The SmartComfort by Carrier R4H4S Series Heat Pump offers exceptional performance. The unit, when combined with our engineered coils or air handlers, offers a full line of quality, split system cooling & heating equipment. Standard Features:System supports programmable or standard thermostat controls Scroll compressor Internal pressure relief valve Internal thermal overload Filter drierLoss of charge switchFilter drierBalanced refrigeration system for maximum reliability Solid, durable sheet metal construction Dense wire coil guard Longline up to 250 feet (76.20 m) total equivalent length, up to 200 feet (60.96 m) condenser above evaporator, or up to 80 ft. Low ambient cooling (down to 0F / -18C ) with approved low ambient accessory kits.