Winter Protection

To protect your portable tankless water heater from freeze damage, either drain it completely after each use when temperatures are at or below 32°F (0°C), or pump RV-style plumbing antifreeze through the entire system. Both methods prevent water expansion that can crack pipes and the heat exchanger.

 

Why does freezing damage a tankless water heater

Water expands when it freezes at 32°F (0°C), which can crack the connected water pipes and the heat exchanger. This is a physical property of water, not a product defect.

Method 1: Drain the unit after each use

Drain the portable tankless water heater after each use when the outside temperature is at or below 32°F (0°C). Follow these steps in order:

1. Turn off the water supply and disconnect the incoming (inlet) water line to allow air into the system.
2. Open the drain plug at the bottom of the unit.
3. Keep the unit in a vertical, upright position so gravity pulls water downward and out.
4. Disconnect the outgoing (outlet) water line to allow all remaining water to drain fully from the heat exchanger and internal passages.
5. Leave the drain plug open and lines disconnected until the unit is ready for use again.

Method 2: Use RV-style plumbing antifreeze (recommended)

Pumping RV-style plumbing antifreeze through the entire system is the recommended method. It eliminates the need to disconnect or drain the unit after each use, and it ensures freeze damage will not occur throughout the winter months.

 

When spring comes, the process of switching back to water is simple. Just pump water back through the system, collect the antifreeze, and reuse it next season. This will not only save you money in the long run but will also make the spring startup process much smoother.