User Guide
18 Page
-Exhaust vent (ABS, PVC, CPVC, or polypropylene vent)-
The Indoor model can be vented with ABS, PVC, CPVC, or polypropylene (temperature rated up to at
least 149 °F). Vent material certified to ULC S636 standards is recommended in the USA. In Canada,
plastic venting must be certified to ULC S636 standards.
Item Material United States Canada
Exhaust pipe and
Fittings
Schedule 40 PVC ANSI/ASTM D1785
ULC S636 Certified
Materials Only
PVC-DWV ANSI/ASTM D2665
Schedule 40 CPVC ANSI/ASTM F441
Schedule 40 ABS-DWV ANSI/ASTM D2661
Polypropylene UL-1738
Pipe Cement/Primer
PVC ANSI/ASTM D2564
CPVC ANSI/ASTM F493
ABS ANSI/ASTM D2235
Use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel®
(polyphenylsulfone) in non-metallic venting systems is prohibited.
Covering non-metallic vent pipe and fittings with thermal insulation is prohibited.
The maximum length of exhaust vent piping must not exceed 70 ft (21.3 m) for 3 inch venting,
which depends on the elevation where the water heater is installed, and 100 ft (30.5 m) for 4
inch venting (deducting 5 ft (1.5 m) for each elbow used in the venting system). Do not use more
than 5 elbows. See the table below.
When the horizontal vent run exceeds 5 ft (1.5 m), support the vent run at 3 ft (0.9 m) intervals
with overhead hangers.
*For each elbow added, deduct 5 ft (1.5 m) from max. vent length.
For details on the vent connection, refer to pp. 19 to 22.
Vertical or Horizontal (Total) Vent Length
No. of
Elbows*
2" venting 3" venting 4" venting
0 to 3,000 ft
(0 to 914 m)
0 to 3,000 ft
(0 to 914 m)
3,001 to 6,000 ft
(915 to 1,829 m)
6,001 to 10,100 ft
(1,830 to 3,078 m)
0 to 10,100 ft
(0 to 3,078 m)
0 6.5 ft (2.0 m) 70 ft (21.3 m) 40 ft (12.2 m) 25 ft (7.6 m) 100 ft (30.5 m)
1 1.5 ft (0.5 m) 65 ft (19.8 m) 35 ft (10.7 m) 20 ft (6.1 m) 95 ft (29.0 m)
2 N/A 60 ft (18.3 m) 30 ft (9.1 m) 15 ft (4.6 m) 90 ft (27.4 m)
3 N/A 55 ft (16.8 m) 25 ft (7.6 m) 10 ft (3.0 m) 85 ft (25.9 m)
4 N/A 50 ft (15.2 m) 20 ft (6.1 m) N/A 80 ft (24.4 m)
5 N/A 45 ft (13.7 m) N/A N/A 75 ft (22.9 m)
Excludes vent terminators, one termination elbow, or rain caps.
Installaon
Installaon Manual