How to winterize a tankless water heater

One of the most common questions we get from seasonal cabin owners is how to winterize their Stiebel Eltron electric tankless water heaters. The best answer to this question usually depends on how you winterize the rest of the home. If the cabin temperature is kept above freezing, then simply switching off the breakers and turning off your water is sufficient. If the tankless will be susceptible to below freezing temperatures then other steps must be taken to prevent water freezing inside the unit and causing damage and / or water leaks.

Tankless winterization with non-toxic antifreeze

If you typically winterize your cabin by circulating a non-toxic antifreeze through the pipes and leaving it in over the winter, this is also a great option for your electric tankless water heater. Make sure you switch off the breakers before running the antifreeze through the unit as you don't want to heat it. Once the antifreeze has been circulated throught all the plumbing in your home or cabin, and your water has been turned off at the source you are ready for freezing temperatures.

Tankless winterization by removing and draining the unit

If you typically winterize your cabin by draining the water out of the plumbing lines, then extra steps are required to winterize your tankless water heater. The pipes inside a stiebel eltron electric tankless water heater run vertically, allowing water to be trapped inside when the rest of the plumbing is drained. If this water freezes it can cause damage to the unit. To make sure your Stiebel Eltron tankless is clear of water you should follow the following steps.

  1. Switch off circuit breakers
  2. Turn off water and drain your lines
  3. Disconnect inlet and outlet connections from your tankless (water may leak out at this time so be prepared with a bucket or rags)
  4. Remove the tankless from the wall and tilt on it's side until all water runs out
  5. You can then either leave the tankless disconnected (to be reconnected when you return to the cabin), or follow the steps in reverse order to reconnect it

PLEASE NOTE:
YOUR STIEBEL ELTRON TANKLESS WATER HEATER SHOULD NOT BE POWERED WHEN IT DOES NOT CONTAIN WATER.
OPERATING THE TANKLESS WITHOUT WATER INSIDE CAN DAMAGE IT.

If you have any questions please call our tankless experts toll free at 1-877-374-2696 and they would be happy to help.