Keeping A Tankless Water Heater From Freezing

How to Keep A Tankless Water Heater From Freezing

Even if the tankless water heater is designed for giving you hot water on demand, endlessly, it’s not going to be able to deliver when water in the lines freezes.

As a matter of fact, one of the many challenges for tankless units to handle the water loss happening when the pipes freeze.

When you live in a region with hard freezes always, there are a couple of tips to lower the risk for your tankless water heater for freezing.

What are the best ways to prevent the tankless unit from freezing?

Luckily for us, there is more than just one solution for protecting the tankless water heater against freezing. Here are the most effective methods:

  • Get rid of all standing water

Only because tankless water heaters don’t include a tank, doesn’t mean that water doesn’t get to stand in the system. When the weather is cold, the water will freeze eventually, and once it becomes ices, the internal elements of the unit present a higher risk for damage. If you plan to be away for more than 48 hours, you need to drain the water heater so that no water gets to freeze in the system.

Side note: High-end manufacturers create units that come with built-in freeze protection with the water heater. Here are some examples:

  • The tankless water heaters feature ceramic heaters on the heat exchangers, internal parts, and water parts that start operating once the temperature drops lower than 30 degrees.
  • When the temps drop suddenly, the units have a backup system for protection. A sensor will run when the internal temperature of the tankless unit goes too low. It’s going to cycle the water unit for a couple of seconds automatically. Once the water gets around 58degrees, the system cycles on and off until the risk for freezing is gone.
  • Have a continuous power source within reach

Freeze protection systems only run when there is a power supply.  When you cannot drain the system, it’s better that you install an uninterrupted power source that provides electricity to the protection system in case of a power outage. Battery backups and drain-down solenoids are great solutions.

  • Insulate the system

When you’re insulating the tankless unit, you reduce the risk of freezing. It’s time-consuming to protect the pipes, especially for areas with low levels of protection. Narrow and attic spaces are prone to freezing. You should use polyethylene wraps, heat tape, or fiberglass insulation for effective results.

Anyone living in areas that present freezing temperatures even before November should insulate the whole household.

Be aware that you have to use an electrical freeze prevention method when insulating the pipes (a heater will do). You need to lower the risk for freezing, no matter how cold it gets in your living area.

  • Think about installing a recirculation system

You can consider a recirculation system if the unit is compatible. The system will help you have hot water almost instantly, whereas in the winter maintains the plumbing system warm. It’s capable of reducing the risk of freezing. When the temperatures are freezing, the recirculation system is going to be an effective way of keeping the freezing possibility under control.

  • Try to maintain the plumbing system active

Running water is always going to freeze slower than water that doesn’t move. If you’ve tried all the previous methods and still worry about freezing, you should let a small amount of water running through the system at night. 1/10GPM is enough for maintaining most pipes protected against freezing.

There’s no need to turn on all fixtures, and one will do. You just need to make sure that the installation is connected to the tankless water heater.

  • Install the tankless water heater in a heated place

Should you mount the tankless water heater in a heated area, you can reduce the risk of freezing that may affect the system. When such a warm location isn’t available, you could at least look for a sheltered place to keep freezing at a distance. You also need to place the vents away from the area where winds typically hit your household. Don’t hesitate to build a small lean-to structure for protecting the tankless water heater. You can take the wind protection to the next level by incorporating the vent terminations.

Should you winterize your tankless water heater?

Winterizing the tankless water heater is an efficient method to protect it, especially if you’re planning to go away for the winter.

Always start by taking a look at the owner’s manual for the directions. Keep in mind that the instruction serves for general guidance, and some units may present particular requirements.

If you have a gas-fired unit, you should start by turning the gas off. Here’s what to do for the water supply:

  • Turn off the cold water supply to your tankless unit
  • Open the drain down (freeze protection) solenoid valves from the cold and hot water lines. You need to drain your unit like so
  • You should open a couple of hot water taps throughout the house
  • Continue with putting the inlet filter on the cold water line aside
  • You also have to put the plug/inline filter on the hot water side away. Make sure that there is some room for expansion in case there’s still water in the lines. Keep in mind that not every system comes with the fittings on the hot water line.

You also need to address the electric supply:

  • Begin with turning the power off to the unit. It depends a lot on the wiring of your system, but typically you flip off the circuit breaker or unplug the water heater.
  • When a power surge or outage develops, your tankless water heater will be protected

Anyone using a gas-fired tankless water heater should also take care of the vent system:

  • You need to put a cover on the end of the intake and exhaust vent. Do it only if you can reach safely.
  • It’s common for debris, leaves, and even small animals to enter the vent and get stuck. Airflow problems may develop when you’re restarting the unit, so check for any stuck leaves too.

One last piece of advice

Not everyone has the patience or the skills for winterizing the tankless water heater. Hire a professional plumber for the winterizing. He has to guarantee the work and even cover the spending when the task isn’t accomplished. Get the best out of it and sit beside him so that you know how to do it on your own next year!

Scroll to Top