American Water Heater BCG3 - Manual (Page 12)

12
water temperature control and mixing ValVes
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 devices such as
mixing valves must be installed
when required by codes and to
ensure safe temperatures at fixtures.
Water heated to a temperature which will satisfy clothes
washing, dish washing, and other sanitizing needs can scald
and cause permanent injury upon contact. Short repeated
heating cycles caused by small hot water uses can cause
temperatures at the point of use to exceed the water heater’s
temperature setting by up to 20°f (11°C).
Some people are more likely to be permanently injured by
hot water than others. These include the elderly, children, the
infirm and the physically/mentally disabled. Table 6 shows
the approximate time-to-burn relationship for normal adult
skin. if anyone using hot water provided by the water heater
being installed fits into one of these groups or if there is a
local code or state law requiring a certain water temperature
at the point of use, then special precautions must be taken.
in addition to using the lowest possible temperature setting
that satisfies the demand of the application a mixing Valve
should be installed at the water heater (see figure 10) or at the
hot water taps to further reduce system water temperature.
mixing valves are available at plumbing supply stores. Consult
a qualified installer or Service Agency. follow mixing valve
manufacturer’s instructions for installation of the valves.
taBle 6.
Water Temperature
Time to Produce 2nd & 3rd
Degree Burns on Adult Skin
180°f (82°C) Nearly instantaneous
170°f (77°C) Nearly instantaneous
160°f (71°C) About 1/2 second
150°f (66°C) About 1-1/2 seconds
140°f (60°C) Less than 5 seconds
130°f (54°C) About 30 seconds
120°f (49°C) More than 5 minutes
gas pressure reQuirements
All models require a minimum gas supply pressure of 5.2”
W.C. The minimum supply pressure is measured while gas
is not flowing (static pressure) AND while gas is flowing
(dynamic pressure). The supply pressure (static and dynamic)
should never fall below 5.2” W.C. The supply pressure should
be measured with all gas fired appliances connected to the
common main firing at full capacity. if the supply pressure
drops more than 1.5” W.C. as gas begins to flow to the water
heater then the supply gas system including the gas line and/
or the gas regulator may be restricted or undersized. See
Supply Gas Regulator section and Gas Piping section of this
manual. The low gas pressure switch will shut down the water
heater if the supply gas pressure drops below the minimum
allowable value.
The gas valve on all models has a maximum gas supply
pressure limit of 14" W.C. if a supply gas regulator is
installed on the gas supply line, the maximum recommended
pressure for the regulated gas supply is 11" W.C. The
maximum supply pressure is measured while gas is not
flowing (static pressure) AND while gas is flowing (dynamic
pressure).
supply gas regulator
The water heater covered by this manual may require the
installation of a supply gas regulator. if the supply gas pressure
exceeds 14 inches W.C. a supply gas regulator must be used.
if the gas supply pressure exceeds 14" W.C. in a multiple
water heater installation, each water heater must have its
own supply gas regulator. if required, the supply gas regulator
shall be rated at or above the Btu/hr input rating of the water
heater it supplies. if a supply gas regulator is installed on the
gas supply line, the maximum recommended pressure for the
regulated gas supply is 11" W.C.
Supply gas regulators shall have inlet and outlet connections
not less than the minimum supply gas line size for the water
heater they serve as shown in Table 9. The maxitrol 325-7L or
equivalent is recommended.
power supply
The water heaters covered in this manual require a 120
VAC, 1Ø (single phase), 60Hz, 15 amp power supply and
must also be electrically grounded in accordance with local
codes or, in the absence of local codes, with the National
electrical Code, ANSi/NfPA 70 or the Canadian electrical
Code, CSA C22.1.
installation reQuirements