Reconnecting an in-wall dryer vent can be a bit of a chore due to the lack of access to the interior space. A secure, consistent connection is imperative to minimize the fire hazard of a dryer vent and maximize the efficiency of the dryer. There are 3 types of dryer vent pipes: rigid aluminum, flexible aluminum and vinyl piping.
Vinyl piping should not be used, as is creates a fire hazard. When routing a vent through a wall, you will find it is likely easier to use flexible aluminum piping. Here are the steps you will need to follow to reconnect a disconnected vent pipe.
Step 1 - Consider Rerouting the Vent Pipe
If the vent pipe has come undone, now might be the time to consider re-routing the vent pipe all together. Check the manufacturer's specifications on your dryer for the maximum distance recommended for venting the dryer. Evaluate other routing options and see if there is one that makes more sense.
Step 2 - Disconnect the Dryer Vent
If the dryer vent pipe has been disconnected somewhere within the wall, it is worthwhile to remove the vent cover on the exterior of the home and see if it is easily reachable from that end. If you can not see it, disconnect the vent pipe from the dryer entirely and withdraw the vent pipe from the wall.
Step 3 - Snake a Line
Snake the wire through the opening for the vent pipe. Unroll the wire from the spool, and slowly feed it through the wall. Have a second person on the exterior of the home to receive the wire. Once they receive the end, stop feeding the wire and cut it.
Step 4 - Feed the Pipe through
Attach the wire to the vent pipe by poking the wire through the side of the aluminum and twisting the end up around the shaft of wire. Make sure it is relatively secure, so that it doesn't come undone in the process of trying to re-thread the vent pipe. Slowly have the person on the outside of the home draw out the length of the wire, being gentle and going slowly. The person on the inside should be holding onto the other end of the vent pipe to make sure that side stays put. If there are any snags hit, wiggle the wire and move it back and forth to dislodge the vent pipe. Continue drawing out the wire until the vent pipe emerges to the exterior wall.
Step 5 - Reattach the Vent Pipe
Reattach the vent pipe to the dryer using metal draw bands or a similar type of fastener that will hold securely. Secure the vent pipe to the exterior wall as well and reattach the exterior vent cover.