Lochinvar RPD-I-S User Manual page 19

Venting continued-
THROUGH THE WALL VENTING WITH LOW GROUND CLEARANCE:
When venting cannot exit through the wall at a height greater than or equal to
12" (30.5 cm) above the ground, or anticipated snow level, the installation must
be modified as shown below (see Figure 8). Refer to Table 3 for maximum
venting lengths using 3" (7.6 cm) vent pipe or Table 4 for maximum lengths
using 4" (10.2 cm) vent pipe. The exhaust and intake terminals must not be
less than 16 in. (40.6 cm) apart (see figure 4a).
3" VENT
INSTALLATION
4" VENT
INSTALLATION
Figure 8
19 RPD-I-S Rev A