Manual page 25

FIGURE 17
STANDARD VERTICAL DIRECT VENTING
UPFLOW MODEL SHOWN (TYPICAL FOR DOWNFLOW/HORIZONTAL MODELS)
5
DETAIL A
12"
EXHAUST
TERMINATION
NOTES:
1
THE COMBUSTION AIR PIPE
MUST TERMINATE IN THE
SAME PRESSURE ZONE AS
THE EXHAUST PIPE.
2
INCREASE THE 12-IN. MINIMUM
TO KEEP TERMINAL OPENING ABOVE
ANTICIPATED LEVEL OF SNOW ACCU-
MULATION WHERE APPLICABLE.
3
WHEN 3-IN. DIAM. PIPE IS USED,
REDUCE TO 2-IN. DIAMETER BEFORE
PENETRATING ROOF. A MAXIMUM OF
18 IN. OF 2-IN. PIPE MAY BE USED
BEFORE PASSING THROUGH ROOF.
4
SUPPORT VERTICAL PIPE EVERY 6
FEET.
5
EXHAUST TERMINATION - TERMINATE
THE LAST 12 INCHES WITH 2" PVC
PIPE ON 90,000 AND 120,000 BTUH
MODELS. REDUCE AND TERMINATE
THE LAST 12 INCHES WITH 1 / " PVC
1
2
PIPE ON 60,000 THROUGH 75,000 BTUH
MODELS.
SEE DETAIL A.
5. Insulate all vent runs through
unconditioned spaces where
below-freezing temperatures are
expected with 1" thick medium
density, foil faced fiber glass or
equivalent Rubatex/Armaflex insu-
lation. For horizontal runs where
water may collect, wrap the vent
pipe with self-regulating, 3 or 5
Watt heat tape. The heat tape
must be U.L. listed and installed
per the manufacturer's instruc-
tions.
6. All piping between the furnace
and the roof or outside wall pene-
tration is 2" or 3" as specified in
Table 7. Table 7 lists the maxi-
mum allowable length for the
exhaust vent pipe and intake air
pipe for the number of elbows
used, based on the type of termi-
nation and furnace size.
7. The minimum vent length is 5
feet.
8. All piping through the roof or out-
side wall is 2". When using 3"
pipe, reduce to 2" within 18" of
the inside of the roof or outside
wall (except 120,000 BTUH
model using the RXGY-D04 or
D04A Horizontal Vent Kit).
9. Terminate the vent using one of
the following termination options.
1
2
3
4
10. Elbows must be a minimum of 15"
apart.
11. No screens may be used to cover
combustion air or exhaust.
VERTICAL TERMINATIONS
STANDARD VERTICAL TERMINA-
TIONS (See Figure 16)
Combustion Air Piping: Use two medi-
um-radius sweep elbows to keep the
inlet downward and prevent the entry of
rain. The inlet opening of the com-
bustion air termination must be a
minimum of 12" above the anticipat-
ed level of snow accumulation.
Exhaust Vent Piping: The exhaust vent
must terminate at least 12 inches
above the combustion air termination
inlet. The 2" vent pipe used to pene-
trate the roof must be reduced to 1 1/2"
PVC for the last 12" for the 60,000 and
75,000 BTUH furnace models. No
reduction of the 2" pipe is necessary for
the 90,000 through 120,000 BTUH
models. The maximum length of the
exposed vent pipe above the roof is
30".
5
5
5
ST-A0407-00
25