top of page

FBC Office of Emergency Management Shares Tips for Thawing Out a Tankless Water Heater

(FORT BEND COUNTY) – The Fort Bend County Office of Emergency Management has shared tips for thawing out a tankless water heater following the deep freeze in the area projected to last through noon Saturday, Dec. 24.

“Water heaters freeze much less often than pipes in winter,” read the release. “Hot water flowing though the traditional water heater usually keeps it safe. But since a tankless water heater turns on only when you use hot water, it has inherently less protection.”

Steps to Thawing Out Your Tankless Water Heater

The most important thing to remember is – do not run a tankless water heater that has frozen.

It must be thawed out first, or you risk causing major damage. You will need to defrost the unit first, which requires the following steps:

  1. Check whether the water heater or just the pipes are frozen.

  2. Examine the inside of the heater for burst pipes (if this is the case, thawing out the unit will case a big mess).

  3. If the heater is frozen:

  4. Turn off the power and gas/water shutoff valves

  5. Disconnect the unit and move it to a warm area

  6. If necessary, turn on space heater near it

  7. Open the drain valve to let melting water escape

  8. Check for leaks in the unit and with external pipes

If the heater and pipes are in good condition, reinstall the unit and open the gas and water valves. Restore electrical power to the system.

Do not set the unit to its highest heat level; if ice forms, heating elements can overheat and catch fire.

How to Protect Your Tankless Water Heater from Freezing

  1. Turn off the gas supply.

  2. Turn off the water supply.

  3. Open the freeze protection solenoid valve.

  4. Open one or two hot water faucets.

  5. Remove the cold-water line inlet filter and, if there is one, the hot-water line plug or inline filter.

  6. Turn off the circuit breaker to protect the unit against surges or outages.

  7. Cover the vent intake and exhaust to prevent air flow issues.

  8. Insulate or wrap electric heat tape around pipes.


bottom of page