Rheem RTGH Owners Manual

37
INSTALLATION INSTRUCTIONS
Venting for Direct-Vent Water Heater
The unit may be vented horizontally through a wall or
vertically through the roof. Pipe runs must be adequately
supported along both vertical and horizontal runs.
Maximum unsupported span is recommended to be
no more than 4 feet (1.2 m). It is imperative that the first
hanger be located on the horizontal runs immediately
adjacent to the first 90-degree elbow from the vertical
rise. Only use support isolation hanging bands. DO
NOT use wire to support pipe runs.
Stress levels in the pipe and fittings can be significantly
increased by improper installation. If rigid pipe clamps
are used to hold the pipe in place, or if the pipe cannot
move freely through a wall penetration, the pipe may
be directly stressed, or high thermal stresses may be
formed when the pipe heats up and expands. Install
accordingly to minimize such stresses.
NOTICES:
• It is recommended that the air intake pipe and exhaust
pipe have a 1/4" per foot upward slope toward the
outdoors.
• Maintain the proper clearance between the vent pipe
and combustible or noncombustible materials as
described on page 29.
• A clearance of 0 in. (0 cm) is allowed between the vent
or air intake pipe and combustible material.
• Use proper support for the vent and air intake pipes.
• It is recommended the support method used isolates the
vent pipe from floor joists or other structural members.
This helps prevent transmission of noise and vibration.
• DO NOT support, pin, or otherwise secure the venting
system in a way that restricts the normal thermal
expansion and contraction of the chosen venting
material.
See page 38 for additional requirements for the
Commonwealth of Massachusetts.
Preexisting Venting Notes:
If the water heater is being installed as a replacement
for an existing water heater, a thorough inspection of
the existing venting and air intake system must be
performed prior to any installation work. Verify that the
correct materials, vent lengths, and terminal locations
as described in this manual have been met. Carefully
inspect the entire venting and air intake system for any
signs of cracks or fractures, particularly at the joints
between elbows or other fittings and the straight runs
of vent pipe. Check the system for signs of sagging or
other stresses in the joints as a result of misalignment
of any components in the system. If any of these
conditions are found, they must be corrected in
accordance with the venting instructions in this manual
before completing the installation and putting the water
heater into service.