Rinnai Tankless Water Heater Installation and Operation Manual
48
3. Common Vent
(Indoor Units Only. Direct Vent and Non-Direct/Room Air Vent)
Common venting allows multiple Rinnai Tankless Water Heaters to share the same vent system. Rinnai
water heaters can only be common vented with Schedule 40 PVC/CPVC or with the Rinnai certified
common vent system.
Figure 47: Example: Rinnai Common Venting
Figure 48: Example: Schedule 40 PVC/CPVC
Common Venting
General Guidelines
When installing common vent, follow these guidelines:
•
Use only the materials listed in this manual
for vent, air intake pipe, and fittings. Failure to
comply with this warning could result in prop
-
erty damage, personal injury, or death.
•
When cutting vent components, ensure that
the cuts are straight.
•
Chamfer and deburr all edges before install
-
ing the components.
•
Vent joints must not leak. Confirm gas tight
connections of every vent joint.
•
Before operating the water heater(s), ensure
vent system is clean and free of debris.
•
Vent system must be supported according to
the vent manufacture’s installation instruc
-
tions.
•
Venting should be as direct as possible with a
minimum number of fittings.
•
The common vent system must only be in
-
stalled by a trained and qualified professional.
Common Vent Termination Clearances
•
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.
•
Refer to section “4.5 Vent the Water Heater”
for additional clearance requirements specific
to the installation application.
•
DO NOT slope the combustion air pipe
toward unit. Failure to comply with this
warning could result in property damage,
personal injury, or death.
•
DO NOT apply PVC/CPVC glues,
solvents, or cleaners to the tankless
water heater’s intake or exhaust gasket
connections. Failure to correctly assem
-
ble the components according to these
instructions may result in property dam
-
age, personal injury, or death.
•
DO NOT obstruct combustion air flow or
exhaust gas flow in the venting system.
•
DO NOT install the water heater in an
area with negative air pressure.
•
DO NOT combine the common vent
system with existing vents, chimneys,
or vent pipes connected to other water
heaters, boilers or appliances.
•
DO NOT common vent different Rinnai
models in a single common vent system.
•
DO NOT use cellular core PVC/CPVC,
Radel, ABS or galvanized materials.
•
DO NOT combine vent components from
different manufacturers.
WARNING
