How do you make a rectangular aluminum downspout fit securely into a round PVC pipe that is attached to the system fan?
In order to fit a 3×4-inch rectangular aluminum downspout to a 4-inch round PVC fitting downstream from a system fan, one end of the rectangular downspout is made round by using a rubber mallet, a 3″ round PVC cap, and scrap 2×4 aluminum. The downspout is quite malleable and is easily made round; the PVC cap helps to make the downspout perfectly round and at the right diameter for the assembly. A bead of silicone caulk is then put along the inside of the fitting collar when assembling the downspout and fitting. Another bead of caulk is also put on the outside of the seam of these pieces, making the assembly air-tight. During routine operations and maintenance system inspections, that seam is inspected as well as all fitting seams where glue or caulk was used in the assembly. As long as the outside caulk bead is complete, the assembly is leak-free. A model of this fitting can be seen at the Pompton Lakes Remediation Project Information Center at 223 Wanaque Avenue in Pompton Lakes.
