Abstract: A heat exchanger having a housing for retaining a coil bundle, wherein the housing includes a first and second movable end for contacting one housing end with one end of the coil bundle and the remaining housing end with the second end of the coil bundle. The housing includes a sliding seal between the movable ends to permit relative motion between the ends while maintaining a sealed relation therebetween. Each movable end includes an aperture and a corresponding fastener for engaging the adjacent portion of the coil bundle to draw the coiled bundle against the respective end, thereby permitting removal of one end of the housing upon removal of a single fastener.