Furnace gap around mounting hole

[steve and Melanie]

Hey everyone been a minute we just took the intake grill for the furnace off and noticed the flooring was heat shrunken
Apparently the factory made the hole to big and the discharge side was taped to the floor
Wondering what we can use to seal the gap z a I’ve enclosed some pictures any advice would be appreciated

[persistent]

Do what ever is necessary to close the gaps using sheet metal. Various sheet metal techniques can be used.

Do not use "Duck" tape to seal leaks. It is not heat resistant. There is a metal tape that can be used on cold air returns, but the adhesive is not heat resistant either.

Do not allow any plastic or vinyl products to come in contact with the hot metal ducting or to be inside the duct space.

Vinyl exposed to hot air must be shielded using sheet metal.

[steve and Melanie]

Hey thanks for the reply we went to our local HD and got some sheet metal made a couple of S pieces and sealed the gap no idea how to get the inside gap without removing the fifth wheel basement wall

[videoarizona]

If the transition piece is pulled away around it's circumference, suggest you take it off the main duct. Either taped and screwed or just taped. If screwed, they are simple sheet metal screws.

Repair flooring all around hole. Then put the transition piece back in place, sealing it well.

That's my guess based on the 2 pictures.