Installation Considerations; Instruction Manual; Closed Water Systems; Thermal Expansion - A.O. Smith 100 Series Service Handbook

INSTALLATION CONSIDERATIONS

This section of the Service Manual covers some of the critical installation requirements that, when overlooked,
often result in operational problems, down time and needless parts replacement. Costs to correct installation
errors are not covered under the limited warranty. Ensure all installation requirements and instructions
contained in the Instruction Manual that came with the Boiler have been followed prior to performing any
service procedures.

INSTRUCTION MANUAL

Have a copy of the Instruction Manual that came with the Boiler on hand for the Model and Series number
being serviced. Installation information given in this Service Manual is not a complete installation instruction.
Installation information given in this manual has a limited focus as it applies to servicing the Boiler. This
Service Manual does not replace or supersede the Instruction Manual that came with the Boiler. Always refer
to the Instruction Manual for complete installation instructions. If the Instruction Manual is not on hand, copies
can be obtained from the manufacturers web site or by calling the toll free support phone number shown on
the back cover of this manual.

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.

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 must 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.

AIR REQUIREMENTS

Carefully review the requirements for combustion and ventilation air in the Instruction Manual that came with
the Boiler. Failure to meet these requirements when the Boiler is installed or overlooking their importance
when servicing the Boiler often results in needless down time, unnecessary parts replacement, and customer
dissatisfaction.
An inadequate supply of air for combustion and ventilation often causes operational problems. A lack of
combustion and ventilation air can create a negative ambient air pressure in the installed space which can
lead to improper combustion and operational problems with pressure switches.

CONTAMINATED AIR

Combustion air that is contaminated can greatly diminish the life span of the Boiler and its components such
as Igniters and Burners. Propellants of aerosol sprays, beauty shop supplies, water softener chemicals and
chemicals used in dry cleaning processes that are present in the combustion, ventilation or ambient air can
cause such damage.
Vapors from volatile compounds such as solvents, cleaners, chlorine based chemicals and refrigerants in
addition to being highly flammable in many cases, can also react to form highly corrosive substances such as
hydrochloric acid inside the combustion chamber. The results can be hazardous and cause product failure.
If the Boiler is installed in laundries with dry cleaning equipment, it is imperative the Boiler be installed in a
Direct Vent configuration so that air for combustion is derived directly from the outdoor atmosphere through a
sealed intake air pipe. See the venting installation section in the Instruction Manual that came with the Boiler
for more information on Direct Vent installations.
4 Servicing should only be performed by a Qualified Service Agent