Installation Guide

Rinnai Tankless Water Heater Installation and Operation Manual 49
• The piping (including soldering materials) and components connected to this appliance must be
approved for use in potable water systems.
• Purge the water line to remove all debris and air. Debris will damage the water heater.
• The appliance must not be connected to a system that was previously used with a non-potable
water heating appliance.
• Ensure that the water filter on the water heater is clean and installed.
• DO NOT introduce toxic chemicals such as those used for boiler water treatment to the potable
water used for space heating.
• Verify water pressure meets requirements.
To connect the water supply, follow the instructions below.
Water connections to the water heater should follow all state and local plumbing codes. If this is a
standard installation, refer to the “Piping Diagram for Basic Installation” below.
1. Plumb the cold water supply line to the water heater on the 3/4 in. MNPT connection at the
bottom of the water heater marked “COLD.”
2. Plumb the hot water supply line to the 3/4 in. MNPT connection marked “HOT.”
3. If a pipe cover will be installed, make sure water lines to the water heater fit within the
confinements of the pipe cover.
PIPING DIAGRAM FOR BASIC INSTALLATION
KEY
This is not an engineered drawing. It is intended only
as a guide and not as a replacement for
professionally engineered project drawings. This
drawing is not intended to describe a complete
system. It is up to the contractor/engineer to
determine the necessary components and
configuration of the particular system being installed.
This drawing does not imply compliance with local
building code requirements. It is the responsibility of
the contractor/engineer to ensure installation is in
accordance with all local building codes. Confer with
local building officials before installation.
3/4" Ball Valve
3/4" Union
Check Valve
Pressure Relief
Valve
Pressure Regulator
Circulating Pump
Boiler Drain Valve
Solenoid Valve
S
Condensate
Drain
Line
Gas Supply
Cold water Supply line
Hot water Supply line
IMPORTANT
The condensate drain pipe (along its entire
length) must be at least the same diameter
as the drain line (1/2 in. NPT).
Refer to section “4.9 Connect Condensate
Drain” for more information.
Figure 46