Moving furnace vent...

[Safari Tim]

I need to relocate the furnace vent. The current vent exhausts on the end of the kitchen cabinet.

I simply need to extend the duct work a couple of feet and vent it out the front of my dinette seat. I am thinking of using the flexible tubing that is used on clothes dryers.

I'll need to form the transition from the existing vent to the new one. My current idea is to buy the dryer vent that has the tube on it, and remove the plasitc outer portion. Then screw that to the existing vent to give me a mounting point for the tube.

Here is the vent I'm talking about and I would remove the plastic hood.

Does this sound like it would work?

[Chuck]

you know, I was wondering how you were going to deal w/ this, since you posted about your dinette conversion.

you don't need to buy a dryer kit; you can get the tubing, both flexible and rigid, by itself.

I can't remember exactly how you configured your dinette...is the street-side seat right up against the kitchen cabinet? If so, you can just cut a hole in it, and put a register grate in the base of the seat. (kick plate? I don't know what you would call that part...the part right behind my heels, if I was sitting in the booth ). that is, if you don't use that space for anything else....there's plenty of pressure coming out of the furnace for that to work there.

Otherwise, I'd think you can get the pre-formed galvanized ductwork piece that forms a register. rectangular on one end, fitted to a 4" round pipe on the other.

[Safari Tim]

The bench seat butts right up against the cabinet.

I already put in a register cover on the front of the seat. Now I just need to extend the duct work from the original to the new one.

I want to use the under seat storage. So I tried using some metal to redirect the heat toward the register just like a make shift baffle. All that did was cause the furnace to over heat and shut down with the safety. Plus the metal under the seat got exteremly hot to be able to use the area.

I could try and just remove that metal for now and see if the furnace would not overheat.

I'll have to hunt around the home store some more to see what I can find. We don't use the furnace so it's not a priority. I just like having everything working correctly.

[TomW]

I do not believe a single wall tube will be suitable to safely carry the heat a furnace will produce.

Check your home improvement's water heater supply aisle, and see if they have any flexible double-wall tubing in the length you need. Even the double-wall stuff can get warm after a while.

Tom

[flyfshr]

What type of ducting is now in use by the original furnace? Can't you locate more of the same and use that? Seems the under seat storage has turned into a bread warmer.

FF

[Safari Tim]

That's just it. I'm not sure. Its a rectangle duct, probably galvinized steel? Whenever I go into the home center, I have no idea where to look.

Originally Posted by flyfshr

What type of ducting is now in use by the original furnace? Can't you locate more of the same and use that? Seems the under seat storage has turned into a bread warmer.

FF

[flyfshr]

OK, after a little internet searching, I realized this stuff is harder to find than I would have expected. Lowe's or Home Depot have a limited amount of ducting material. Ace has a few more options but still limited. At least through their on-line catalogs. Try this place out www.ductmonkey.net They have a variety of metal ductwork available if that's the way you need to go. Seems the newer models of RVs use the flexible and insulated material though.

Sounds like you need an elbow that would hook up to your existing venting where it previously exited the galley and now needs to exit out the kickboard under the dinette. It will probably need a same size and shape extension on the original vent before the elbow.

I drew you up what I have in mind but it keeps tellling me the file's to large. I'll keep trying.

FF

[flyfshr]

Going to try this again in PDF format. Wish me luck...

A good sheet metal shop could make one of these to your specifications in no time at all. Cost of materials would be minor. Maybe a local sheetmetal worker's union could hook you up with an apprentice?

FF

[Chuck]

I'm thinking that you want to flip that around, and mate the square part labeled "register" with the existing register. The furnace in mine (assuming Tim's is identical) is right up against that cabinet wall...there's almost no ductwork there at all; it just blows straight out of the furnace through a very stubby piece of ducting at the base of the cabinet. that's why it comes out so forcefully; no resistance. almost nothing comes out of the aft register, which is under the streeside bunk in mine, 10 or 12 feet away. in order to get any airflow out of that one, I have to practically close off the galley register w/ the thingies on the register grate. and there's STILL alot of air coming out of it. Which is why I said before, just a hole in the base of the dinette seat would work...there won't be any problem with airflow. But it would heat up the whole compartment in there. Maybe a "false bottom" in that seat that would confine the warm air to the space underneath. then a hole and register grate to allow the heated air to escape into the living space.

here's a crude drawing of what I'm thinking....

[Safari Tim]

You guys have the right idea. That is why I was looking for that flexible vent tubing like flyfshr was talking about but I just don't know what its called or where to get it.

I would like to keep the area under the seat for storage, so I added a few sheets of metal flashing to direct the heat out the new vent, but it got so hot you would not touch it. Which will not work

I guess what Chuck is saying it to remove that flashing, and just allow the heat to find its way out. But I'd rather direct it out so I could keep the storage.

Seems like this would be a lot easier than I'm making it

Here is a picture. Note the dark brown vent opening I added to the front of the dinette seat when I built it. The furnace/vent configuration is exactly as Chuck describes.

[Safari Tim]

Chuck, in looking over your picture with the false bottom, I think I understand what your getting at.

Would it be safe, heat wise, to make that false bottom out of wood?

I like this idea.

Originally Posted by chuck

Maybe a "false bottom" in that seat that would confine the warm air to the space underneath. then a hole and register grate to allow the heated air to escape into the living space.

here's a crude drawing of what I'm thinking....

[Chuck]

hmmm...I don't know. but I can tell you, I have forced hot air in my house, and one of the registers comes up under a kitchen cabinet. they just put a grate into the kick plate. no problems in 11 years.

the air isnt' that hot, though...much farther away from the furnace. maybe if you attached a layer of that foil-bubble insulation, that seems to be so popular?

[thenewkid64]

Make it out of half inch ply, and before final assembly staple some lightweight flashing material to the inside surfaces. The metal will help to reflect the heat. And if you really want to, you could insulate with the foil bubble stuff between the metal and the wood.

I wish I had known that you were in need. We tossed all of the fancy duct work that was in Vintage Thunder and I bet there was some that would have worked

[Safari Tim]

That's a good idea.

Another project. Yeppie

Originally Posted by thenewkid64

Make it out of half inch ply, and before final assembly staple some lightweight flashing material to the inside surfaces. The metal will help to reflect the heat. And if you really want to, you could insulate with the foil bubble stuff between the metal and the wood.

I wish I had known that you were in need. We tossed all of the fancy duct work that was in Vintage Thunder and I bet there was some that would have worked

[bryanl]

Most RV furnaces have standard 4" diameter plenum attachments at the side or a slot on the bottom. My 76 28' uses the bottom plenum hole to feed the trailer ducting.

Your rectangular duct, if its like a 78 31' I worked on recently is just an adapter to convert two round furnace outlets to a rectangular vent placed only a couple of inches from the furnce sidewall.

You can get the adapters for the furnace that will allow you to attach 4" flexible ducting ($1/foot at the local RV place here) to the round plenum holes. It is a simple flange thing that fits into the indents on the furnace holes.

You can also get round vent outlets to put on the other end of the vent tubing. They only cost a couple of bucks and come with adjustable air diverters. Put in one for each furnace plenum outlet that is not otherwise used to get good airflow out of the furnace.