Air" In Hot-Water Faucets; High Water Temperature Shut-Off System - A.O. Smith RESIDENTIAL GAS WATER HEATERS Installation And Operating Manual

"AIR" IN HOT-WATER FAUCETS

• Flammable hydrogen gases may
be present.
• Keep all ignition sources away
from faucet when turning on hot
water.
HYDROGEN GAS: Hydrogen gas can be produced in
a hot-water system that has not been used for a long
period of time (generally two weeks or more). Hydrogen
gas is extremely fl ammable and explosive. To prevent
the possibility of injury under these conditions, it is
recommended that the hot-water faucet, located farthest
away, be opened for several minutes before any electrical
appliances which are connected to the hot-water system
are used (such as a dishwasher or washing machine). If
hydrogen gas is present, there will probably be an unusual
sound similar to air escaping through the pipe as the hot-
water faucet is opened. There must be no smoking or open
fl ame near the faucet at the time it is open.

HIGH WATER TEMPERATURE SHUT-OFF SYSTEM

This water heater is equipped with a manual reset type
high limit (Thermal Cut Out (TCO)) sensor. The high limit
switch interrupts the main burner gas fl ow should the
water temperature reach 195°F (91°C). The high limit
can be reset when the water temperature drops below
140°F (60°C).
Note: See "TCO Resettable Lockout" for corrective action
and how to reset the control.
WARNING
Explosion Hazard
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