A process for installing a liner in a generally horizontal pipe section includes the steps of: providing a hollow generally cylindrical folded pipe liner having a reduced cross section sized to allow the liner to be slidably drawn into the pipe section from an upstream end to a downstream end; pulling the folded liner through the pipe section leaving end sections of the liner extending from the upstream end and the downstream end of the pipe; snaking a pull wire through the liner; pulling an air hose and a steam hose through the folded liner from the downstream end to the upstream end; providing a floating plug assembly including at least two disk shaped expanders; attaching the steam hose to the floating plug assembly downstream of the disk shaped expanders; attaching the air hose to the floating plug assembly upstream of the disk shaped expanders; inserting the floating plug assembly into the liner at the upstream end; and providing steam to the steam hose and cooling air to the air hose, while pulling the floating plug assembly through the liner to progressively heat the liner to a softening point downstream of the disk shaped expanders, and expand the liner to fill the pipe and cool the expanding liner upstream of the disk shaped expanders.