furnace placement

86Scotty · 09-13-2012, 05:44 AM

I have had to change my furnace plans due to the location of a factory seat belt that I need to keep. I was going to put it right behind the right rear barn door, where I've seen many, but the vent of my furnace won't clear the factory seat belt box that is mounted there. I'm planning to move it straight across the van, into the bottom of my street side cabinet, but that places it about 1 foot behind the fuel filler hump (and the outer vent will be about a foot behind the filler cap on the outside of the van). I'm only asking because I've never seen one there. Is this a safety hazard do you think?
I can't really imagine why, but I've never seen one there. Plus, I don't think that my fuel cap would possibly leak hardly any fumes while parked, or that this little furnace would draw in enough pure fumes to make a difference, if they were present.
Anyway, is there something I'm NOT considering?

Scalf77 · 09-13-2012, 07:18 AM

I believe it is a RIVA safety rule not be within 36" of filler. Look for response from John K on this post. http://www.sportsmobileforum.com/vie...php?f=7&t=2246

It unfortunately does not give details to why.

-greg

dhally · 09-13-2012, 09:58 AM

We ran into this issue when locating our propane refrigerator near the fuel filler. We had to have our fuel filler relocated.

There is a real hazard created with a furnace or with a frig. When the appliance is operating, it is pulling in outside air and exposing it to an open flame. If the incoming air had enough gasoline vapors in it, it could ignite and the flame could follow the vapor trail back into the gas tank. Or imagine if the gas pump didn't shut down properly and gas was gushing out of the filler neck, with an open flame a few inches away. I have also seen a furnace backfire and blow flame out of the air inlet.

86Scotty · 09-13-2012, 10:01 AM

Hmmmmm. Thanks.
Im not sure I'm not going to do it anyway, but that's good to know. That really puts me in a bind. No other place for it.

86Scotty · 09-13-2012, 10:05 AM

Also, I'm not going to have a plumbed out system at this point and maybe never. There will be a quick connect under the floor and no mounted propane tank, so it could never come on while driving, but I see their reasoning.
Also, I just thought of 2 other builds I know of where the furnace is right behind the driver seat, definitely within 36".

Ford_6L_E350 · 09-13-2012, 10:12 AM

Sportsmobile wouldn't put mine there for that reason. It finally wound up raised off the floor and above the passenger side rear tire.

Another option maybe to get a ProPex heater. It is smaller and the inlet and exhaust are ductable to more remote locations.

Mike

jage · 09-13-2012, 12:53 PM

Quote:

Originally Posted by 86Scotty

Also, I'm not going to have a plumbed out system at this point and maybe never. There will be a quick connect under the floor and no mounted propane tank, so it could never come on while driving, but I see their reasoning.

I think sitting (collecting vapors) would be more dangerous than driving.

Quote:

Also, I just thought of 2 other builds I know of where the furnace is right behind the driver seat, definitely within 36".

Doesn't make it a good idea.

I recently noted that my spare fuel tray swings to the side of my furnace and water heater, both of which are in the rear corner and have open flames. Hmm.

I'd seriously look into Espar, SMB won't install a gasoline version but you skip the extra fuel source, it's smaller and therefore more locatable.

Or just move the fuel fill, I know of at least two rigs that have had it moved for the fridge!

86Scotty · 09-13-2012, 03:41 PM

Quote:

Originally Posted by jage

Quote:

Originally Posted by 86Scotty

Also, I'm not going to have a plumbed out system at this point and maybe never. There will be a quick connect under the floor and no mounted propane tank, so it could never come on while driving, but I see their reasoning.

I think sitting (collecting vapors) would be more dangerous than driving.

Quote:

Also, I just thought of 2 other builds I know of where the furnace is right behind the driver seat, definitely within 36".

Doesn't make it a good idea.

I recently noted that my spare fuel tray swings to the side of my furnace and water heater, both of which are in the rear corner and have open flames. Hmm.

I'd seriously look into Espar, SMB won't install a gasoline version but you skip the extra fuel source, it's smaller and therefore more locatable.

Or just move the fuel fill, I know of at least two rigs that have had it moved for the fridge!

Jage, I agree that it doesn't make it a good idea, but it has been done without immediate catastrophic results, so that makes me feel better.

I already have the furnace, it's an Atwood Evereststar (little black ventless box) and I'm out of real estate to put it with my new build. I really don't want it all the way in the back on either side, it just seems to me it wouldn't be nearly as effective in the back under a dinette/bed. Am I wrong?

Also, here's what I don't get. The risk is gasoline vapors getting sucked in to the furnace intake? It's a furnace right, it ignites propane already. I'm just not quite seeing how this would be a big deal, unless you had a MAJOR gas vapor problem, plus this doesn't even have a standing pilot. It's electronic ignition. Someone educate me please or I may proceed.

Thanks

Ford_6L_E350 · 09-13-2012, 04:31 PM

I agree, putting a furnace in the back, under a dinette/bed is a bad idea. SMB wanted to put ours there, I refused. If you are sitting there and it comes on, you will sweat, while the front of the van is cold.

Normally, there is no issue with a source of ignition near the fuel filler. Normally, you don't care if your smoke detector is working or not, 'cause there is no fire.

What if?? What if your fuel filler hose has a crack? What if some fuel leaked out when you filled it and you drove to a campsite and the furnace ignition caused the whole thing to go band and burn to the ground? What if someone tries to siphon fuel from your tank and some spills? There must be a million ways this can go bad, so 36" away from the fuel filler is the standard. Probably not a bad idea to follow that standard.

Can you raise the furnace up 6" or so to clear the seatbelts? You can always use the space to store shoes or something.

Mike

Ultrasport12 · 09-13-2012, 04:55 PM

I like many people have done all kinds of stupid things like using solvents in the garage near the piolt lights with no problems it does not mean nothing can happen or that you should do it.

Years ago when I lived in Upstate NY my good friend and neighbor Henry decided that he would stain his floors in his house and a warm winter day. He opened all of the windows and turned the furnace way down so it wouldn't come one while he was working. The fumes iin the house were very strong so after it was done he and his wife went out to dinner. Well guess what it got cold enough with the windows open that the furnace kicked on and the house blew up. It when up in the air enough to come down sideways on the foundation.

So will it happen, maybe not, but it could...
I know I am more careful now...

I would do what the company that makes the furnace says to do. If you have to mount in the rear maybe you could build some kind of duct work for it so the warm air will come out where you want it to. Better safe than sorry...

...Jamie