Use and Care Manual

DANGER:
Failure to properly vent the water heater to the outdoors 
as outlined in this Venting section will result in death or 
serious personal injury. To avoid the risk of fire, explosion, 
or asphyxiation from carbon monoxide, NEVER operate the 
water heater unless it is properly vented and has adequate 
air supply for proper operation as outlined in this Venting 
section. This water heater must have air supply connected 
and terminated to the outdoors.
WARNING:
Refer to page 29 for required clearances to combustible 
materials. Improper clearances can cause explosion or fire 
resulting in death, personal injury, and/or product damage.
CAUTIONS:
• 
Check to make sure flue gases DO NOT recirculate into the 
air intake terminal when using direct venting. If the water 
heater is having service issues, flue recirculation may be a 
contributing factor. 
• Even when the minimum vent terminal separation 
distances are followed, recirculation may still occur 
depending upon the location outside the building, the 
distance from other buildings, proximity to corners, 
weather conditions, wind patterns, and snow depth. 
• Periodically check to make sure that flue recirculation 
is not occurring. Signs of flue gas recirculation include 
frosted or frozen intake terminals and condensate in the 
intake terminal and venting system. 
• Correction to flue recirculation may involve angling the 
intake away from the exhaust terminal and increasing the 
distance between them. Check to be sure the intake and 
exhaust terminals are not obstructed, especially during 
periods of below-freezing weather.
Venting Requirements
The installation of venting must comply with national 
codes, local codes, and the vent manufacturer’s 
instructions.
The vent exhaust and air intake must terminate outside 
as described in these instructions. DO NOT vent this 
water heater through a chimney. It must be vented 
separately from all other appliances.
NOTICE:
The unit can be vented using only the following approved 
vent pipe material. 
Use only 2 or 3 inch diameter pipe. Refer to local codes 
for restrictions on the use of InnoFlue® PP, PVC, CPVC, 
or ABS pipe and fittings. All exhaust venting materials for 
product installed in Canada must meet ULC-S636. 
The use of cellular core PVC (ASTM F891), cellular 
core CPVC, or Radel® (polyphenolsulfone) in non-
metallic venting systems is prohibited and that 
covering non-metallic vent pipe and fittings with 
thermal insulation is prohibited.
This water heater requires a special venting system. 
Refer to venting supplier’s instruction for complete parts 
list and method of installation. The manufacturers and 
product lines listed on the following tables have been 
tested and authorized to safely operate with Rheem 
tankless water heater. 
Approved Vent Materials, Fittings and Terminations:
ABS is not permitted for exhaust vent in Canada
Approved Polypropylene Vent Manufacturer/Trade Name:
*Refers to variations in nominal size.  
DO NOT USE Schedule 20, Cell Core, Drain Pipe, 
Galvanized, Aluminum, B-Vent, or any flexible vent.
34
INSTALLATION INSTRUCTIONS
Venting for Direct-Vent Water Heater
Venting
Acceptable Materials 
for Exhaust
Acceptable Materials 
for Air Intake 
Fittings 
Terminations 
(Manufactured 
by Polytech)
Schedule 40, 
ASTM D-1785
Schedule 40, 
ASTM D-1785, 
and DWV, 
ASTM-D2665
Schedule 40, 
ASTM D-2665
RXGY-G01
RXGY-G02
PTX-129
RXGY-E03A
RXGY-G01C
PVC
Schedule 40, 
ASTM F-441
Schedule 40, 
ASTM F-441, 
and CPVC 4120, 
ASTM-D2846
Schedule 40, 
ASTM F-438
CPVC
Schedule 40, 
ASTM D-2661
Schedule 40, 
ASTM D-2661 
Schedule 40, 
ASTM D-2661
ABS
Manufacturer
Trade Name
Single Wall Pipe
Elbow
Adapter
Non-Return Valve (NRV)
Siphon
Termination
Centrotherm
InnoFlue®
ISVL**** or ISVL****UV
ISELL**** or ISELL****UV
ISAAL0202
ISNRV****
IASJBVS
ISLPT**** or ISTT****










