Dunkirk GWB9-050IH-2 Installation Instructions Manual page 27

Figure 18 - Combustion Air and Vent Piping - Boiler Connections
COMBUSTION AIR AND VENT PIPE
27
2" (50.8mm) DIAMETER VENT AND
COMBUSTION AIR INTAKE PIPING
- 21 feet maximum total equivalent
length for 90-100 models
-26 feet maximum total equivalent
length for 90-50 and -90-75 models
- 2 feet minimum total equivalent
length for all models
TRANSITION FITTING
2" (50.8mm) ⊘ to 3" (76.2mm)
⊘ IN VERTICAL RUN
3" (76.2mm) DIAMETER VENT AND
COMBUSTION AIR INTAKE PIPING
- 92 feet maximum total equivalent length
for 90-100 models
- 15 feet minimum total equivalent length
for 90-100 models
- 112 feet maximum total equivalent length
for 90-50 and 90-75 models
- 20 feet minimum total equivalent length
for 90-50 and 90-75 models