A.O. Smith FMD 40, FMD 50 Anode ROD Inspection, Draining, Water system. Check for any leaks

ANODE ROD INSPECTION TEMPERATURE-PRESSURE RELIEF VALVE OPERATION

Each water heater contains at least one anode rod, which will slowly deplete (due to electrolysis) prolonging the life of the water heater by protecting the glass-lined tank from corrosion. Adverse water quality, hotter water temperatures, high hot water usage, and water softening methods can increase the rate of anode rod deple- tion. Once the anode rod is depleted, the tank will start to corrode, eventually developing a leak.

Certain water conditions will cause a reaction between the anode rod and the water. The most common complaint associated with the anode rod is a “rotten egg smell” produced from the presence of hydrogen sulfide gas dissolved in the water. IMPORTANT: Do not remove this rod permanently as it will void any warranties. The parts list includes a special anode rod that can be ordered if water odor or discoloration occurs. NOTE: This rod may reduce but not eliminate water odor problems. The water supply system may require special filtration equipment from a water conditioning company to successfully eliminate all water odor problems.

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 removed from the water heater tank every 3 years for inspection. 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.

If the anode rod show signs of either or both it should be replaced. NOTE: Whether re-installing or replacing the anode rod, check for any leaks and immediately correct if

found.	EXPOSED
	SUPPORT
In replacing the anode:	WIRE

1. Turn off gas supply to the water heater.

2. Shut off the water supply and open a nearby hot water faucet to depressurize

the water tank.PITTED

3. Drain approximately 5 gallons of water ANODE from tank (Refer to “Draining” for proper ROD procedures). Close drain valve.

4. Remove old anode rod.

5. Use Teflon® tape or approved pipe sealant on threads and install new anode rod.

6. Turn on water supply and open nearby
hot water faucet to purge air from	EXPOSED
water system. Check for any leaks and	SUPPORT
immediately correct any if found.	WIRE

The temperature-pressure relief valve must be manually operated at least once a year.

When checking the temperature-pressure relief valve operation, make sure that (1) no one is in front of or around the outlet of the temperature- pressure relief valve discharge line, and (2) that the water discharge will not cause any property damage, as the water may be extremely hot, see Figure 39.

FIGURE 39.

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, follow the draining instructions, and replace the temperature-pressure relief valve with a new one.

If the temperature-pressure relief valve on the appliance weeps or discharges periodically, this may be due to thermal expansion. You may have a check valve installed in the water line or a water meter with a check valve. Consult your local water supplier or service agency for further information. Do not plug the temperature-pressure relief valve.

DRAINING

The water heater should be drained if being shut down during freezing temperatures. Also periodic draining and cleaning of sediment from

Restart the water heater as directed under

FIGURE 38

the tank may be necessary.

“Operating Your Water weater.” See the Repair Parts Illustration for anode rod location.

1.Turn the gas control knob to the “OFF” position.

2.OPEN nearby hot water faucets and leave open until the water is no longer hot.

3.CLOSE the cold water inlet valve to the water heater.

4.Connect a hose to the drain valve and terminate to an adequate drain or outdoors.

5.OPEN the water heater drain valve to allow for tank draining. NOTE: If the water heater is going to be shut down and drained for an extended period, the drain valve should be left open with hose connected allowing water to terminate to an adequate drain.

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