A.O. Smith XDVS, GDVS, GDVH Pilot and Main Burner, Temperature & Pressure Relief Valve, Draining

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 dial, Figure 99, 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. The water temperature adjusting dial was factory set at the lowest temperature; all the way clockwise to the mechanical stop. Turning the dial counterclockwise increases temperature and clockwise reduces temperature.

SETTING THE WATER HEATER TEMPERATURE AT 120°F (APPROX. “” MARK ON FACE OF THERMOSTAT) WILL REDUCE THE RISK OF SCALDS. Some states require settings at specific lower temperatures.

Figure 99 shows the approximate water temperatures produced at various thermostat dial settings. 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 30°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
VERY HOT= approx. 160°F	About 1/2 second
C = approx. 150°F	About 1-1/2 seconds
B = approx. 140°F	Less than 5 seconds
A = approx. 130°F	About 30 seconds
= approx. 120°F	More than 5 minutes
LOW = approx. 80°F

FIGURE 99

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

SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF, TURN OFF THE MAIN MANUAL GAS CONTROL

VALVE TO THE APPLIANCE (SEE FIGURE 1).

MAINTENANCE

FOR YOUR SAFETY AND SATISFACTORY OPERATION, IT IS RECOMMENDED THAT THIS HEATER BE CHECKED ONCE A YEAR BY A COMPETENT SERVICE PERSON.

USERS OF THIS APPLIANCE SHOULD BE AWARE THAT GAS COMPONENTS WEAR OUT OVER A PERIOD OF TIME. THE

GAS CARRYING COMPONENTS OF THIS APPLIANCE SHOULD BE INSPECTED FOR PROPER OPERATION PERIODICALLY BY A QUALIFIED SERVICE TECHNICIAN.

PILOT AND MAIN BURNER

Check pilot and main burner every six months for proper flame characteristics. This is done by removing door on heater, fig. 1. The main burner should provide complete combustion of gas; ignite rapidly; give reasonably quiet operation; cause no excessive flame lifting from burner ports. Make sure that the flow of combustion and ventilation air is not blocked.

If proper flame characteristics are not evident, check for accumulation of lint or other foreign material that restricts or blocks the air openings in the heater or burner.

WARNING

SOOT BUILD-UP INDICATES A PROBLEM THAT REQUIRES CORRECTION BEFORE FURTHER USE. CONSULT WITH A QUALIFIED SERVICE TECHNICIAN.

Should the main burner or burner air openings require cleaning, turn the gas control knob to “OFF” position and allow the burner to cool. Remove the burner and clean with a soft brush. Clean main burner orifice with a suitable soft material.

HIGH TEMPERATURE LIMIT SWITCH (Single-Use Type Energy Cut Off)

The thermostat has a built-in limit switch which will extinguish the pilot light in case of excessive water temperatures. The pilot cannot be relit until the entire thermostat (labeled as single-use type) is replaced. It is important that a serviceman be called to determine the reason for limit operation and thus avoid repeated thermostat replacement. Lower the temperature adjustment dial setting on the new control.

VENTING

HAVE VENTING SYSTEM CHECKED EVERY SIX MONTHS FOR OBSTRUCTIONS AND/OR DETERIORATION IN VENT PIPING.

TEMPERATURE & PRESSURE RELIEF VALVE

At least once a year, the temperature and pressure relief valve, fig. 1. must be checked to ensure that it is in operating condition. Lift the lever at the top of the valve several times until the valve seats properly and operates freely.

If water does not flow, remove the valve and inspect for obstructions or corrosion. Have a qualified servicer replace with a new valve of the recommended size as necessary. Do not attempt to repair the valve, as this could result in improper operation and a tank explosion. In areas with poor water conditions, it may be necessary to inspect the T&P valve more frequently.

WARNING

THE WATER PASSING OUT OF THE VALVE DURING THIS CHECKING OPERATION MAY BE EXTREMELY HOT. AVOID CONTACT AND DISCHARGE SAFELY TO PREVENT WATER DAMAGE.

DRAINING

If the heater is to be shut off and exposed to freezing temperatures, it must be drained. Water, if left in the tank and allowed to freeze, will damage the heater.

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