Rinnai RUC80i Installation And Operation Manual page 17

Flue Installation with Concentric Venting (indoor models only)
Install the venting termination according to the diagrams and instructions below.
Slope the venting 1/4" per foot toward the
appliance according to the vent manufacturers
installation instructions.
Dispose of condensate per local codes.
Horizontal Termination
Vertical Termination
Slope the venting 1/4" per foot toward the
appliance according to the vent manufacturers
installation instructions.
Dispose of condensate per local codes.
Securing Screw
KBD Series Manual
Secure the first vent component to the water heater
with one self-tapping screw at the hole.
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