A.O. Smith BTH 120 - 250 warranty Features, Water Temperature Control, High Limit Switch E.C.O

FEATURES

IMPORTANT

IT IS REQUIRED THAT A QUALIFIED SERVICE TECHNICIAN PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME THE USER SHOULD NOT HESITATE TO ASK THE TECHNICIAN ANY QUESTIONS WHICH HE MAY HAVE IN REGARD TO THE OPERATION AND MAINTENANCE OF THE UNIT.

A CHECKLIST AND SERVICE INFORMATION section are included at the rear of this manual. By using this checklist the user may be able to make minor operational adjustments and save himself unnecessary service calls. However, the user should not attempt repairs which are not listed in this section.

WATER TEMPERATURE CONTROL

Temperature	Time to Produce 2nd & 3rd
Setting	Degree Burns on Adult Skin
180°F	Nearly instantaneous
170°F	Nearly instantaneous
160°F	About 1/2 second
150°F	About 1-1/2 seconds
140°F	Less than 5 seconds
130°F	About 30 seconds
120°F	More than 5 minutes

FIGURE 1

Valves for reducing point-of-use temperature by mixing cold and hot water are available (see Figure 2). Also available are inexpensive devices that attach to faucets to limit hot water temperatures. Contact a licensed plumber or the local plumbing authority.

DANGER

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/ ORDEATH.THETEMPERATUREAT WHICHINJURYOCCURSVARIESWITH THE PERSON’S AGE AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIMEOFDISABLEDPERSONSINCREASESTHEHAZARDSTOTHEM.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.

The water temperature is controlled using the Temperature Control Button on the Display at the front of the unit (See Figure 1). This control utilizes two temperature probes to determine the tank temperature. The primary temperature probe is located at the top of the tank and the other is near the water inlet.

The temperature may be adjusted from 80° to 180°F. The thermostat was adjusted to 120°F before the heater was shipped from the factory. It is recommended that lower water temperatures be used to avoid the risk of scalding. It is further recommended, in all cases, that the water temperature be set for the lowest temperature which satisfies your hot water needs. This will also provide the most energy efficient operation of the water heater and minimize scale formation.

SETTINGTHEWATERHEATERTEMPERATUREAT120°FWILLREDUCETHE RISK OF SCALDS. Some states require settings at specific lower temperatures.

Figure 1 shows 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.

FIGURE 2

HIGH LIMIT SWITCH (E.C.O.)

The top immersion well of the dual bulb controller also contains the high limit (energy cutoff) sensor. The high limit switch interrupts the main burner gas flow should the water temperature reach approximately 202°F.

Should the high limit switch activate, it must be manually reset by depressing the Temperature Adjustment Button/Reset Button on the display board. The water temperature must drop below 160°F before the controller can be reset.

Continued manual resetting of high limit control, preceded by higher than usual water temperature is evidence of high limit switch operation. The following are possible reasons for high limit switch operation.

•A malfunction in the thermostatic controls would allow the gas valve to remain open causing water temperature to exceed the thermostat setting. The water temperature would continue to rise until high limit switch operation.

Contact your dealer or servicer if continued high limit switch operation occurs.

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