Gas Water Heater Not Working? 10 Common Problems and Fixes Posted on February 28, 2023 Gas water heaters are an integral part of daily life. They make showers more bearable during cold mornings, and are essential for household tasks like laundry and dishwashing. When the gas water heater breaks down, it can affect the whole household, especially if it’s connected to storage tanks. In this gas water heater repair guide, we discuss what to do when your gas water heater is not working, and when to call a professional. Parts of a Gas Water Heater As the name suggests, a gas water heater uses natural gas or propane to heat up the water. It commonly has: A gas pipe for supplying gas A pilot light Burner, usually at the bottom of the hot water tank A flue to vent the exhaust fumes Each of these parts are critical to its operation. When one part suffers a malfunction, that’s when the gas water heater stops working. 10 Common Scenarios of Gas Water Heater Not Working 1. No hot water throughout the house If the water coming out of the tap or shower is cold, it could be due to one several possible issues: ☑ Thermostat See if the thermostat is not properly adjusted to the correct temperature before checking anything else. ☑ Pilot light Check if the pilot light is on, and try relighting it (see #6 below). If it still won’t work, then this is a job for the professionals. ☑ Dirty water tank Impurities in the water supply cause sediment to build up over time. These deposits can settle at the base of the tank, insulating the water from the heating element. Flush the water tank and make sure there is no mineral buildup at the bottom. ☑ Gas supply issue Check to ensure the gas valve is open and that there is a constant supply of gas. ☑ Defective gas supply valve If there are no supply issues, the gas control valve might be faulty and need replacing. This component is critical for controlling the gas flow, and requires professional service if found to be defective. 2. Water that comes out is lukewarm ☑ Clogged tank As noted above, an unflushed tank can have a layer of sediment blocking the water from the heat source. Flush and clean the tank to ensure proper heating. ☑ Damaged dip tube The water heater dip tube supplies cold water to the tank bottom where it can be heated. A damaged or broken tube releases the flow back to the top where it mixes with the hot water, reducing the overall temperature of the supplied water. 3. No hot water in a specific part of the house There may be times when only a specific tap or room doesn’t receive hot water. This indicates a problem not with the water heater but with the water supply. ☑ Closed valve First make sure the hot water valve is open all the way, since it may have been dislodged from its open setting or turned off. ☑ Cross connection issue A cross connection is when a damaged mixing valve allows cold water to pass on to the hot side. This means cold water is getting into the hot water pipe. Replace the shower or mixing valve. ☑ Pipe deposits The water pipes may have a mineral buildup that restricts the water flow to the hot water pipe. This commonly occurs at elbow joints or old steel pipes. ☑ Ice buildup Frozen pipes can block water flow to certain areas of the house, especially those exposed colder temperatures. See our guide: The 6 Signs of a Frozen Pipe, and How to Fix Them. ☑ Check valve issue This applies to water recirculation pumps. A broken check valve could be mixing cold water into the hot water pipe. 4. Dirty or discolored water Murky or rust colored water is more than just a headache, it can be a health hazard. ☑ Cloudy water Water that is murky but not rust-colored or red indicates a mineral buildup. Calcium and magnesium are the typical culprits. This can be resolved by flushing the tank. If the issue happens frequently, it may be due to the water supply of your area. In this case, it may be worth investing in a water softener. ☑ Rusty water This indicates corrosion problems in the following areas: If it happens throughout the whole house: Anode rod Water tank If it happens only to a specific part of the house: Water pipes If rust is visible in the stored water in the tank, then it may be time to replace the holding tank. 5. Water has foul odor Like dirty water, a foul odor emanating from the water can also be dangerous to health. ☑ Bad (but not sulfuric) smell Bad odors could mean bacteria, which can multiply in the growth-inducing hot water. This is typically resolved by flushing the tank. Experts also recommend replacing the anode rod to minimize the chances of any anaerobic bacteria surviving. ☑ Sulfuric smell This can be one of two things: The pilot light is out and needs to be relit. There is a problem with the gas line, causing it to leak and leach into the water. The first one can be resolved in the next section. The second one requires a professional visit from the gas supplier. 