Installing The New Water Heater; Chemical Vapor Corrosion; Water Piping; Space Heating & Potable Water System - A.O. Smith 120 Series Instruction Manual

INSTALLING THE NEW WATER HEATER

CHEMICAL VAPOR CORROSION

CORROSION OF THE FLUEWAYS AND VENT SYSTEM MAY
OCCUR IF AIR FOR COMBUSTION CONTAINS CERTAIN CHEMICAL
VAPORS. SUCH CORROSION MAY RESULT IN FAILURE AND
RISK OF ASPHYXIATION.
Spray can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium and
sodium chloride (water softener salt), waxes, and process chemicals
are typical compounds which are potentially corrosive.
Do not store products of this sort near the heater. Also, air which is
brought in contact with the heater should not contain any of these
chemicals. If necessary, uncontaminated air should be obtained from
remote or outside sources. The limited warranty is voided when failure
of water heater is due to a corrosive atmosphere. (See limited warranty
for complete terms and conditions).

WATER PIPING

DANGER
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 handicapped.
If anyone using hot water 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 lowest possible temperature setting that satisfies your hot water
needs, a means such as a mixing valve, should be used at 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 valves. Before changing the factory setting
on thermostat, read "Temperature Regulation" section in this manual.
Water temperature over 125°F (52°C)
can cause severe burns instantly
resulting in severe injury or death.
Children, the elderly and the physically
or mentally disabled are at highest
risk for scald injury.
Feel water before bathing or showering.
Temperature limiting valves are
available.
Read instruction manual for safe
temperature setting.
This water heater should 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 should be suitable for use with potable water.
Toxic chemicals, such as those used for boiler treatment should not
be introduced into this system.
When the system requires water for space heating at temperatures
higher than required for domestic water purposes, a mixing
valve must be installed. Please refer to Figure 2 for suggested
piping arrangement.
This water heater cannot be used in space heating applications only.
SPACE HEATING AND POTABLE WATER SYSTEM
This appliance has been design certified as complying with
American National Standard/CSA Standard for water heaters and is
considered suitable for Water (Potable) Heating and Space Heating.
Your water heater is equipped with inlet /outlet connections
for use in space heating applications (see Figure 2). If this
water heater is to be used to supply both space heating and
potable (drinking) water, the instructions listed below must
be followed:
• Be sure to follow the manual(s) shipped with the air handler or other
type heating system.
• This water heater is not to be used as a replacement for an existing
boiler installation.
• Do not use with piping that has been treated with chromates, boiler
seal or other chemicals and do not add any chemicals to the water
heater piping
• If the space heating system requires water temperatures in
excess of 120°F (49°C), a mixing valve must be installed per the
manufacturer's instructions in the potable hot water supply to limit
the risk of scald injury.
• Pumps, valves, piping and fittings must be compatible with
potable water.
• A properly installed flow control valve is required to prevent
thermosiphoning. Thermosiphoning is the result of a continuous
flow of water through the air handler circuit during the off cycle.
Weeping (blow off) of the temperature and pressure relief valve
(T & P) or higher than normal water temperatures are the first signs
of thermosiphoning.
• The hot water line from the water heater should be vertical past
any mixing valve or supply line to the heating system to remove air
bubbles from the system.
• Do not connect the water heater to any system or components
previously used with non-potable water heating appliances when
used to supply potable water.

CLOSED WATER SYSTEMS

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.
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