Rheem RGFG Installation Instructions Manual page 21

INSTALLATION – RXGY-G02A Side Wall Vent
FIGURE 11
VENT KIT INSTALLATION OPTIONS
FIGURE 12
TYPICAL INSTALLATION
For 90000 thru 120000 BTUH models-
reduce to a length between 12 inches
and 30 inches of 2 inch pipe.
Note: Vent should protrude a
maximum of 2-1/4" beyond vent plate.
Air intake should protrude a maximum
of 1 inch beyond vent plate.
Seal all wall cavities.
ST A1075
21