A.O. Smith Commercial Gas Tank Water Heaters BL-80

Flush the heater by opening the drain valve and allowing two gallons of water to drain. Keep the inlet water valve open to maintain pressure in the tank.

Shut off the gas and drain the heater before opening the cleanout.

Remove the outer cover plate from the lower side of the heater jacket.

Remove the six hex head screws securing the tank cleanout plate and remove the plate.

Remove lime, scale, or sediment, taking care not to damage the glass lining.

Inspect the cleanout plate gasket. If a new gasket is required, refer to the replacement parts list for the item number.

Install the cleanout plate. Ensure the plate is drawn up tight by securely tightening the screws.

Replace the outer jacket cover plate.

CAUTION! Property Damage Hazard. Avoid water heater damage. Inspection and replacement of anode rod required.

The anode rod is used to protect the tank from corrosion. Most hot water tanks are equipped with an anode rod. The submerged rod sacrifices itself to protect the tank.

Anode deterioration depends on water conductivity, not necessarily water condition. A corroded or pitted anode rod indicates high water conductivity and should be checked and/or replaced more often than an anode rod that appears to be intact.

Artificially softened water is exceedingly corrosive because the process substitutes sodium ions for magnesium and calcium ions. The use of a water softener may decrease the life of the water heater tank.

The anode rod should be inspected after a maximum of three years and annually thereafter until the condition of the anode rod dictates its replacement.

NOTE: Artificially softened water requires the anode rod to be inspected annually.

The following are typical (but not all) signs of a depleted anode rod: The majority of the rods diameter is less than 3/8. Significant sections of the support wire (approx. 1/3 or more of the anode rod's length) are visible.

Enter the diameter of the anode rod

Warning: Flood damage to a water heater may not be readily visible or immediately detectable. However, over a period of time a flooded water heater will create dangerous conditions which can cause DEATH, SERIOUS BODILY INJURY, OR PROPERTY DAMAGE.

Contact a qualified installer or service technician to replace a flooded water heater. Do not attempt to repair the unit! It must be replaced!

Visual inspection of the main burner and pilot burner

Inspect burner flames through viewport. Flames should be very small with a blue haze and small amounts of yellow or orange at the edges. After several minutes of operation the burner screen may glow red.

Check for sooting. Soot is not normal and will impair proper combustion.

Soot build-up indicates a problem that requires correction before further use. Turn 'OFF' gas to water heater and leave off until repairs are made, because failure to correct the cause of the sooting can result in a fire causing death, serious injury, or property damage.

If inspection of the burner shows that cleaning is required, turn the gas control knob clockwise ( ) to the “OFF” position, depressing slightly.

NOTE: The knob cannot be turned from “PILOT” to “OFF” unless knob is depressed slightly. DO NOT FORCE.

WARNING! Carbon Monoxide and Fire Hazard

Flue gases may escape if vent pipe is not connected.

Be alert for obstructed, sooted or deteriorated vent system to avoid serious injury or death.

Do not store corrosive chemicals in vicinity of water heater.

Chemical corrosion of flue and vent system can cause serious injury or death.

Contact a qualified installer or service agency.

Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.

Visual inspection of the venting system done

Obstructions which could cause improper venting found

DANGER: Burn hazard. Hot water discharge. Keep clear of Temperature-Pressure Relief Valve discharge outlet.

It is recommended that the Temperature-Pressure Relief Valve should be checked to ensure that it is in operating condition every 6 months.

When checking the Temperature-Pressure Relief Valve operation, make sure that no one is in front of or around the outlet of the Temperature-Pressure Relief Valve discharge line, and that the water discharge will not cause any property damage, as water may be extremely hot.

Use care when operating valve as the valve may be hot.

To check the temperature-pressure relief valve, lift the lever at the end of the valve several times. The valve should seat properly and operate freely.

If after manually operating the valve, it fails to completely reset and continues to release water, immediately close the cold water inlet to the water heater and drain the water heater.

Replace the Temperature- Pressure Relief Valve with a properly rated/sized new one.

If the Temperature-Pressure Relief Valve on the water heater weeps or discharges periodically, this may be due to thermal expansion.

NOTE: Excessive water pressure is the most common cause of Temperature-Pressure Relief Valve leakage. Excessive water system pressure is most often caused by “thermal expansion” in a “closed system.”