Water Temperature Control; Preventive Maintenance; Check The Ignitor Assembly; Ignitor Assembly - A.O. Smith BTI 120 Installation & Operation Manual

WATER TEMPERATURE CONTROL

THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE
THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT
WATER TEMPERATURES REQUIRED FOR AUTOMATIC
DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD
BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/
OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS
VARIES WITH THE PERSON'S AGE AND TIME OF EXPOSURE.
THE SLOWER RESPONSE TIME OF DISABLED PERSONS
INCREASES THE HAZARDS TO THEM. NEVER ALLOW SMALL
CHILDREN TO USE A HOT WATER TAP, OR TO DRAW THEIR
OWN BATH WATER. NEVER LEAVE A CHILD OR DISABLED
PERSON UNATTENDED IN A BATHTUB OR SHOWER.
THE WATER HEATER SHOULD BE LOCATED IN AN AREA
WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO
SET TEMPERATURES.
SETTING THE WATER HEATER TEMPERATURE AT 120°F WILL
REDUCE THE RISK OF SCALDS.
require settings at specific lower temperatures.
Below you will find listed the approximate time-to-burn
relationship for normal adult skin. Short repeated heating cycles
caused by small hot water uses can cause temperatures at the
point of use to exceed the thermostat setting by up to 20°F . If you
experience this type of use, you should consider using lower
temperature settings to reduce scald hazards.
Temperature
Setting Degree Burns on Adult Skin
180°F (82°C)
170°F (77°C)
160°F (71°C)
150°F (66°C)
140°F (60°C)
130°F (54°C)
120°F (49°C)
Valves for reducing point-of-use temperature by mixing cold and
hot water are available. Also available are inexpensive devices
that attach to faucets to limit hot water temperatures. Contact a
licensed plumber or the local plumbing authority.
The water temperature is controlled by a thermostat, fig. 3, which
has two sensing elements. One sensor is located near the top
of the tank and the other is near the center. The thermostat is set
in the lowest position before the heater leaves the factory.
The thermostat temperature dial, fig. 3, is accessible by removing
the control cover. The dial is adjustable and may be set for
120°F(49°C) to 180°F(82°C) water temperature, but 120°F (49°C)
DANGER
Some states or provinces
Time to Produce 2nd & 3rd
Nearly instantaneous
Nearly instantaneous
About 1/2 second
About 1-1/2 seconds
Less than 5 seconds
About 30 seconds
More than 5 minutes
is the recommended starting point. It is suggested the dial be
placed on the lowest setting which produces an acceptable hot
water supply. This will always give the most energy efficient
operation. The temperature control has a 4°F fixed differential.

PREVENTIVE MAINTENANCE

CHECK THE IGNITOR ASSEMBLY

At least once a year, check the ignitor assembly, Fig. 12, and the
main burner, Fig. 13, for proper operation. Refer to the following
ignitor assembly and main burner sections.

IGNITOR ASSEMBLY

For access to ignitor assembly, unfasten two screws to burner
cover and remove. Locate the burner with the ignitor assembly
and remove screw holding burner to manifold. Slide burner out
to access ignitor assembly.
Servicing of the ignitor assembly includes keeping the ignitor
free of lint, scale or any other foreign debris.

MAIN BURNER

The main burner, fig.13, should display the following
characteristics:
• Cause rapid ignition and carry across entire burner.
• Give reasonably quiet operation during ignition, burning, and
extinction.
• Cause no excessive lifting of flame from burner ports.
If the preceding burner characteristics are not evident, check for
accumulation of lint, scale or other foreign debris that restricts or
blocks the air openings to the burner or heater.
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FIGURE 12
FIGURE 13