Installation Manual

Demand Duo™ H-Series Installation and Operation Manual 34
For the table below:
• Header is the main vent pipe into which sev-
eral vents connect
• Vent Length is the distance from the end of
the header to the vent termination.
• Maximum vent length starts at the end of the
header system.
• Use 10 ft (3 m) as equivalent vent length for
90° elbows.
Header
Vent Length
Common Vent Maximum Equivalent Vent Length
Rinnai Common Vent System or Schedule 40 PVC/CPVC
Water Heater
Model
# Water
Heaters
Max
System
BTU/HR
HEADER DIAMETER
3 in. 4 in. 6 in.
3 in.
Vent
Diameter
4 in.
Vent
Diameter
6 in.
Vent
Diameter
6 in.
Vent
Diameter
2 398,000 65 
150 
150 
150 
CU199i
(REU-N3237FFC-US)
3 597,000
4 796,000 65 
5 995,000
6 1,194,000
7 1,393,000 70 
8 1,592,000
CU160i
(REU-N2530FFC-US)
2 320,000 90  150 
150 
150 
3 480,000 100 
4 640,000 65 
5 800,000
6 960,000
RU130i
(REU-N2024FF-US)
2 260,000 90  150 
150 
150 
3 390,000 100 
4 520,000 65 
5 650,000
6 780,000
Figure 38