Rheem 801T Series Installation Instructions Manual page 18

COMBUSTION AND VENTILATION AIR (cont .)
It is also acceptable to run the condensate drain (or refrig-
erant) line access over the air intake hole as long as a 1"
minimum clearance is maintained .
Combustion air openings must not be restricted in any manner .
IMPORTANT: When indoor combustion air is used, the inlet
air opening at the furnace must be protected from accidental
blockage .
IMPORTANT: If the furnace is in a location with an exhaust fan,
there must be sufficient ventilation to prevent the exhaust fan
from creating a negative pressure in the room.
Combustion air openings must NOT BE RESTRICTED in any
manner .
CONSULT LOCAL CODES FOR SPECIAL REQUIREMENTS .
B: Method 3
For the optimum in quiet operation, attic air may be brought di-
rectly to the furnace .
IMPORTANT: In applications using Method 3 for combustion air,
the attic must be ventilated by gable or soffit vents .
FIGURE 14
COMBUSTION AIR FITTING – OPTIONAL ATTIC COMBUSTION AIR PULL
CAUTION
!
USE OF SHEET METAL
AIR INTAKE PIPE INSTEAD
OF PVC MAY RESULT IN
NOISE ISSUES .
18
ATTACH A 90° ELBOW TO TOP INLET AIR
OPENING TO PREVENT ACCIDENTAL BLOCKAGE
OF INTAKE OPENING .
12" MIN . FROM
TOP OF INSULATION
10 FT . MAX .
INCLUDING
HORIZONTAL DIRECTION
#8 SCREW
CAUTION
!
COMBUSTION AIR INTAKES CANNOT BE TERMINATED
OUTSIDE . DOING SO CAN CAUSE IMPROPER OPERA-
TION OF THE FURNACE .
COMBUSTION AIR FROM ATTIC
If attic combustion air is used, the inlet air opening at the fur-
nace must be protected from accidental blockage . Install a 90°
elbow pointing horizontally at the top of inlet air pipe . See Figure
14 (maximum of 2, 45° or 90° elbows, allowed) .
NOTE: Maximum length of pipe that may be used for combus-
tion air is 10 feet with two elbows . Lengths of more than 10 feet
can result in nuisance pressure switch trips .
PVC
ELBOW
EXHAUST
ATTIC SPACE
INSULATION
METAL FLUE PIPE ONLY
INDOOR SPACE
6" MINIMUM
CLEARANCE
PVC
COUPLER
#8 SCREWS