Installing The New Water Heater; Water Piping - A.O. Smith Power Direct ventedGasModels Instruction Manual

InstallInG the new water heater

water pIpInG

HOTTER WATER CAN SCALD:
Water heaters are intended to produce hot water. Water heated to
a temperature which will satisfy space heating, clothes washing,
dish washing, cleaning and other sanitizing needs can scald and
permanently injure you upon contact. Some people are more likely to
be permanently injured by hot water than others. These include the
elderly, children, the infirm, or physically/mentally disabled. If anyone
using hot water in your home fits into one of these groups or if there
is a local code or state law requiring a certain temperature water at
the hot water tap, then you must take special precautions. In addition
to using the lowest possible temperature setting that satisfies your
hot water needs, a means such as a mixing valve should be used at
the hot water taps used by these people or at the water heater, see
Figure 2. Valves for reducing point of use temperature by mixing cold
and hot water are also available.
Consult a Qualified Installer or Service Agency. Follow manufacturer's
instructions for installation of the valves. Before changing the factory
setting on the thermostat, read the "Temperature Regulation" section
in this manual.
This water heater shall not be connected to any heating systems or
component(s) used with a non-potable water heating appliance.
All piping components connected to this unit for space heating
applications shall be suitable for use with potable water.
Toxic chemicals, such as those used for boiler treatment shall not be
introduced into this system.
When the system requires water for space heating at temperatures
higher than required for domestic water purposes, a tempering valve
must be installed. Please refer to Figure 2 for suggested piping
arrangement.
Water supply systems may, because of code requirements or such
conditions as high line pressure, among others, have installed
devices such as pressure reducing valves, check valves, and back
flow preventers. Devices such as these cause the water system to
be a closed system.
therMal eXpansIon
As water is heated, it expands (thermal expansion). In a closed
system the volume of water will grow when it is heated. As the
volume of water grows there will be a corresponding increase in
water pressure due to thermal expansion. Thermal expansion can
cause premature tank failure (leakage). This type of failure is not
covered under the limited warranty. Thermal expansion can also
cause intermittent temperature-pressure relief valve operation:
water discharged from the valve due to excessive pressure build
up. This condition is not covered under the limited warranty. The
temperature-pressure relief valve is not intended for the constant
relief of thermal expansion.
A properly sized thermal expansion tank should be installed
on all closed systems to control the harmful effects of thermal
expansion. Contact a local plumbing service agency to have a
thermal expansion tank installed.
note: to protect against untimely corrosion of hot and cold
water fittings, it is strongly recommended that dielectric unions
or couplings be installed on this water heater when connected
to copper pipe.
All gas piping must comply with local codes and ordinances or with the
National Fuel Gas Code (ANSI Z223.1/ NFPA-54) whichever applies.
Copper and brass tubing and fittings (except tin lined copper tubing)
shall not be used.
Figure 10 shows the typical attachment of the water piping to the
water heater. The water heater is equipped with 3/4 inch NPT water
connections.
12
fIGure 10.