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Common Venting | Direct Vent - Polypropylene Common Venting | Room Air - Polypropylene
COMMON VENT MAXIMUM EQUIVALENT VENT LENGTH RINNAI COMMON VENT SYSTEM OR SCHEDULE  PVC / CPVC
Water Heater Model # Water Heaters Max System BTU/HR
Header Diameter
3" 4" 6"
3" Vent Diameter 4" Vent Diameter 6" Vent Diameter 6" Vent Diameter
CU199i
(REU-N3237FFC-US)
2 398,000 65 ft
150 ft
150 ft
150 ft
3 597,000
4 769,000 65 ft
5 995,000
6 1,194,000
7 1,393,000 70 ft
8 1,592,000
9 1,791,000
90 ft
10 1,990,000
11 2,189,000
41 ft
12 2,388,000
CU160i
(REU-N2530FFC-US)
2 320,000 90 ft 150 ft
150 ft
150 ft
3 480,000 100 ft
4 640,000 65 ft
5 800,000
6 960,000
COMMON VENT MAXIMUM  
EQUIVALENT VENT LENGTHS
For the table below:
• Header is the main vent pipe into which several 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.
• For use with CU160i and CU199i (indoor) tankless water heaters only.
INLINE and CORNER 
(P/N: 790131)
Vent termination per ANSI Z223.1/NFPA 54. For clearances not 
specified in ANSI Z223.1/NFPA 54, clearances are in accordance 
with local installation codes and the requirements of the gas supplier.
*PPS material 
listed to 
ULC-S636 
for Canadian 
Installations
SAMPLE VERTICAL TERMINATION ASSEMBLY  ROOM AIR
STARTER KIT 
6" - 790138 / *791020PPS
4" - 790137
BRACKET
6" - 790092
4" - 790091
3" - 790123
ROOF TERMINATION
6" - 790096 / *791030PPS
4" - 790095
3" - 790125
° ELBOW 
6" - 790087 / 
  *791027PPS 
4" - 790027 
3" - 790121 
7' MAXIMUM VERTICAL
DISTANCE BETWEEN
BRACKETS. AT LEAST ONE
BRACKET IS REQUIRED FOR
EACH EXTENSION.
 INCH EXTENSION 
6" -  / *PPS
4" - 
3" - 
BACKTOBACK KIT 
6" - 790141 / *791022PPS
4" - 790143
4" INLINE
4" ADD-ON 
(P/N: 790139)
4" STARTER 
(P/N: 790137)
4" BACK-TO-BACK
4" ADD-ON 
(P/N: 790143)
4" STARTER 
(P/N: 790137)
6" INLINE
6" ADD-ON 
(P/N: 790140)
6" STARTER 
(P/N: 790138)
6" BACK-TO-BACK
6" ADD-ON 
(P/N: 790141)
6" STARTER 
(P/N: 790138)
"
"
"
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VENTING KITS










