AO Smith
Electric Water Heater

Model #ECT40 AO Smith water heater

Here are the diagrams and repair parts for AO Smith ECT40 water heater, as well as links to manuals and error code tables, if available.

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Save to my profileError Codes

    Showing 10 of 23 parts

    Insulation

    #17

    Water heater Diagram

    Insulation

    Part #9003716005
    ?
    Manufacturer substitution
    This part replaces 183256-000. Substitute parts can look different from the original.
    This part replaces 183256-000
    $23.49

    In Stock

    Box Cover

    #20

    Water heater Diagram

    Box cover

    Part #184660-000
    ?
    Manufacturer substitution
    This part replaces 184660-000. Substitute parts can look different from the original.
    This part replaces 184660-000
    $17.99

    In Stock

    Water Heater Access Panel

    #1

    Water heater Diagram

    Water heater access panel

    Part #9003900005
    ?
    Manufacturer substitution
    This part replaces 181260-000. Substitute parts can look different from the original.
    This part replaces 181260-000
    $20.99

    In Stock

    Water Heater Heating Element

    #6

    Water heater Diagram

    Water heater heating element

    Part #9000095015
    ?
    Manufacturer substitution
    This part replaces 042286-022. Substitute parts can look different from the original.
    This part replaces 042286-022
    $28.99

    In Stock

    Insulation

    #18

    Water heater Diagram

    Insulation

    Part #9003971005
    ?
    Manufacturer substitution
    This part replaces 181639-003. Substitute parts can look different from the original.
    This part replaces 181639-003
    $21.99

    In Stock

    Terminal Cover

    #15

    Water heater Diagram

    Terminal cover

    Part #9006078015
    ?
    Manufacturer substitution
    This part replaces 182117-001. Substitute parts can look different from the original.
    This part replaces 182117-001
    $37.62

    In Stock

    Water Heater Anode Rod

    #9

    Water heater Diagram

    Water heater anode rod

    Part #9003944005
    ?
    Manufacturer substitution
    This part replaces 183523-029. Substitute parts can look different from the original.
    This part replaces 183523-029
    $32.99

    In Stock

    Water Heater Heating Element

    #14

    Water heater Diagram

    Water heater heating element

    Part #9000092015
    ?
    Manufacturer substitution
    This part replaces 042286-021. Substitute parts can look different from the original.
    This part replaces 042286-021
    $21.99

    In Stock

    Dip Tube

    #2

    Water heater Diagram

    Dip tube

    Part #9001596005
    ?
    Manufacturer substitution
    This part replaces 183900-052. Substitute parts can look different from the original.
    This part replaces 183900-052
    $22.61

    In Stock

    Water Heater Thermostat

    #13

    Water heater Diagram

    Water heater thermostat

    Part #9004428115
    ?
    Manufacturer substitution
    This part replaces 182354-000. Substitute parts can look different from the original.
    This part replaces 182354-000
    $46.99

    In Stock

    Symptoms common to all water heaters

    Choose a symptom to see related water heater repairs.

    Main causes: water supply needs chlorine treatment, anode rod too reactive
    Main causes: thermostat temperature set too high, thermostats need adjustment, faulty thermostat, shorted heating element
    Main causes: thermostats need adjustment, water heater capacity too low, bad heating element, thermostat failure, excessive tank sediment
    Main causes: lack of power, no gas supply, thermostat limit switch tripped, bad element, bad thermostat, gas valve failure, bad thermocouple
    Main causes: faulty pressure relief valve, water is overheating
    Main causes: broken heating element, thermostat failure, excessive tank sediment, tank size too small, burner valve assembly failure
    Main causes: loose water pipe fittings, leaky drain valve, bad temperature-pressure relief valve, leaky heating element, cracked tank

    Repair guides for electric water heaters

    How to replace an electric water heater anode rod

    If your hot water begins to smell like rotten eggs, replace the anode rod with a zinc-aluminum anode rod following the instructions in this repair guide.

    Repair difficulty
    Time required
     15 minutes or less
    How to replace an electric water heater thermostat

    If the water temperature fluctuates or you don't get enough hot water, follow these instructions to replace your water heater's thermostat.

    Repair difficulty
    Time required
     30 minutes or less
    July 1, 2015
    By Lyle Weischwill
    How to replace a water heater drain valve

    If the drain valve on your electric water heater is leaking water, replace it following these step-by-step instructions.

    Repair difficulty
    Time required
     30 minutes or less

    Articles and videos common to all water heaters

    Use the advice and tips in these articles and videos to get the most out of your water heater.

    September 26, 2019

    Keeping your smart appliances secure from hackers

    By Lyle Weischwill

    Find out how to protect your smart appliances from malevolent invasions by hackers.

    November 1, 2018

    How to read a wiring schematic video

    By Sears PartsDirect staff

    Learn how to decipher symbols so you can buy the right part for your problem.

    August 1, 2015

    Water heater common questions

    By Sears PartsDirect staff

    These common questions and answers can help you make the most of your water heater.