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