Troubleshooting Water Heaters
Problem and Repair Guide
(updated 2017)

Troubleshooting water heaters, common causes, symptoms and home repair guide for tank leaking, no hot water, not enough hot water, cold water sandwiches, sediments, and scale build-up, noise, bad odor, gas valve problems, thermocouple replacement, and other water heating issues. How to get help!

Troubleshooting water heaters guide

What you need to know

Use this water heater repair guide to find out more about common causes and symptoms, how to identify problems and how to do repairs on tank type and tankless gas and electric water heating systems.

This guide can be used for repairing most of the water heaters sold in US and Canada including; Rheem, AO Smith, Bradford White, American, State, Kenmore, GE, Ruud, Whirlpool, Rinnai, Noritz, Takagi and other. Keep in mind that symptoms or signs of water heater failure among different manufacturers are very similar, if not the same, so directions for one brand and model can be applied to others.

To have a better understanding of propane, natural gas, and electric heaters, we recommend you become familiar with articles on how these units work and the main parts. Once you collect all the necessary information, the water heater troubleshooting gets much easier.

Heater's problems are not complicated to diagnose as they are usually obvious, and if DIY home and plumbing projects are not strange to you and you have necessary tools and the right guide, then you can successfully troubleshoot the water heater, without calling an expensive plumber.

Note: Troubleshooting water heaters that are using gas and electricity should be performed by a qualified individual, plumber or HVAC technician.

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Common problems - causes and symptoms

To make the hot water heater troubleshooting guide easier to understand and perform the repair, here are the common problems, causes and symptoms for water heaters failure, using propane, natural gas, and electricity as the fuel source:

  • Water heater leaking - the most frequent problem found in many consumer reports. The reasons for such malfunction might be that tank steel body had corroded sufficiently enough to cause a water leak, or it could be a discharge of the overheated water from the temperature and pressure relief (TPR) valve. If there is a puddle of water on the floor - find out how to fix leaking hot water heater.
  • Leaking or condensation - what is it? For proper troubleshooting keep in mind that condensation is often found on newer models as these units are more efficient than older ones and that typical heater will produce approximately one-half gallon of water vapor during every hour of work. Condensation usually happens shortly after the heater kicks in.
  • Puddle of water under the tank-type water heater is often related to water leaking and condensation. But what if there is dripping from the relief valve or a fixture, during the unit’s recovery cycle, when no hot or cold water is used. Find out what the cause of the dripping is and how to fix it.
  • Water is too hot or cold - faulty thermostat. Learn how to troubleshoot and replace water heater thermostat.
  • Troubleshooting strange noise in the water heater tank and lower performance - Sediment and lime build-up at the bottom of the heater tank and how to reduce it using the water softener.
  • Discolored, milky water and rusty hot water - anode rode is failing, corrosion inside the tank...
  • Smelly water such as Sulfur or rotten egg odor - bacteria in the tank as the result of the decomposing sacrificial anode. Chlorination procedure is often used to eliminate bacteria from the system. Water heaters that are not equipped with the anode or include powered rods do not have such a problem. See how to fix smelly water.
  • Water hammer is the hydraulic shock that is loud and destructive to the house plumbing and heater. Fixing this common plumbing problem is relatively easy.
  • If you have heard sounds such as ticking, clicking, humming or tapping noise, check out the heat traps and simply remove them. Heat traps are installed to increase the energy efficiency of the unit.
  • Noise inside the water heater is usually associated with two main conditions; water hammer and mineral build-up, but there are also other reasons for the noises such as pounding, rumbling, crackling, popping, ticking, sizzling...
  • "Pilot light goes out", or pilot outage is one of the common problems when operating gas-fired water heaters. Improper venting is one of the main causes - see why and what is the solution.
  • The temperature fluctuates from hot to cold and back. Check out the best way to have a comfortable shower with less "cold water sandwiches".
  • Bulging water heaters - common symptoms that are seen on the heater exposed to excessive pressure are cockeyed nipples of the top of the heater and bulged or reversed bottom of the head. See the solution to this problem and how to prevent it.
  • Tankless water heater malfunction due to freezing temperatures? Use this article and see how to avoid the problem with the proper winterizing.
  • Is the burner flame yellow and the flame is "lazy". Do you experience slow hot water recovery, the burner doesn't want to ignite, combustion odor, smoking and sooting, or burner flame floats. Then, check out the article "how to properly vent a gas water heater" and learn how to fix it. To avoid even more dangerous situation, did you check is there carbon monoxide emission that might lead to gas poisoning?
  • Does it take too long to get hot water at the kitchen sink or in the bathroom? Check out what is the cause and what you can do to get hot water faster.

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The first thing when dealing with the electric or gas hot water heater troubleshooting is to recognize a problem. Before the big problem occurs it is vital to understand what are the symptoms, does a heater have low performance, uncomfortable temperature, is it still efficient, does it deliver enough hot water, and finally troubleshoot and fix it on time.

Electric models are very easy to troubleshoot while fixing gas heater is more complicated, but if you know the heating process, unit's anatomy and have basic knowledge, the repair shouldn't be a problem. Tankless, due to the advanced design is even more complex, but since many models are equipped with the diagnostics system, troubleshooting gets easier.

With the proper problem diagnosing you will save time and money. I have seen and experienced many times that a solution for water heating problem can be very simple (like a blown fuse at the breaker), or easy repair by replacing the faulty element (heating element, thermostat...).

The recommendation is to perform the maintenance and service the unit regularly, because this is one of the best ways to prevent the problem on the heater, and even extend the life of the unit.

Preparing site for troubleshooting

Before trying to fix any of the problems shown above, here are more tips for troubleshooting water heaters and preparing the site for repairs.

  • Turn off both gas and electric power before working on the heaters.
  • Shut off the water supply to the heater.
  • Plug the garden hose to drain valve.
  • Prepare the necessary tools for service.

Keep in mind that the water heater failure and the unit's replacement can be easily avoided if the signs of a potential problem are identified on time. The symptoms or signs, list of potential problems and how to troubleshoot them are described in this article. Some of these issues are easy to fix; some require more time, knowledge and the right tools.

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