Field Controls 46234800 SWGII-4HDRMK Stainless Steel Fan & Motor Assembly, For New & Old SWG-4HD & SWG-4HDS. Patented SWG or ComboVent Power Venters are ETL and cETL listed for all LP gas, natural gas, or oil-fired heating equipment. The SWG or ComboVent combines the motor, blower, and vent hood in one complete, easy to install unit. The SWG mounts on the outside of the building and pulls the combustion gases from the appliance through the outside wall utilizing 100% negative pressure.