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Gas Hot Water Heater Repairs

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Gas Water Heater

Gas hot water heater need repair? If your gas water heater doesn’t heat, get hot enough, or stay lit, this expert DIY advice will help you fix gas water heater problems yourself.

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Gas water heater heating problems are typically: 1) The water heater doesn’t heat water at all; 2) It doesn’t heat enough water; or 3) Its pilot light does not stay lit. For other problems, please see Water Heater Troubleshooting & Repairs.

Gas Water Heater Doesn’t Heat

If a gas water heater fails to heat water at all, perform these diagnostics:

1Be sure the gas to the water heater is turned on. Turn the gas control knob to PILOT to prevent the burner from igniting when you are looking inside. Remove the metal cover at the bottom of the water heater and look to see if the burner and/or pilot light—the small flame at the end of the pilot gas supply tube—are lit.

2If the water heater’s pilot light has gone out, follow the instructions on the tank to relight it. It’s also possible that the gas inlet valve has been closed partially or all the way. If so, turn the handle parallel to the line and relight the pilot. If the pilot won’t light, the thermocouple may be defective—either call your gas utility company (a free service in many areas) or a water heater repair person. (Newer water heaters may have a glow plug or spark ignitor instead of a pilot—follow repair instructions in your owner’s manual.)


Heating Components of a Gas Water Heater

3If the burner is not on, replace the cover and make sure the thermostat is set to about 120 degrees F. If it isn’t, adjust it, turn on a hot water faucet, and then wait a few minutes to see if the water heater burner ignites. If it doesn’t ignite, leave the hot water running and try lowering and then raising the temperature setting on the dial until the burner ignites.

4If the burner ignites, replace the cover and turn the thermostat back to an appropriate setting. If the burner doesn’t ignite, have the water heater checked out by an appliance repair person. It could be that the heater’s thermostat is defective. Replacement is best left to an appliance repair person or a water heater specialist.

5Smell for gas. If you smell a garlic-like scent, turn the gas valve control to OFF (you may have to push down to turn it). Wait until the gas smell has dissipated before relighting the pilot light. If the gas smell is strong and doesn’t dissipate, immediately turn off the gas supply valve, ventilate the space, and call a plumber or your gas utility company from a remote location.

Water Doesn’t Get Hot Enough

When a gas water heater doesn’t provide enough hot water, do the following:

©Don Vandervort, HomeTips

Turn up the water heater dial’s setting by one increment.

1Turn the water heater’s thermostat dial to a hotter setting. If the flame ignites when you do this, leave the dial at that setting and then check the temperature of the water in about an hour. To do this, put a meat thermometer into a cup and let hot water from a faucet flow into the cup for about a minute. Then read the temperature.

2If you don’t hear the water heater’s burner ignite and/or the water just keeps getting colder, check the pilot light to be sure it hasn’t gone out. If it has, follow the manufacturer’s instructions on how to relight it and see How to Relight a Gas Water Heater. As you will see in that article, relighting a water heater usually involves turning the water heater’s gas valve to OFF and then to PILOT. You typically hold down a button, light the pilot, and wait until a status light signals that you can turn the dial from PILOT to ON.

Pilot Light Doesn’t Stay Lit

If your gas water heater’s pilot light goes out, follow the instructions on the tank to relight it or see How to Relight a Gas Water Heater, as discussed above. If the pilot light keeps going out, its orifice could be dirty and clogged, making the flame small and unsustainable. Check to make sure there is no obvious dirt and debris clogging it.

If this is not the issue, there may be a problem with the thermocouple. This is the part that extends from the temperature control into the flame of a pilot light and helps the main burner fire up once the water temperature has gone too low. The pilot light could be affected if the thermocouple is faulty or does not come into contact with the pilot flame. If you are handy, you can replace this part yourself. If not, call in a service technician.

