6.To turn the heater off, open the electrical disconnect switch. If the heater is to remain inoperative for a long period of time, close the shutoff valve on the oil supply line.

WATER TEMPERATURE CONTROL

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 OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS VARIES WITH THE PERSONS AGE AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIME OF CHILDREN, AGED OR 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 TEMPERATUREAT 120°F (48.9°C) WILL REDUCE THE RISK OF SCALDS. Some states require settings at specific lower temperatures.

Figure 16 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.

Temperature

Time to Produce 2nd & 3rd

Setting

Degree Burns on Adult Skin

180°F (82.2°C)

Nearly instantaneous

170°F (76.6°C)

Nearly instantaneous

160°F (71.1°C)

About 1/2 second

150°F (65.5°C)

About 1-1/2 seconds

140°F (60.0°C)

Less than 5 seconds

130°F (54.4°C)

About 30 seconds

120°F (48.9°C)

More than 5 minutes

 

 

 

FIGURE 16

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. 17, 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.

and may be set for 120° (48.9°C) to 180°F (82.2°C) water temperature, but 120°F (48.8°C) is the recommended starting point. It is suggested the dial be placed in 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 (2.2°C) fixed differential.

HIGH LIMIT SWITCH (E.C.O)

The dual bulb controller (fig.17) contains the high limit (energy cutoff) sensor. The high limit switch interrupts main burner gas flow should the water temperature reach 195°F (90.5°C).

In the event of high limit switch operation, the appliance cannot be restarted unless the water temperature is reduced by 20°F (11.1°C)(approx.) and the high limit reset button on front of limit control (fig.17) is depressed.

Continued manual resetting of high limit control, preceded by higher than usual water temperature is evidence of high limit switch operation. Contact your dealer or servicer if continued high limit switch operation occurs.

DUAL-BULB THERMOSTAT (COVER REMOVED)

FIGURE 17

BURNER CERTIFICATE (COMBUSTION TEST)

The Commercial Standard CS75 Oil Burner Certificate form must be filled in and posted in the vicinity of the water heater.

Instructions for filling in certificate are on the back of the certificate. This must be done by the installer at the time the heater is first operated. The certificate is in the oil burner manual.

SELF-CLEANING ELIMINATOR

These units include a self-cleaning eliminator installed in the front water inlet. See figure 18. The eliminator must be oriented correctly for proper function. There is a marked range on the pipe nipple portion of the eliminator, that must be aligned with the top of the inlet spud. A label above the jacket hole has an arrow that will point to the marked portion of the pipe nipple if the orientation is correct. If the arrow does not point within the marked range on the pipe nipple, adjust the pipe nipple to correct. A pipe union is supplied with the eliminator to reduce the probability of misaligning the eliminator accidentally while tightening the connection to the inlet water supply line. Improper orientation of the eliminator can cause poor performance of the heater and can significantly reduce outlet water temperatures during heavy draws.

The thermostat temperature dial, fig. 17, is accessible by taking off the

FIGURE18

access cover and removing the control cover. The dial is adjustable

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A.O. Smith COF-199 manual Water Temperature Control, High Limit Switch E.C.O, Burner Certificate Combustion Test