A guide to gas water heater troubleshooting. The most common problems; symptoms and causes. Troubleshooting low performance, insufficient hot water, pilot light problems, improper gas combustion, issues with the pilot light, thermocouple, gas burner, venting, and other common issues.
Gas hot water heater troubleshooting guide will assume that the gas unit was correctly sized, professionally installed, per codes and manufacturers' instructions.
Note: Before contacting a plumber or the licensed HVAC technician for the problems related to your gas heater, recommendation is to read the gas water heater troubleshooting guide found here, and the instructions from the manual (if you still have one) as it might help you understand the problem better and assist you in repair.
If you need to inspect, test or repair the gas water heater always turn off the power, gas and water delivery to the unit.
Smoking and carbon formation and combustion odor are problems related to gas water heaters, and are very dangerous for the user, if not resolved. This is why the gas water troubleshooting article puts these problems at the top of the list. Such problems should be carefully analyzed and treated with caution.
Probably the most common problem, or complaint you will hear and find about water heaters, in general, is “no hot water.” So here are the reasons:
Find more details about troubleshooting pilot light problems here.
There are three, the most common causes of the condensation problem on gas tank water heaters:
Keep also in mind that the flue gases contain a large amount of water vapor, which is by its nature acidic. The acidic condensate can affect the metal surface by corroding it. It can usually be seen around the draft hood.
The condensation problem should be eliminated or at least reduced, as the excessive condensation can cause the pilot light outage, sizzling noise on the burner and puddle of water under the unit.
One of the simplest solutions for the water heater condensation is to increase the temperature settings if the temperature is too low.
Check if there is a gas leak. Mix the soap and water in a spray bottle. Spray it on the gas connections (you can also apply the mixture with the sponge or paintbrush). It is easy to recognize if there is a leak because bubbles will form. Use the pipe wrench to tighten the fittings.
The temperature setting could be set too high, but it is not heating water as expected, because the sediment build-up will act as an insulation between the gas burner and water, and will reduce the heat transfer.
Gas water heaters are similar to its electric counterparts; they utilize the water storage tank, insulation, dip tube, anode rod, and TPR valve, but use the gas burner for heating and venting system to remove the products of combustion.
If there is a need for hot water (the tap is open), the thermostat located in the gas control valve reacts allowing the gas valve to open the gas so the igniter can light the gas burner. Cold water that is delivered to the tank through the dip tube is heated at the bottom, where the gas burner is located. Hot water is now moved to the top from where it is delivered to the tap, shower or any other application (through the outlet tube).
The products of combustion are transferred outside using the venting system, which can be atmospheric, direct, power or power-direct, using the inside or outside air, and removing gases naturally or forced.
When the thermostat is satisfied, the unit is not working. However, when the temperature of the water drops below the set, the unit turns on.
Note: For a gas water heater to operate correctly there must be an unobstructed water and gas delivery, including electric supply (if it is required), the water tank should be filled with water, the proper amount of air delivered and exhaust gases removed.
This gas water heater troubleshooting guide is not meant for one specific brand or model; but it covers popular manufacturers such as Rheem, AO Smith, Bradford White, State, GE, Kenmore, American and other.
If you find problems, which are not presented in this troubleshooting guide, and you cannot solve them, it is recommended to contact a licensed plumber. If looking for the replacement parts use the genuine elements or from the trusted name, with the same characteristics, and per manufacturer's specs.
Regular maintenance and clean environment should be the first thing to consider when troubleshooting a gas water heater.