Dear Fox ESS Technical Support,
I am having a Fox ESS H1 hybrid inverter installed as part of a solar PV and battery storage system. I wish to connect the H1 to a Vaillant aroTHERM Plus 7kW heat pump (controller: sensoCOMFORT VRC 720f/3) using the SG-ready protocol, and I would be grateful for clarification on the following points.
1. Does the H1 have a built-in dry-contact relay output for SG-ready signalling? If so, which terminals are used and what are the contact ratings?
2. If no built-in output is available, what Fox ESS accessory or external relay module is recommended, and how does it interface with the H1?
3. How is the SG-ready output configured — via the Fox ESS app, local inverter display, or firmware parameter — and what conditions (surplus generation level, battery SoC) trigger State 2 (encouraged) and State 3 (commanded) signals?
4. What signal cable specification (voltage, core count, cable type) is appropriate for the two-wire run between the H1 and the heat pump SG-ready input terminals?
5. Is there any known compatibility issue between the Fox ESS SG-ready output and the Vaillant VRC 720f/3 SG-ready input?
Any relevant wiring diagrams, application notes, or commissioning documentation would be appreciated.