Abstract: A sub-slab depressurization (SSD) radon reduction system uses an existing sub-slab refrigerant line chase as a vent pipe for suction of soil gas from a centrally located sub-slab suction point. A suction pit is excavated proximate the penetration of the slab by the chase, preferably by drilling and removing soil through the chase. The open ends of the chase are sealed with segmented end caps having two tubular sections, one for sealing around the refrigerant lines and the other for connecting externally to a soil gas evacuating air pump and internally to system monitoring instrumentation. A condensate dump assembly is located at the chase exit port.