The 48 PM centurion developed by Carrier is a gas heated and electrically cooled rooftop unit made from the Puron Refrigerant technology as well as the Novation Heat Exchanger patetnted technology.With very low sound levels of around 92dB and with effective operating capacity the unit provides very good reliability. Maintenance of this product is also easy. Some of the units are prewired as well as precharged with the Puron HFC refrigerant.These refrigerants have been tested and are proven to be environmentally sound and stable.All the units put for sale are factory tested for environmental considerations and if any defect arises, they are stopped from loading.It also consists of a belt drive motor that has an adjustable belt system as well as a quick pulley for support.With a ondensate pan that is internally sloped, the device provides a cooling upto 125 degree F.With gas efficiencies provided upto 82%, the 48PM is a universally accepted product and has been certified by both UL as well as ARI standards of certicification and check.