What parts fit the AO Smith ECT66?

Anode rod 100109594, Element 100108290, Thermostat 100109846, Element 100108283, Thermostat 100110039.

AO Smith ECT66 water heater parts: anode rod

Anode rod

Replaces 183523-033

Protects the tank from rust. Makers suggest checking it every few years.

Shop the anode rod on Amazon Other models that use 100109594

Element

Replaces 042285-025

An electric water heater with no hot water usually has a burned-out element.

Shop the element on Amazon Other models that use 100108290

Thermostat

Replaces 182354-000

Reads or limits temperature. A failed one can stop the heat or let it run too hot.

Shop the thermostat on Amazon Other models that use 100109846

Element

Replaces 042286-021

An electric water heater with no hot water usually has a burned-out element.

Shop the element on Amazon Other models that use 100108283

Thermostat

Replaces 182359-000

Reads or limits temperature. A failed one can stop the heat or let it run too hot.

Shop the thermostat on Amazon Other models that use 100110039

1Anode rod100109594

2Element100108290

3Thermostat100109846

Part numbers come from the Sears PartsDirect parts list for the AO Smith ECT66 (view the list), checked November 15, 2026. Amazon buttons open a search for the part number; we may earn a commission.

Where the model number is

On the large label on the side of the tank, near the gas valve or the upper access cover.

Other AO Smith water heaters

ECRT52ECS30ECS50ECT120ECT52ECT55EJCS20EJCT20ELJC15ELJC20