Amana GUX-X Installation Instructions Manual page 12

structure as shown in Figures 6, 8, and 9 are not to be
counted when using Tables 1 through 3. The additional two
90° elbows as shown in Figure 7 must be counted as part
of the total number of inside elbows when using Tables 1
- 3. WHEN THE VENT SYSTEM REQUIRED IS BORDER-
LINE WITH NEXT SIZE COMBINATION CATEGORY,
USE THE NEXT LARGER SIZE.
Important: One short radius 90° elbow is equivalent to 3-
1/3 medium radius elbows. For this reason, short radius
90° elbows must not be used. The proper centerline-to-
centerline dimensions for medium radius 90° elbows are
shown below in Figure 11.
Elbow or
Coupling
Inside
Figure 11
Medium Radius Elbow Dimensions
EXAMPLE:
An installation calls for a 45,000 Btuh furnace. It must be
vented 50 inside feet and use three inside medium radius
90° elbows on both inlet and exhaust. With this in mind, we
must look at Table 1 to determine the correct vent and air
intake pipe size. With three elbows and 50 feet of straight
pipe, 3 inch air intake pipe must be used and 2 inch vent
pipe.
Important: When three inch diameter exhaust pipe is
used, the transition from two inch to three inch pipe must
be made in a vertical run. This is necessary for proper
condensate drainage and pressure switch operation.
VENT PIPE INSTALLATION
The size of the vent and air intake pipes is determined by
the heating capacity of the furnace and the length and
number of elbows of the pipe runs. To properly size the
pipes, refer to the previous section.
Use only the fittings, primer, and solvent cement which are
described in Section IV. An air intake screen is supplied
with the furnace and should be installed as shown in
Figures 6-10. Do not place a screen in the exhaust vent
termination. The furnace flue products could cause it to
corrode.
WARNING
To prevent death, personal injury or property
damage, solvent cements are combustible
liquids and should be kept away from all
ignition sources (i.e. sparks, open flames
and excessive heat). Avoid breathing cement
vapors or contact with skin and eyes.
3-1/16" Min. For 2" Pipe
4-9/16" Min. For 3" Pipe
90° Elbow
Wall Outside
To Ground
12" Min.
Under some conditions, insulation of some or all of the vent
pipe and/or combustion air pipe may be required. Do not
install insulation until after the flue system has been
inspected for leaks as described below.
WARNING
To prevent death, personal injury or
property damage due to carbon monoxide,
carefully inspect the entire flue system
both inside and outside the furnace after
installation is completed, to assure it is
properly sealed and not leaking flue gases.
For each 2 inch pipe, drill a 2-3/8 inch diameter hole
through the wall at the proper location.
For each 3 inch pipe, drill a 3-1/2 inch diameter hole
through the wall at the proper location.
Cut a piece of PVC (ABS) pipe that is the thickness of the
wall plus the depth of the sockets of the fittings to be
installed on the inside and outside of the walls.
To prevent the vent pipe from moving, and possibly dam-
aging the connections, locate the fittings on the inside wall
and the elbow on the outside as shown in Figure 11 for the
air intake.
In a basement installation, the pipes may be run between
the joist spaces. If the pipes must go below the joists, then
the pipes must run up into the last joist space to go through
the header. Two 45° elbows should be used rather than
90's. The horizontal run of exhaust pipe must not have any
sag that can hold condensate and should reach up at least
1/4 inch per foot so that condensate will run back to the unit
to drain. Support the horizontal run at least every three
feet.
Allow for some expansion and contraction from tempera-
ture fluctuations. The normal direction changes usually
account for this, but if you have a long run followed by a
short offset of less than 40 inches such as going up into the
last joist space, the pipes should be tightly clamped to
prevent flex loading on the fittings. Seal around the pipe on
the outside wall with silicone caulking material.
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