5 Common Tankless Water Heater Problems and Solutions | San Antonio, TX

5 Common Tankless Water Heater Problems and Solutions | San Antonio, TX

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The innovation of the tankless water heater has resulted in more and more people in San Antonio, TX, replacing their traditional water heaters with tankless ones. Such heaters offer numerous benefits such as energy efficiency and space-saving.

However, there are some common problems that people face with tankless water heaters too. Let’s take a look at some common problems and their solutions, so that you know what you’re up against before making the final purchase.

Here are the 5 common problems attributed to tankless heaters:

  1. Overheating
  2. Mineral Buildup
  3. Cold Water Sandwich
  4. System Overload
  5. Frozen System

1.  Overheating

One of the most common issues with them is that they overheat easily if used for a prolonged period. So, if you use 7 to 8 taps simultaneously, it can build-up enough heat to damage the unit.


Check your thermostat setting. Don’t keep the temperature too high. Most of them operate best at temperatures of 120F or less. If the issue continues even after setting the temperature, get it checked for mechanical faults by a professional plumber.

2.  Mineral Buildup

You can receive fresh hot water within a matter of seconds. However, you’re the heater is prone to build-ups of inorganic mineral layers consisting of calcium and magnesium. This is almost a given in San Antonio, TX, where the water supply is usually hard, and contains minerals that will clog up your heater.


There are several measures that you should take to avoid mineral buildup. Here are some of the common solutions:

  1. Use a water softener to neutralize the pH level of water.
  2. Flush out your unit every 6 months or earlier depending on the hardness of water.
  • Clear the air intake filters to remove debris accumulation regularly.

3.  Cold Water Sandwich

People often complain that their shower goes from hot to cold to hot again. This is called the ‘cold water sandwich’ problem. It is common in family households where family members take showers back-to-back.


Understand that the water heater circles. Basically, as soon as the first family member runs the tap, the tankless water heater in yourhome starts heating the water. The person turns off the tap after the shower but some water gets trapped in the heater.

When the second member opens the tap, the trapped hot water starts flowing. Then, itrestarts its cycle. Therefore, after the outflow of the stored hot water is complete, the second family member gets cold water for some time.

So, in reality this isn’t a flaw. It’s just how the system works.

Now, the fact of the matter is that there isn’t any solution to this problem. They are quicker in providing hot water than traditional water heaters, but they aren’t instantaneous.

Thus, instead of taking the shower instantly, wait for the trapped hot water and cold water to pass go through until the uniform hot water supply starts.

4.  System Overload

While running several hot water taps simultaneously, the system gets overloaded and stops working. This problem occurs if you don’t install the right capacity of water heater in your home.

So, if you put more load than it’s capable of handling, it may not be able to tolerate the load. For instance, if you are using a tap in the kitchen and multiple showers at once, your system may not produce enough hot water and may stop working altogether.


If your tankless water heater, frequently gets overloaded, you have the following options:

a.    Upgrade the Capacity Power

Buy a new tankless water heater with an upgraded capacity. To get a proper estimate of the required capacity, you may call a professional plumber.

b.    Install a Second Unit

Add another tankless water heater in your home as a second unit. It will share the load according to your hot water demand.

If you cannot go for any of the above-mentioned solutions, try to limit the concurrent use of various taps. Instead of using a kitchen, shower, and garage water outlet at once, divide the work at different times of the day.

5.  Frozen System

Even though this problem is rare, but it is a serious problem. Just as overheating can be dangerous for your system, a frozen system is also an alarming situation. Winters in San Antonio, TX, can be tough, so you need to be concerned about this problem.

Homeowners face the challenge of water loss that occurs from frozen pipes. Because of frozen pipes, you wouldn’t be able to get a uniform supply of hot water.


If you think you will face such a situation then follow the following steps:

  1. Install your tankless water heater in a sufficiently-heated location so that it can receive a continuous supply of water.
  2. Remove any standing water from your tankless water heater especially in winter.
  3. Install a recirculation system.
  4. Keep an uninterrupted power source available.
  5. Insulate your system.

Bluefrog plumbing of San Antonio, TX, can help you with all your plumbing needs. We have expert plumbers to solve all your plumbing issues and can guide you to make the right capacity estimate of the tankless water heater for your home, flush it out to remove mineral buildup, and insulate it. Check out our website and book an appointment today!

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