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Cold Showers and Hard Water: Identifying Tankless Water Heater Problems

A tankless water heater has a lot of benefits for your home over a traditional water heater, including lower maintenance, better efficiency and endless hot water. A tankless water heater is not magic, as nice as that would be, and there are some common problems that can crop up.

Luckily, many of these common issues that can affect your water heater are easy to spot. Be aware if you experience these problems frequently, schedule a professional inspection or start to consider replacing your unit.

At Assurance Power Systems, we specialize in installation and maintenance of Rinnai gas tankless water heaters. For residents of South Florida looking to have an energy-efficient home, call us today at (561) 886-0470 or contact us online for a free consolation.

But no matter what kind of tankless water heater you own, these common problems can still effect your unit:


  • Ignition Failure
  • Cold Water Surprise
  • Mineral Buildup
  • Blocked Air Supply or Exhaust
  • System Overload Flame Failure


Ignition Failure

If it seems like your tankless water heater is not turning on at all, it could be an ignition failure. There are multiple reasons your water heater could have trouble igniting. Check to make sure the gas and water valves are fully opened. Check that your propane tank is full or that gas is coming from your utility. It might also be that your water heater’s ignition pack has failed and needs replacement.


Cold Water Surprise

If you’ve ever turned on your shower and stepped into warm water that suddenly turns cold before slowly warming back – you know this can be a very unpleasant surprise. This often happens when people take back-to-back showers. This is unfortunately a side effect of how a tankless water heater works. At the end of the first shower, hot water is still in the pipes. So, when the next person turns on the water, that warm water is first in line. Though tankless water heaters are thought of as instantaneous, they still need a little bit of time to heat up more water for the next shower. So cold water follows the trapped warm water. The only fix is run the shower a bit longer before you jump in.


Mineral Buildup

Mineral buildup is a problem for both traditional and tankless water heaters. Your water supply will have a different percentage of minerals depending on your home’s water source. You might know the term “hard water,” which just means water with a high mineral content. Calcium and magnesium will cause a white stain or scale to build up in tankless water heater, which can cause malfunctions or inefficiencies. You can fix this by flushing your water heater every six months with a descaler kit or add water softener to counteract the minerals.


Blocked Air Supply or Exhaust

To function properly, a gas tankless water heater needs unobstructed air flow to create the ideal environment for combustion and a way to get rid of exhaust from the system. Many systems monitor the air supply and exhaust, prompting an error code on the display if there is an issue. Examine the vent pipes for any disconnection or holes. Make sure your tankless water heater is not overcrowded by objects, which can block air flow. Also make sure the vents outside your home are clean and clear.


System Overload

A water heater can struggle if there is too much demand for hot water at the same time. This can cause your water heater to provide less hot water, struggle with water flow or even cause it to shut down completely. You can try to limit how many simultaneous demands there are, such as avoiding multiple showers. Your water heater will be limited by its capacity, so if you are finding you need more hot water at once, upgrading to a higher capacity unit might be wise. Others install two tankless water heaters to meet the needs of their homes.


Flame Failure

Similar to an ignition failure, the flame that heats your tankless water heater can sputter due to an electrical issue or a gas pressure problem. The flame failure can be caused by a low fuel level in your propane tank or an issue with your gas utility bill. The gas tankless water heater’s flame can also be effected by combustion issues, poor ventilation or a too small gas fuel line.


Still having a problem with your tankless water heater?

If none of the above problems seem to match what’s wrong with your water heater, it might be time to reach out for professional support. Call our team at Assurance Power Systems at (561) 886-0470 to schedule a service appointment.

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