The H2 error is a result of an open heating circuit, resulting in, Mysa not detecting a heater load.
To complete the heater circuit please ensure:
- Mysa’s load connection is making contact with the heater supply connection; and
- Mysa’s L2 (N) wire is making contact with the heater return wire.
The other scenario is that the heaters return wire in the L2 or neutral bundles are not making contact with the other wires in the wire nut. If you need help determining your specific wiring configuration, check the guide.