Various manufacturers use differing communication methods between HVAC appliances and the controlling thermostat. The important thing is that when controlling an HVAC load through the load management board you interrupt the 24V control wire that controls the entire system. With 2 stage systems or heat pumps, this is where these connections may vary. If you are unable to tap into the 24V system for the HVAC control portion of the load control board, a 50A or 100A Generac Load Managers may be used to interrupt the 240V wire providing power to the load.