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Troubleshooting 10 Common Water Heater Problems

| Wednesday December 14, 2022

Have you experienced situations where your water heater has acted up out of the blue? Not sure about what exactly is wrong with your water heater or how to fix the issues you are experiencing? 

If so, there is no need to worry. We have compiled a few common water heater problems and ways to troubleshoot your appliance. Fortunately, water heaters are fairly simple products to operate and service. And, if any fixes or repairs are required, it usually does not result in burning a hole through your wallet. However, before performing any DIY repairs, it would be highly recommended to check if your water heater unit is still under warranty – if it is, it would be best to contact your contractor or the distributor you bought the water heater from to find out the best course of action to deal with the situation.  

Since there are many different types of water heaters in the market, to make things easier, we have divided the potential issues and ways to fix the water heaters into two sections: tank water heater problems and tankless water heaters problems. Tank water heaters and tankless water heaters operate fairly differently, thus, using a troubleshooting method for a tank water heater may not be relevant for a tankless water heater issue. 

Troubleshooting these problems is basically a process of elimination. We recommend working your way down the list until you find the issue that best resembles what you are experiencing with your water heating unit. 

Note: please make sure to turn off your water heater before proceeding with any repairs or troubleshooting. For electric water heater models, switch the heater off by using the service panel. For gas water heater models, switch the heater off by adjusting the thermostat to “off”. Please also remember to practice safety measures when inspecting the appliance yourself, if the issue is too complicated, it would be highly recommended to seek professional help instead. 

Rheem Malaysia will not be held liable or responsible for any damages to the appliance or person(s) doing any troubleshooting to their appliance. 

Tank Water Heater Troubleshooting

  • Water Leaks

If your tank water heater – or also known as storage water heater – is experiencing water leaks, below are some possible causes of the leaks. 

  1. Pressure relief valve — Replace the pressure relief valve to stop the leak.
  2. Ball valve — Tighten the nut securing the handle to stop the leak.
  3. Loose connection or stripped threaded nipple — If the leak originates from the top of the heater and is caused by neither of the above two points, a loose connection or stripped threaded needle is the likely culprit.
  4. Drain valve — Make sure the drain valve is closed properly. If that does not help to stop the leaks, replace the valve instead.
  5. Condensation — Switch off the heater for a few hours. If this solves the problem, lower the temperature on the thermostat.
  6. Tank — A leak from the bottom of the water heater that is not due to any of the above usually means the entire heater needs replacing. In this case, please contact your plumber or the distributor you purchased the water heater from to get professional advice on how to proceed. 

  • Low Water Volume

If your tank water heater is experiencing low volumes of water, below are some possible causes. 

  1. High-temperature limit — Push the high-temperature cut-off reset button.
  2. Heating elements — If the above doesn’t help, test each of the heating elements by touching the screws with a tester probe.
  3. Small tank — If you are experiencing a low water volume, it may be due to the capacity of the tank not being sufficient enough to cater to your household’s hot water needs. In this case, you may need to upgrade to a larger storage water heater. 
  4. Dip tube — Drain the tank and replace the dip tube.


For gas water heaters, also look at the following:

  1. Thermocouple — The thermocouple may need cleaning or replacing if the pilot light on the water heater continues to go out. The thermocouple acts as a safety device to prevent gas leaks, so, if there are any issues with the thermocouple, it would be highly recommended to get your water heating unit professionally looked at. 

  • Water Too Hot 

If the water from the water heater is coming out too hot even after adjusting the thermostat, it means that there may be issues with the thermostat. To fix this issue, change and replace the thermostat to a new one. If the issue still persists, it may signify that there is an issue with the pressure relief valve. To fix this issue, change and replace the pressure relief valve. If that does not solve the issue, consider flushing your water heater tank and replacing your water heater’s heating element. 

  • Slow Water Heater / Slow Heating Time 

If you are experiencing a ‘slow’ water heater, especially for storage water heaters, it may be due to sediments accumulating at the bottom of the storage tank. This is especially common for storage water heaters that operate in areas with hard or standing water. If there is an accumulation of sediments in the storage water heater, it would be recommended to do a regular flushing of the tank to make sure that nothing is stuck in the tank and causing it to operate inefficiently.  

  • Dirty or Smelly Water

Dirty, rusty, or smelly water is a sign that the anode rod in the heater needs to be replaced. Dirty water coming out of the water heater also indicates that there is a sediment and mineral buildup in the water heater’s tank. In this case, it would also be recommended to do a flushing of the tank. 

  • Noisy Water Heater

Look for leaks and check the pressure relief valve. If there are no leaks and the pressure relief valve is working fine, it would be recommended to clean the water heating unit. If you continue to hear noise coming from the water heater, you can also consider installing more insulation around the water heater. However, if the noise persists, it would be recommended to call a technician to get a professional inspection done. 


Tankless Water Heater Troubleshooting

  • Lack of Hot Water

Electric tankless water heaters may stop providing hot water because of a worn-out or faulty heating element, try replacing the heating element for a more efficient heating process. For gas tankless heaters, the problem is usually a switched-off gas valve or an obstructed vent. 

  • Water Too Hot 

In addition to a thermostat set too high or a broken thermostat, this can also happen due to a faulty temperature sensor. In this case, it would be best to call a technician to help repair or replace the necessary parts. 

  • Sediment and Mineral Buildup

While tankless water heaters are less prone to sediment and mineral buildup as it does not store any water in its unit, it would still be recommended to perform regular cleaning for the water heating unit. 

  • Smelly Water

This happens due to the presence of bacteria in the tank. Periodic flushing of the water heater may temporarily help but to fix the sulphur or rotten egg smell from your hot water, it would be recommended to replace the anode rod. If the smell is still there after flushing or changing the anode rod, call a technician to get proper help with this issue. 

When to Seek Professional Help

Sometimes, the problems above are just minor hiccups in the heater settings. However, there is a possibility that the problem you are facing with your water heater is much more complex and serious, especially if the troubleshooting you tried did not work. Problems may also arise if your water heater has simply reached the end of its life and getting an upgrade is the best solution. If you still want to continue using your existing water heater, it would be best to contact your plumber or technician for professional help. Additionally, if any of the issues and troubleshooting options are too complicated for you to try yourself, it would be strongly recommended to consult a professional for help. 


About Rheem Malaysia

Rheem has been a pioneer in developing innovative advancements in the water heating industry. With a long list of award-winning solutions, we have delivered comfort, savings, and reliability to our customers for decades.

Rheem Malaysia offers a wide range of water heaters for both residential and commercial uses. And, with over 1,000,000 water heaters installed across Southeast Asia, you can trust us to deliver quality, innovative, and advanced water heating solutions to suit your unique hot water needs. Find your perfect water heating solution today. 

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