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What To Do if Your Tankless Water Heater Freezes

Posted On: January 23, 2023
Tankless water heater in garage

Winter in the Twin Cities is notorious for its brutally cold climate. If your tankless water heater is housed in your garage, it may be at risk of freezing, leaving you without hot water.

Though less common than frozen pipes, frozen tankless water heaters may need repairs or even replacement, so it is important that you not only know how to thaw your unit but also the steps you can take to prevent freezing in the first place.

Why Do Tankless Water Heaters Freeze?

Unlike traditional water heaters, tankless water heaters only produce hot water when you need it. While these tankless systems are highly energy-efficient and produce hot water instantly, they are at risk of freezing in cold weather because hot water is not constantly moving through the unit.

Many tankless water heaters have built-in freeze protection, but periods of extremely low temperatures or power outages can still result in a frozen system.

How to Thaw a Tankless Water Heater

If your tankless water heater freezes, do not attempt to use it. It is important to thaw the unit as soon as possible to prevent system and water supply issues by completing the following steps:

  1. Cut the power at the circuit breaker and close the unit’s gas and water valves.
  2. Attempt to warm the unit by turning on a space heater near the system.
  3. Once the system begins to thaw, open the water supply valve so that water can drain.
  4. Examine the unit thoroughly to ensure there are no leaks inside or in the external pipes.
  5. Once the water begins to flow normally through the unit, open the gas valves and flip the breaker back on.

If you notice leaks from the water heater or pipes, call a plumber, and do not attempt to thaw the system yourself.

How to Prevent a Frozen Tankless Water Heater

A frozen tankless water heater brings endless problems and may even require a replacement unit. However, there are ways to avoid being stuck without hot water.

If you expect temperatures to drop significantly in your area, consider these tips to keep your unit safe and running:

  • Run the hot water: The greatest damage in a frozen tankless water heater comes from the freezing and expansion of standing water in the unit. Run a small stream of warm water through one of your faucets to eliminate this risk. Remember that a slight increase in your water bill will still be far less expensive than water heater repair or replacement.
  • Prepare for power outages with a generator: Most tankless water heaters have built-in freeze protection. This consists of an electric system that melts ice inside the tank. However, this freeze protection cannot work properly if your home loses power. Safeguard this function during an outage by hooking your water heater up to a generator.

Choose Genz-Ryan for Plumbing Services in the Twin Cities

If your tankless water heater or pipes freeze, call Genz-Ryan Heating, Cooling, Plumbing & Electrical. Our licensed and insured plumbers provide the highest quality service in the Minneapolis-St. Paul Metro Area. Choose our team for 24-hour service and upfront pricing.

Call Genz-Ryan at (612) 223-6158 or contact us online today for plumbing repair or replacement.

Proudly Serving The Twin Cities!