Error A121 means the Shut-Off Valve has malfunctioned. The following steps can help you check the issue.
- Check connections of the wiring.
- Unplug and plug back the Shut-Off valve.
- If the alarm persists, call customer service.
Zwell is dedicated to getting homes closer to net zero through the installation of new energy-efficient hybrid water heaters. We are not currently equipped to do service or repair visits but we want to be as helpful as possible. Feel free to reach out to us here or for more information, you can contact the Rheem Hybrid Technical Services Department at 800-995-0982.