A method of installing an exhaust tube is implemented by inserting an exhaust tube into an exhaust pipe that leads from the inside of a building to the outside thereof. Utilizing an already-placed exhaust pipe, a new exhaust tube is inserted into this exhaust pipe. The exhaust tube is installed according to a procedure of: performing, on the inside of the building, an operation of inserting a new exhaust tube into the already-placed exhaust pipe; performing, on the outside of the building, an operation of fixing the inserted exhaust tube to the exhaust pipe; and performing, on the inside of the building, an operation of connecting the fixed exhaust tube to an exhaust vent of a combustion apparatus.

A conduit locking device includes a housing having a first end, a second end, and a sidewall disposed between the first end and the second end. The conduit locking device may further include a slide engaged with the sidewall of the housing, the slide including an extension arm and an end portion structurally configured to engage with an inner wall of a conduit. The slide may be extendable via the extension arm from a first position substantially adjacent to the sidewall of the housing to a second position disposed away from the sidewall of the housing, where, when in the second position, the slide is configured to retain the conduit locking device at a fixed position within the conduit through the engagement of the end portion with the inner wall of the conduit.