Common Problems With Tankless Water Heaters

July 21, 2023
Homeowner Examining Water Heater after Tankless Water Heater Repair in Belleville, ON

Tankless water heaters are becoming increasingly popular, but even they have their drawbacks. While they may have a longer lifespan and provide more consistent hot water than traditional tank water heaters, there are some common problems that you should be aware of that could occur.

Flame Failure

Flame failure can be caused by a variety of factors, including low gas pressure, improper ventilation, or a faulty flame sensor. If your tankless water heater is experiencing frequent flame failure, it may need to be serviced by a plumber to ensure the correct pressure and ventilation.

Lime Scale Buildup

Hard water can lead to limescale buildup inside your tankless water heater, which can reduce its efficiency and cause costly repairs. It’s important to have your tankless water heater serviced regularly to prevent lime scale buildup. To prevent lime scale buildup, consider installing a water softener system.


Tankless water heaters are designed to provide a steady hot water supply, but they can become overloaded if too many fixtures are running simultaneously. If you’re experiencing frequent overloads, adding more tankless water heaters, or reducing the number of fixtures running at once may be necessary.

Cold Water Sandwiching

Cold water sandwiching is common with tankless water heaters, especially in homes with multiple bathrooms. This occurs when the hot water from one fixture is consumed before the hot water in another reaches it, resulting in lukewarm or cold water. To reduce this likelihood, install a larger tankless water heater or split the system into two separate systems.

Air Supply Blockage

Tankless water heaters require a constant air supply to function properly. If your tankless water heater has low performance or is not producing hot water, it could be due to an air supply blockage. Make sure there’s plenty of ventilation around the heater, and check for any blockages in the air supply lines.

Tankless water heaters require regular maintenance to ensure they are functioning optimally. If you encounter any of these common problems, contact a licensed plumber from Quinte Air Supply to have your tankless water heater serviced and prevent further issues from arising. We can also help you with AC installation and repair, heater installation and maintenance, water heater installation, indoor air quality, and ductwork in Belleville. Contact Quinte Air Supply today to schedule an appointment!

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