Installation Guide

Rinnai Tankless Water Heater Installation and Operation Manual 51
To prevent condensate damage, follow these
guidelines:
• Do not plumb the condensate drain
with the pressure relief valve; both
must be plumbed independently to
drain.
• All condensate must drain and be
disposed of according to local codes.
• Use only corrosion resistant
materials for the condensate drain
lines such as PVC pipe or plastic
hose.
• The condensate drain pipe (along its
entire length) must be at least the
same diameter as the drain line (1/2
in. MNPT).
• Condensation drain lines installed in
areas that are subject to freezing
temperatures should be wrapped
with an approved supplemental heat
source. Install per manufacturer’s
instructions.
• Slope the condensate drain lines
toward the inside floor drain or
condensate pump.
• The end of the condensate drain
pipe should be open to the
atmosphere. The end should not be
under water or other substances.
• For external (outdoor) installations, to
minimize freezing of the condensate, run
the condensate drain line through an
interior wall or between insulation and an
interior wall.
• If a floor drain is not available or the drain
is above the level of the condensate drain,
a condensate pump should be installed.
• A condensate neutralizer kit (part number
804000074) is available from Rinnai. The
kit allows condensate to flow through
neutralizing media that raises the pH of the
condensate to a level that will help prevent
corrosion of the drain and public sewer
system. Refer to section “3.6 Accessories”
for more information.
• The condensate drain pipe should be as
short as possible and have a downward
pitch.
• Pour approximately 10 ounces (1.25 cups)
of water directly into the water heater’s
exhaust port.
• DO NOT connect the condensate drain line
with an air conditioning evaporator coil
drain.
• Water heaters have an
integrated condensate trap.
DO NOT install an external
condensate trap.
CORRECT NOT CORRECT
Pipe submerged
in water
Pipe open to
atmosphere
Water
Level
Water
Level
Figure 47
Figure 48
Pipe open to
atmosphere
Condensate pump
*Overflow bypass
Air Gap
* Safety overflow if condensate drain
becomes clogged.