AO Smith Commercial Heat Pump Water Heaters CAHP-120

Warning: Ensure no one is in front of or around the outlet of the Temperature-Pressure Relief Valve discharge line during the test

Warning: Use care when operating valve as the valve may be hot

Did the valve seat properly and operate freely when the lever was lifted?

Did the valve fail to completely reset and continue to release water after manual operation?

If yes, 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

Does the Temperature-Pressure Relief Valve on the water heater weep or discharge periodically?

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.” The Temperature-Pressure Relief Valve is not intended for the constant relief of thermal expansion

Temperature-Pressure Relief Valve leakage due to pressure build up in a closed system that does not have a thermal expansion tank installed is not covered under the limited warranty. Thermal expansion tanks must be installed on all closed water systems

Warning: Do not plug the Temperature-Pressure Relief Valve opening. This can cause property damage, serious injury or death

Turn off electrical supply to the water heater

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

Drain approximately 5 gallons of water from tank

Remove the plastic cap on top of the water heater tank

Remove the anode by loosening the 3/4\ NPT bushing that forms the top of the anode"

Remove the entire anode rod from the water heater for inspection

Clean the anode rod with a soft cloth and reinstall if undamaged

Replace the anode rod if damaged

Warning: This procedure requires trained personnel with PPE!

Presence of sediment layer at the bottom of the tank

Presence of lime scale on heating elements

Characteristics of water supply

Noises during operation due to lime scale

Heating element removed for examination

All elements removed and cleaned if one is scaled

Turn off the electrical supply to the water heater

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 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

Important: Replacement heating elements must be of the same style and Voltage/wattage rating as the ones originally in the water heater.

This information can be found on the flange or terminal block of the element or on the water heater data plate.

DO NOT replace the elements) with a wattage, style or shape different than the elements specified for the upper and/ or lower element.

Power to the water heater turned off at the breaker disconnect switch?

Verified there is no power at the incoming power connection to the water heater with an AC volt meter?

Hot water faucet opened and run until the water is no longer hot?

Cold water shut-off valve to the heater closed?

Water heater drained by connecting a hose to the drain valve and terminating it to an adequate drain or to the exterior of the building?

Water heater’s left side access panel and the element access cover removed?