To operate your existing Suburban Furnace with the Furrion Cube 18K, you need the Furrion Thermostat Adapter Kit along with the Furrion Chill Cube Ducted RV Rooftop Air Conditioner Single-Zone Wall Thermostat (models FACW13VSDA-BL-AM or FACC13VSD-AM). These parts are compatible and designed to integrate seamlessly with your furnace and the Furrion Cube system. Since you placed two separate orders—one for the Cube 18K unit and another for the thermostat adapter and thermostat—combining shipments may not be possible if the orders have already shipped. However, we do provide tracking information for all shipments so you can monitor delivery status. If you still need additional units or have further questions about your order, please contact customer service promptly to explore options.