How to Repair a Gas Water Heater

  • 01 of 07

    How to Repair a Gas Water Heater

    Gas Water Heater
    Gas Water Heater. © Home-Cost.com 2006

    Unlike tank-less water heaters, standard tank-type water heaters use an insulated storage tank. The construction or anatomy of this appliance is explained in the tutorial Anatomy of the Gas Water Heater.



    Water heaters are generally very reliable but occasionally they do have problems.


    These problems can include:


    • No hot water
    • Inadequate hot water
    • Rust colored water
    • Rotten egg odor
    • Low rumbling or popping noise
    • Higher pitched whining
    • Water leaking around base of heater


    Before any troubleshooting is done,...MORE make sure to prepare safely for the job by doing the following:


    • Turn off power to an electric water heater. Do this by turning off the circuit breaker or fuse powering the heater.
    • Turn the gas pilot control valve to "pilot" setting.
    • Shut off the water supply to the water heater.

    Let's take a look at each problem and what possible causes and repairs exist.


    Continue to 2 of 7 below.
  • 02 of 07

    PROBLEM: No Hot Water is Produced

    Earth Day Challenge
    Robert D. Barnes / Getty Images

    No Hot Water is Produced:


    Possible Causes


    • Faulty gas pilot
    • Faulty gas thermocouple
    • Faulty gas pilot control valve

     


    Possible Repairs


    • Check gas pilot flame and pilot operation. See How to Light a Gas Furnace Pilot for similar operation.
    • Re-tighten, reposition or replace the gas thermocouple.
    • Replace the gas pilot control valve.

    Continue to 3 of 7 below.
  • 03 of 07

    PROBLEM: Inadequate Hot Water

    Male Finger Turning Up Tankless Water Heater Temperature
    BanksPhotos / Getty Images

    Inadequate Hot Water:


    Possible Causes


    • Unit is undersized for water heating demands
    • Broken or damaged dip tube allowing cold and hot water to mix in tank
    • Faulty plumbing installation has crossed cold and hot water connections
    • Gas supply or control problems

     


    Possible Repairs


    • Make sure water heater is not being overtaxed by hot water supply demands. The water heater should have 75% of its capacity as hot water (e.g., a 40 gallon WH should be used for a demand of 30 gallons). To determine required capacity...MORE see Calculating Fixture Flow Rates.
    • Undo cold water inlet and pipe nipple and remove dip tube. Check condition and replace if required.
    • Check for crossed connection by turning off water supply to water heater. Open a hot water faucet. If there is water flow, then their is a crossed connection somewhere. Check for a hot water line connected to a cold water connection on the water heater or appliances such as washer, dishwasher, faucet or shower valves.
    • Check for proper flame from burner. A natural gas flame should be a bright blue with the tip of the flame having just a tinge of yellow. A propane flame should have a bluish green flame with a tinge of yellow at the tip.

    Continue to 4 of 7 below.
  • 04 of 07

    PROBLEM: Rust Colored Water

    Sacrificial Anode Rod for Water Heater
    Sacrificial Anode Rod for Water Heater.

    Rust Colored Water:


    Possible Causes


    • Corrosion occurring inside glass lined tank
    • Sacrificial anode rod is failing (anode rods dissolve slowly to prevent rusting in the tank)

     


    Possible Repairs


    • Replace sacrificial anode rod with magnesium anode rod. Anode rods are available from a plumbing supply house.

    Continue to 5 of 7 below.
  • 05 of 07

    PROBLEM: Rotten Egg Smell

    High Angle View Of Broken Egg Shells In Crate
    Silvia Elena Castañeda Puchetta / EyeEm / Getty Images

    Rotten Egg Smell:


    Possible Causes


    • Bacteria in the tank sediment fed from hydrogen gas created from decay of sacrificial anode.

     


    Possible Repairs


    • Flush water heater
    • Using a hydrogen peroxide solution of 2 pints 3% peroxide to 40 gallons of water, treat tank and run some of the solution into water lines.
    • Let peroxide solution set in tank and pipes for 2 hours. Solution is not toxic and requires no rinsing.
    • If problem persists, replace anode with a zinc-alloy anode.
    • If problem still remains, replace water...MORE heater with a plastic lined tank type.

    Continue to 6 of 7 below.
  • 06 of 07

    PROBLEM: Low Rumbling or Popping Noise

    Son watching father check hot water tank with energy application on digital tablet
    Monty Rakusen / Getty Images

    Low Rumbling or Popping Noise:


    Possible Causes


    • Noise heard is sound of boiling water. Excessive buildup of sediment in bottom of tank is causing overheating of tank bottom and boiling of water to occur.

     


    Possible Repairs



    Continue to 7 of 7 below.
  • 07 of 07

    PROBLEM: Water Leak Around Base of Heater

    Close-up of drain pipe leaking water
    DIGIcal / Getty Images

    Water Leak Around Base of Heater:


    Possible Causes



     


    Possible Repairs


    • Place bucket under overflow pipe. Open and flush T&P valve clear of debris. If leak remains from valve, replace valve.
    • Reduce thermostat setting to prevent tank overheating and opening T&P relief valve.
    • Inspect bottom of tank by...MORE looking through combustion chamber. If water marks or heavy rusting is noticed or if water is noticed setting in combustion chamber bottom, then the water heater needs to be replaced.