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FIGURE 13.
• Louvers and Grilles: In calculating free area, consideration
shall be given to the blocking effect of louvers, grilles or
screens protecting openings. Screens used shall not be
smaller than 1/4 inch (6.4 mm) mesh. If the free area through
a design of louver or grille is known, it should be used in
calculating the size opening required to provide the free area
specified. If the design and free area is not known, it may be
assumed that wood louvers will be 20-25 percent free area
and metal louvers and grilles will have 60-75 percent free
area. Louvers and grilles shall be fixed in the open position
or interlocked with the equipment so that they are opened
automatically during equipment operation.
• Special Conditions Created by Mechanical Exhausting or
Fireplaces: operation of exhaust fans, ventilation systems,
clothes dryers or fireplaces may create conditions requiring
special attention to avoid unsatisfactory operation of installed
gas utilization equipment.
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 handicapped. 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, shall be used at the hot water
taps used by these people or at the water heater. Mixing valves
are available at plumbing supply or hardware stores, see
Figure 14 below. Valves for reducing point of use temperature
by mixing cold and hot water are also available. 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.
FIGURE 14.
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.
Water supply systems may, because of such events as high
line pressure, frequent cut-offs or the effects of water hammer
among others, have installed devices such as pressure reducing
valves, check valves, back flow preventers, etc. to control these
types of problems. When these devices are not equipped with
an internal by-pass, and no other measures are taken, the
devices cause the water system to be closed. As water is heated,
it expands (thermal expansion) and closed systems do not allow
for the expansion of heated water.
The water within the water heater tank expands as it is heated
and increases the pressure of the water system. If the relieving
point of the water heater’s temperature-pressure relief valve is
reached, the valve will relieve the excess pressure. The
temperature-pressure relief valve is not intended for the
constant relief of thermal expansion. This is an unacceptable
condition and must be corrected. It is recommended that any
devices installed which could create a closed system have a
by-pass and/or the system have an expansion tank to relieve
the pressure built by thermal expansion in the water system.
Refer to the Thermal Expansion section under Troubleshooting
Guide or contact local plumbing authority or local Sears Service
Center on how to control this situation.
NOTE: To protect against untimely corrosion of hot and cold
water fittings, it is strongly recommended that di-electric
unions or couplings be installed on this water heater when
connected to copper pipe.