Low gas pressure or a malfunctioning gas control valve could also cause a pilot light to go out repeatedly. Call an appliance repair person or your gas company if you suspect this is the case.

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Join the Conversation

  • Don Vandervort, HomeTips

    Do you live in a region with harsh winter temperatures? If you do, remember that the water heater is refilling with extremely cold water as you shower. If this is the case, turn the water heater’s dial to a warmer setting until the weather warms up. This will help some, but also uses more energy.

  • brandy

    My gas water heater is lit but I have no hot water

    • warren

      Check to see if water is getting to tank.

    • Don Vandervort, HomeTips

      Most of the problems and solutions are in the article above. We need more info if your situation falls outside of those answers.

  • Sarah Pursche

    We are having an issue with the pilot. We get it lit then release the button and it goes out. Any ideas what this could be?

    • Don Vandervort, HomeTips

      This usually indicates a faulty thermocouple—the little device that senses when the pilot light is lit.

  • Gary Shan

    i have a gas water heater in a rental and is used almost exclusively for the shower in Texas -yesterday after running a bath I noticed no more hot water when shaving. Its normal for the temp and flow to need recharge when running a full bath normally but water does get hot enough to be to hot. ALso notice the noise level of the heater is loud sounding like its working overdrive to reheat the tank. It has a enclosed pilot so you can see it have a good flame going. After a couple hours I cut off the pilot valve to off and then closed the gas supply valve. I go off and do my errands for the day and return sev hours later and noise level is still loud and it had been long enough for the tank to cool off from being overheated. Seems my tank was filling and draining nonstop so I shutoff the in and out lines to the tank and no more noise.

    Any ideas on what I need to do to fix this? Really dont want to force my landlord to fix this since I will probably be announcing my move out date in the next 48 hrs

  • Loracakes

    i had hot water earlier today . but came home 8 hours later …to luke warmer water.. it never gets hot.. it gas ,i dont see pilot light ? tried turning it down, while running hot water faucet for a minute..Still nothing. all I want to do take a Hot bath after a long day.. boyfriend sleeping and went to bed Grumpy, Dont want to bother him.. can someone help with maybe a idea /

  • Don Vandervort, HomeTips

    I am going to guess that the water heater’s thermostat is going bad. It could be that the water heater doesn’t kick on until the water in it is cold. Overnight the hot water turns to warm. Then you use up the warm water in the morning, and cold water replaces it…finally “flipping the switch” on the thermostat.

  • Carol T

    Thank you! Ive asked so many water heater people and this is the first answer that makes sense to me.

    • Don Vandervort, HomeTips

      There are a few other possible causes, but this is the most likely one that occurs to me. I hope replacing the thermostat fixes it! Thanks for visiting HomeTips.

  • J5a8m

    What does it mean when the water heater pilot is on but no hot water is coming out of the taps?

    • Don Vandervort, HomeTips

      It usually means the burner isn’t working. Remove the cover and look inside the water heater to see if the burner fires when you turn the temperature dial toward “hotter.” Try turning the temperature dial down then back up an couple of times. If that doesn’t do it, the thermocouple or gas control valve may need adjustment or replacement by a pro.

  • Don Vandervort, HomeTips

    If the burner is working properly, it should take a few hours, depending upon its size. No, running your hot water will only make it take longer—and waste water.

  • joy torrente

    Hello! my water heater’s motor would stop after few minutes of turning back on. now i a see the light on the control flashes a certain pattern (2flashes-pause-3flashes) which indicate in the status sticker as “FVD interface failuer/miswiring”. How to fix this problem? Thanks!

  • Michele Collins Tater

    I have a brand new hot water tank that has a lit pilot but the burner will not light. Could it be a gas issue, since I am using a flex tube instead of a metal pipe that I use on the old hot water tank.

  • Don Vandervort, HomeTips

    I recommend you just turn it off, then relight it.

