AO Smith Commercial Electric Tank Water Heaters DRE-120A

Warning: This procedure requires trained personnel with PPE!

Turn off electrical disconnect switch

Remove the elements and gaskets from the openings

Brush loose scale from elements

Place limed ends of heating elements into UN•LIME delimer and allow scale to dissolve

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

IMPORTANT: Do not remove this rod permanently as it will void any warranties. A special anode rod may be available 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.

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.

Is the majority of the rods diameter less than 3/8?

Are significant sections of the support wire (approx. 1/3 or more of the anode rod's length) visible?

NOTE: Whether re-installing or replacing the anode rod, check for any leaks and immediately correct if found.

Turn off electric supply to the water heater.

Turn off the electrical supply to the water heater at the breaker or disconnect switch.

Ensure the cold water inlet valve is open.

Open a nearby hot water faucet and let the water run until the water is no longer hot. Then close the hot water faucet.

Connect a hose to the water heater drain valve and terminate it to an adequate drain.

Ensure the drain hose is secured before and during the entire flushing procedure. Flushing is performed with system water pressure applied to the water heater.

Open the water heater drain valve to flush the storage tank.

Flush the water heater storage tank to remove sediment and allow the water to flow until it runs clean.

Close the water heater drain valve when flushing is completed.

DANGER! Burn hazard. Hot water discharge. Keep hands clear of drain valve discharge.

Turn off the electrical supply to the water heater at the breaker or disconnect switch.

Ensure the cold water inlet valve is open.

Open a nearby hot water faucet and let the water run until the water is no longer hot.

Close the cold water inlet valve to the water heater.

Connect a hose to the water heater drain valve and terminate it to an adequate drain.

Open the water heater drain valve and allow all the water to drain from the storage tank.

Close the water heater drain valve when all water in the storage tank has drained.

Close the hot water faucet opened in Step 3.

Warning: Ensure no one is in front of or around the outlet of the temperature-pressure relief valve discharge line

Warning: The water manually discharged may be extremely hot and can cause bodily injury or property damage

Temperature-pressure relief valve manually operated

Did the valve completely reset and stop releasing water after manual operation?

If the valve did not reset and continues to release water, close the cold water inlet to the water heater and follow the draining instructions

Cold water inlet to the water heater closed

Replace the temperature-pressure relief valve with a properly rated/sized new one if it continues to release water

Upload a photo of the new temperature-pressure relief valve