6. No pilot light The pilot light serves as the ignition source for the gas burner that actually heats the water. It is this part that ignites the gas flowing through the valve, which in turn lights up the burner. Problems with the pilot light can be caused by: A clogged or worn out tube, which needs to be replaced Loose thermocouple Trapped air in the gas line If the pilot light will no longer ignite, it could be due to: A defective pilot light, requiring replacement A damaged or broken gas valve In both cases, call a professional to resolve the issue. 7. Pilot light won’t stay lit If the pilot light goes on but keeps going out after a short period, it could be due to a faulty thermocouple. Replace the thermocouple, which is a relatively inexpensive part and is generally straightforward to install. 8. Unusual noises Popping or rumbling sounds can indicate blockage caused by sediment buildup or calcification. Drain and flush the tank to remove the sediment. Tank cleaning should be done annually to prevent sediment accumulation. 9. Water is too hot If the water continues to be uncomfortably hot even after adjusting the temperature, this could be a thermostat issue. Adjust the thermostat to the lowest temperature, and if the problem persists, the thermostat may need to be replaced. 10. Water leakage If you spot any leaks from the temperature and pressure relief valve, this means the water pressure may be too high. Check the home’s water pressure and adjust it if necessary. You may also consider installing a pressure-reducing valve to alleviate the pressure on the relief valve and prevent any more leaks. How to Reset a Gas Water Heater Some minor problems may be resolved by resetting the gas water heater. Here’s a step-by-step guide on how to reset a gas water heater. Shut off gas supply Turn off the gas supply to the water heater. This can usually be done by turning the gas valve to the “off” position. Wait a few minutes for any gas in the pipes to dissipate. Turn water heater off Find the thermostat on the water heater. It is usually located behind an access panel on the side of the tank or on the front of the gas valve towards the bottom of the tank. Turn the thermostat to the “off” position. Check pilot light Remove the access panel to view the pilot light. If the pilot light is out, which it should be since the gas supply is shut off, you will need to relight it. Follow the manufacturer’s instructions for relighting the pilot. This typically involves turning the gas knob to “pilot,” pressing and holding it down to start the gas flow, and then using a lighter to ignite the gas. Reset the thermostat Most gas water heaters equipped with a reset button will have it located on the thermostat. Press the reset button firmly. If you hear a click, the button has been reset. Turn on thermostat Adjust the thermostat to the desired temperature setting. Replace the access panel if you had to remove it. Restore Gas Supply Turn the gas valve back to the “on” position. Check around the gas connections for any signs of leaks. You can use a soapy water solution to check for bubbles at connections, which indicate a leak. If you find a leak, turn off the gas and tighten the connection or call a professional. Monitor the water heater Observe the water heater for a few minutes to ensure it is operating correctly. Make sure the burner ignites and stays lit. Listen for any unusual noises. Check for any leaks. Check hot water output Turn on a hot water tap somewhere in the house and check that the water heats up. Ensure the water temperature changes when you change the temp setting. Check that the water is free from smells or discoloration. Additional Reset Tips If your water heater frequently requires resetting or if the reset button trips again shortly after resetting, this may indicate a more serious issue, such as a malfunctioning thermostat or a faulty heating element. If the problem persists after resetting, contact a professional plumber or a certified technician to conduct the gas water heater repair. The Expert in Gas Water Heaters At Total Home Supply, we carry all types of hot water heaters from reputable brands, from storage and tankless models to point of use heaters and hot water recirculating pumps. If it’s time to replace your tired old water heater, check out our extensive selection and enjoy excellent service backed by our years of expertise in hot water heaters. Also check out our Water Heater Maintenance Guide for Tankless & Storage Units, to ensure flawless operation and make your gas water heater last longer! Mickey Luongo Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.