  • Dave

    My gas water heaters pilot light is lit and the burner ignits when I turn the temp up but the water isn’t getting that hot and doesnt stay hot. What could be the issue?

  • mark

    i have a gas hot water heater…lately it will run ..heat the water ..and then suddenly stop running …there is a black toggle switch near base of unit ..which i switch off for 5 seconds or so ..then switch back on ..which at that point the blower will start and the burners will turn on and start to heat ..however this appears to be getting alot worse ..where more frequently iam turning the switch on and off this definitely a thermostat issue or is there something else iam not considering ?…pls advise

  • Sarah Rhodes

    hot water heater was making noise like cold water was going into tank. I found that strange because no hot water had been used for awhile. I check it after 10 min and found water was still running. Then there was water was leaking out of the bottom. turned the water off and running water sound stopped and so did the leaking. Is there a valve that stops the cold water from going into the water heater when it is full?

    • Jettdirect

      Your water heater is leaking out the bottom from mineral damage. It is time to replace it.

  • Tom Wilt

    Water pressure is very low? Cold OK. Hot low pressure. What causes that?

  • Teresa

    I have hot water but no hot water pressure. The cold is fine. Any help on what the problem could be?

    • Carl Dunkin

      try opening and closing the shutoff valves under your sinks or it could be in the faucet itself hard water causes a chemical buildup in pipes etc.

  • Gustavo Lopez

    I replaced the thermocouple and the pilot light tube. Everything lights up i just have what seems to be a leak cause i have an extra flame coming out. I tighten things again and same results

  • John R Satawake

    Replaced the thermocoupler, lit the pilot, the burner came on then when out after a few seconds. Relit several times and kept going out.

  • Chris Willis

    Checked my pilot light and it is lit, I turned the thermostat down and turned on hot water running in kitchen sink and watched hot water heater for a few min. and heater ignited to heat water. It doesn’t happen all the time but its getting more regular that my wife gets home from work and goes to run a hot bath and get about 1-1/2″ of hot water in tub before water turns cold. I can hear hot water heater working to heat water. What could be my problem?

  • Janice Grahovac

    Hi. I hope someone can help me. I have a has water heater amd it seems to only work when it wants to. Regardless of amount of use some days I have got water and some days it runs out of hot water immediately even if it hasn’t been used all day. And some days it runs out half way through a shower. I have already turned the temperature almost all the way up and nothing is helping. Is there a way too fix this or is it time for a replacement?


      I know this sounds stupid, but may be the hot and cold service lines to the heater are installed backward, or the drop tube in the heater needs to be replaced.

      • Janice Grahovac

        I will be checking those. Thank you

    • Don Vandervort, HomeTips

      Is this water heater gas or electric?

      • Janice Grahovac

        It is gas

  • shadow1458

    Replaced the thermocoupler, lit the pilot, the burner came on then went
    out after a few seconds. Relit several times and kept going out, does anyone know what causes this? It’s driving me crazy

    • Donald Sanders

      Did you ever get a reply? My water heater is doing the same as yours did.
      Thank you

  • WMR

    Woke up with cold water. I lit the pilot light and it stayed on for a couple of seconds then it went out. I relit the pilot light and it stayed on after the fan started running. Then I get the hot water. Later the pilot light will go out again. Have Bradford White Co TTW2 model MIITW75S5CX8 Thanks!

  • Michelle Menz-Feltz

    i just replaced my thermocouple as my gas water heater would not keep the pilot lit anymore and heat up the water… well here is the strange part, after replacing the thermocouple putting everything back together, lit the pilot, turned the regulator up to where we always had it the burner kicked on and heated up the water. Now i am noticing that the pilot seems to have a very large flame and our water is scalding hot. turned down the temperture and still the water is scalding hot, ran the hot water to see if it would run out of hot water and it does not, but the burner never comes on and the pilot is always lit (which i know is supposed to happen) but i cannot get the water temp to turn down now…. what is wrong now with my water heater that i have continuous scalding hot water, a new thermocouple, a lit pilot, a burner that does not come on anymore to heat up the water as the water is always scalding????????

