How to Keep a Tankless Water Heater from Freezing
A tank-based water heater always has hot water in it, so it’s less likely to freeze in winter. However, a tankless water heater does not have this advantage. It only runs when you use hot water. But if the unit freezes, there are safe and effective ways to thaw it. You can even prevent freezing from occurring in the first place.
What’s the Risk of Your Tankless Water Heater Freezing?
A tankless water heater’s susceptibility to freezing depends on the model and its location. Units located outside are inherently more at risk. Many brands include dedicated heating elements that warm up internal components when the temperature drops below freezing. Some use a temperature sensor that triggers the unit to turn on and warm up. But such a unit can still ice up if there is a power outage.
Methods to Prevent a Tankless Water Heater from Freezing
A tankless water heater may be less vulnerable to freezing if you take the following steps:
- Install It In a Sheltered, Well-Insulated Area: If you can, place an outdoor unit in an area blocked from the wind. An isolated location is likely to have warmer air. Installing a tankless water heater cover for winter is another option; it will protect the unit from the coldest temperatures, not to mention snow and ice.
- Run a Faucet on Low: Water is more likely to freeze when not in motion. To reduce the risk of freezing, run a faucet at a low level during extreme cold. A flow rate of about 0.2 gallons per minute can protect your tankless water heater. If you’re concerned about wasting water, collect the water in a bucket and reuse it.
- Connect the Unit to a Generator: Hook the tankless water heater to a generator so the built-in freeze protection feature is powered. Set up a small, portable generator for emergencies if you don’t have a whole-house generator or your water heater isn’t connected to it.
- Install a Solenoid Valve: A solenoid valve will open automatically if there’s a power outage so the tankless water heater will drain itself. Solenoids stay closed as long as an electric current is flowing and open when there is no electricity. Therefore, your system is protected against freezing if the power goes out during cold weather.
- Drain the Tankless Water Heater: To winterize the unit, manually drain it by turning off the cold-water supply, gas supply, and temperature control. Next, turn off the circuit breaker to the unit. To relieve pressure, open a hot water tap, place a bucket under the water heater, and open the drain caps and hot/cold isolation valves. Remember to also remove any inline filters and cover the vent intake and exhaust (to prevent issues with airflow).
- Insulate the Tankless Water Heater Pipes: The pipes can be protected by wrapping them with an insulating material. Electric heat tape also can be used. These methods will prevent the coldest air from reaching the pipes and causing the water in them to freeze.
Never set a tankless water heater to its highest heat setting. If the unit does ice over or ice forms inside it, the heating elements can overheat, possibly causing a fire.
How to Thaw Out a Frozen Tankless Water Heater
If your tankless water heater is frozen, do not attempt to run it. Defrost the unit first or else you risk causing major damage. To get started, check if only the water heater is affected or if the pipes around it are frozen too. Open the panel to the unit to check for burst pipes. If any pipes are damaged, call a plumber. Thawing out the heater may cause a flood.
If the issue is isolated to the water heater, turn off the power. Next, turn off the gas and water shutoff valves and disconnect the unit. Relocate it to a warm room or use a space heater if you can’t move the water heater away from a chilly area. Once the unit starts warming up, the ice should melt. Open the drain valve so melting water can escape. Meanwhile, check for leaks in the water heater and the pipes that supply and drain from it.
You can reinstall the unit if all components appear undamaged. Open the gas/water valves, restore electrical power, and test the unit to make sure it’s working properly.
Call Village Plumbing for Tankless Water Heater Repair
Our tips can keep your tankless water heater from freezing and help you thaw it out. But ice can damage sensitive components. Water expands when it freezes and there’s little room inside the unit to accommodate this process. Our technicians are trained to address freezing and provide any water heater repairs you need. You can reach us 24/7 in an emergency. If your tankless water heater is frozen, contact us online or call (713) 678-0483