Mixing Valves - American Water Heater 300 Series Instruction Manual

DEDICATED POWER WIRING AND BREAKERS
Dedicated power supply wires, ground wiring and dedicated
circuit breakers often prevent electrical line noise and should
be considered when installing the water heater.
NOTE: This water heater should not be connected to an electrical
supply with a Ground Fault Circuit Interrupter (GFCI) or Arc Fault
Circuit Interrupter (AFCI) with Integral GFCI protection as defined
in NFPA 70, CSA C22.1 and UL 943.
POWER FLUCTUATIONS AND ELECTRICAL NOISE
The water heater 's control system requires a source of
stable clean electricity for proper operation. Connecting
the water heater to a branch circuit that is subject to
fluctuations in voltage level or electrical line noise such as
EMI (electro magnetic interference) or RFI (radio frequency
interference) may cause erratic control system operation
and malfunction.
A high quality power supply filter/suppressor must be
installed if the above conditions exist. Call the technical
support phone number listed on the back cover of this
manual for more information.
NOTE: Malfunctions caused by the power supply and the
costs to install power supply filters are not covered under
the limited warranty.

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 4 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 9) 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.
In all cases, the following burn table must be used.
Water Temperature Time for 1st Degree Burn
°F (°C)
(Less Severe Burns)
110 (43.3) (normal shower temp.)
116 (46.7)
116 (46.7)
122 (50)
131 (55)
140 (60)
149 (65)
154 (67.8)
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15, 1978)
19
Table 4
Time for Permanent
Burns
2nd & 3rd Degree
(Most Severe Burns)
(pain threshold)
35 minutes 45 minutes
1 minute 5 minutes
5 seconds 25 seconds
2 seconds 5 seconds
1 second 2 seconds
instantaneous 1 second