  • Michelle Menz-Feltz

    so put new thermocoupler on two nights ago… lit the pilot and the burner kicked on cause i had cold water instead of hot… now my problem is that the burner has not kicked back on, the flame on the pilot is very big and i have scalding hot water that wont seem to cool down anymore… i have turned the dial to the low setting to see if it would get colder and it has not… What do i do now?

  • Nancy

    Every tap has great hot water but my shower is not the same, when no one runs anything ud think tht there should be hot water but not here my shower seems never to have any or enough hot water

  • Shane Veltri

    Did either of you figure out what the problem was? Mine is doing the same. thanks

    • Biker45

      Call the 1 800 number on the side of the water heater as I did. Mine is a safety that is under the burner that went out. Company is sending me one for free. It will be here tomorrow. That is the best advice I can give. I had already replaced the thermocouple before doing this.

  • CB2017

    My public utilities replaced my meter and now my hot water doesnt work. Everyone is telling me one has nothing to do with the other but how can that be, it happened right after they did it? Who should I call, the gas company to check the pilot (my heat in my house works fine) or the water company…

    • Don Vandervort, HomeTips

      Which meter was replaced? If it was the gas meter, you have to make sure they turned the main gas valve back on. Whenever the gas gets shut off, any appliances that have a pilot light need to have the pilot re-lit.

  • Deborah Moore

    I have a gas water heater with electric ignite. Works fine all spring, summer and fall. However, winter gets here and it won’t light half the time. You have to reset it. Why would it do this in just in cold weather?

  • jim b

    my pilot light is lit but the burner doesn’t come on.

  • h Johnson

    I have a 50 gal gas Rheem hot water heater. 3 years old. The water is hot sometimes and sometimes not. Last night started bath water and it was cool after the water heater was not used since morning. Drained the tub and the water heater was on. Waited about 1 hour and had plenty of hot water for the bath. This has been going on for a while. Shower this morning was fine. So tried to drain and flush the unit but not much water came out. Had the pressure release valve open and then opened the closes hot water outline in a bath. Still no draining. But some water was coming out of the pressure release drain pipe outside. Thought the drain might be stopped up but could not get a stiff wire up into the tank. Everything is hooked up correctly. So I tried to open cold water inlet and stir up the water in the tank to maybe free up the drain. Didn’t help any. At a loss as to what to do. Should I disconnect the cold water inlet and leave the pressure release valve closed to see it that will drain the tank. Don’t know what to do now to drain and flush the tank if that is the problem. It is a problem any to not be able to drain the tank but is this what is causing my problem with running out of hot water sometimes?

  • h Johnson

    Just say the tips of how to unclog the drain pipe by either stepping on the hose a few times or back flush the drain with the hose. Will try that tomorrow.

  • Alexzandra Lovely Campbell


  • D C

    Sounds like the thermocouple, it’s a little probe that sticks into the flame that says things are burning so it’s OK for the gas to stay open.It does this by generating a very low voltage/resistance change when exposed to heat, that way if there is no flame the gas would turn off so you don’t fill your area with un-burned gas.
    Usually they are pretty easy to remove,it will only have one wire, clean it if it looks corroded at the part that would be in the flame with a light rubbing of fine steel wool or similar, don’t sand it down, just a light wiping. Or better yet buy a new one, they are only 15-20 bucks. After 8 years I would not be surprised to see one fail. youtube will have videos

  • Jan Skinner

    new water tank installed, pilot light comes on, burner comes on. Water cold when faucet first turned on, them water gets hot for a few minutes, then goes cold again.

  • Michelle Matthews

    My gas hot water heater provides us with hot water and then when it feels like it we get hot water again. When we are out of hot water it will last a few days than comes on all by itself again. Any ideas as to what is causing this?

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