Rinnai Tankless Water Heater Freezing (Fixed)

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Written By John Roe Stephen

A tankless heater might freeze even though installed in your house and is challenging to comprehend. This is what you’ll do to make things right.

You’ll need to take care of this problem since freezing may cause severe damage to your water and drainage systems. Do not even think of trying to use the device. This is what you can do to defrost a frozen tankless water heater:

  • Close the water heater’s gas and water cutoff valves.

  • Turn off the breaker to the heater’s power supply.

  • A few hours later, check to see if any water has leaked through the water supply line and shut it off.

  • Find signs of leaks in the device, its internal components, the plumbing, and outside pipes.

  • If water is flowing consistently, open the valves and re-energize the system.

  • Water heater leaks and other supply-line problems should be addressed as soon as possible by calling a plumber. Make sure you know what you’re doing before attempting to fix the gadget yourself.

How Does Rinnai Freeze Protection Work?

There is built-in freeze prevention in a Rinnai water heater. Water heater can withstand temperatures as low as -22 degrees Fahrenheit (-30 degrees Celsius) for indoor versions.

In contrast, for outdoor models, temperatures as low as -4 degrees Fahrenheit (-20 degrees Celsius) may be tolerated when connected to both electrical and natural gas sources.

 How Do You Keep A Rinnai Tankless Water Heater From Freezing?

During the winter, having water freeze in the heater is among the most frustrating things. When the water heater is switched on, it should provide hot water.

Water lines freeze, obstructing this process. Here are a few suggestions to keep your tankless heater from freezing if you have the same problem.

Locate Your Event in a Comfortable Setting

It’s preferable to keep the water heater in a warm or heated area so that it doesn’t freeze. Place your heater, for example, on a wall that is exposed to direct sunshine for the majority of the year.

This may also be done in a secluded area, the outdoors. Additional wind resistance is provided by including vent terminations in your design.

Drain Any Water That Has Accumulated 

If your heater has standing water and the heat is slowly lowering, make sure that it is thoroughly drained. When the water in the tank freezes, your heater is more susceptible to serious harm.

 If you are gone for further than 48 hours at a stretch, you should repeat this method. However, some sophisticated heaters include a built-in heating mechanism that keeps the appliance from freezing.

However, this functionality is only operational until the power is restored.

There Is No Interruption In The Power Supply

Your freeze prevention device requires a constant power source to function. So, if you live in a region with frequent power outages, you’ll need to find a way to keep the heater running. Using a battery backup or a drain-down solenoid may be helpful here.

System of Recirculation 

The recirculation system is compatible with many sophisticated water heaters. If you live in a colder climate, you may want to consider installing one.

Intriguingly, this technology aids in the maintenance of a more comfortable plumbing temperature.

This will almost eliminate the chance of water frozen in your heating system. – Contact the top water heater servicing companies to learn more.


Has the water heater ever been kept warm and functioning by using insulation? This method may also be used for your pipes. This is a common practice among homeowners.

The pipes in the basement and attic are the most susceptible to freezing. Contact a contractor to insulate your heaters using fiberglass, polyethylene, or heat tape.

Plumbing System Maintenance 

Running water, on the other hand, never freezes. In heaters, as well, the same idea holds. Make sure your plumbing system is up and operating at all times. Put the tap on for the night and utilize the water the following day if you’re in danger of freezing water.

When using a tankless heater, utilize the valve that is closest to it. The heating system might be severely damaged if your heater’s tank is filled with standing water.

When it freezes, this water expands, causing the most substantial harm. In contrast to outside facilities, indoor systems are less susceptible to damage.

 How Often Should I Flush My Rinnai Tankless Water Heater?

The walls of your tankless water heater’s heating chamber might deteriorate over time if the mineral buildup is allowed to grow. Flush the mines at least once a week to maintain & clean any tankless water heater.


Tankless water heaters can swiftly warm water with high-powered burners and heat exchangers. These systems do not need a tank to provide water to the faucets.

Energy savings of 30 to 50 percent are possible with tankless heating and cooling systems since they do not need a tank for water storage. Water heaters are substantially smaller and may be installed directly on the wall, making them ideal for smaller homes.

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