SHPI.zero is prepared for more sensors and additional hardware. It can easily be upgraded by you (requires some soldering) or ordered through our customization service. Optional parts are grayed out. A preliminary datasheet is available here.
3* Hongfa HF49FD 5A relays 5A switching capability, 3kV dielectric strength (between coil and contacts) Product information at hongfa.com. HVAC 24VAC power supply comes with four relays but without a current sensor.