Diesel fumes and camp smoke drawn in by air conditioner

[Camper2209]

New to the RV world. Have a 2013 MB Sprinter class B. I am allergic to smoke so evenings in campground are a challenge. Windows are closed tight and air conditioner is turned on. If there are diesel fumes or smoke in certain areas around the van, they will be pulled inside the van.

Not sure how it is getting in or where the smoke/fumes have to be around the van for it to happen. Does not happen all the time, but when it does happen the air conditioner is always on. Any ideas why this is happening and how to track down the entry point?

[DSDP_Don]

You'll be surprised how much air comes in from your dash A/C. As "imgoin4it" stated, make sure your dash A/C - vent is in the off position.

[2oldman]

D & M wrote:
A/C units don't pull in air from the outside

If they did, it would never cool down the unit.

[D___M]

A/C units don't pull in air from the outside. The simply pass inside air over a cold coil. Nor do they creative negative pressure in the RV.

Here is a link to a thread that was posted several years ago that talks about self testing for leaks.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/18436339.cfm

[wa8yxm]

Trackrig wrote:
I thought the ACs just recycled air from the inside? It's a lot less work for the AC to further cool down air from inside than it is to pull in very hot air from the roof and try to cool it down.

Now if the vent is also open, that would pull air in from the outside.

Bill

I dare say 99% of the time you are right about "Just recycle" but as I said, I HAVE SEEN the odd exception. Very rare, but I have seen them. That said it has been a few years, long enough that it is very possible they do not make them that way any more.

However I also know that there are at least a dozen ways for air to enter my RV, there are many holes in the floor through which pipes, wires and other things pass.. Only a few of these holes (the ones I drilled myself) are sealed, Most pass into a basement compartment and the doors do not seal properly.

And there is the dash air vent, without vacuum it defaults to open-defroster. And there are roof vents in the bathrooms (I have 2) and the range hood vent.

lots of ways for fumes to enter.

[imgoin4it]

Make sure the dash air control is in the "off" position when you park. If left on vent or recirculation it leaves an open path direct from inside and outside. Max air or off are the only two positions that close the damper completely.

[ScottG]

RV roof top AC's are closed systems but some of them aren't built very good. I would go up top, remove the shroud and make sure the plenum isn't leaking. The newer ones are built much better but many of them (like mine) just rely on a bunch of duct tape at the edges and corners to seal them up.

[cochise49]

Check for open vent in bath or bedroom. Even a small crack will draw in outside air when AC is running. Sounds like some painstaking investigative work may be in order. Good luck and enjoy the journey.

[ed6713]

Possibilities
1) improperly sealing entry/ cab door/s. Take a dollar bill and shut the doors on it. Try to pull the bill out. It should be very snug. Now try this in a few more areas of the door. If the dollar pulls out with little resistance, the door is not well sealed.
2) do the same thing on each window. Very often, there is a seal where sliding windows meet when closed. Most often this seal is not air tight. No easy fix for this very common problem.
3) Crawl underneath. Look for any place where a wire or pipe enters the coach. Is the area well sealed? If not, a can of aerosol spray foam might be the answer.

Some RV places have a way to seal an RV them pressurize the interior. Then they spray a soapy solution around and look for bubbles that indicate escaping air.

Or, do as we mostly do. Go boondocking where your nearest neighbor is a mile away.

Enjoy your travels

Ed

[opnspaces]

A roof AC should not draw in outside air. The dash AC can draw in outside air. But it may be not be your ac actually pulling in the smoke.

Is it possible that the smoke always gets in as none of out RV's are air tight. But it's only when the AC is on and stirs up the interior air that you really smell it.

[Trackrig]

I thought the ACs just recycled air from the inside? It's a lot less work for the AC to further cool down air from inside than it is to pull in very hot air from the roof and try to cool it down.

Now if the vent is also open, that would pull air in from the outside.

Bill

[wa8yxm]

I HAVE seen air conditioners with fresh air intakes... Or stale air exhaust. However not many RV units have that feature.

IF yours does, make sure the air exchange doors are CLOSED (May be labled exhause, fresh air or vent but make sure it is CLOSED)

Next, Clean the intake filters.

ODDS are the offensive fumes are entering.... elsewhere, not via the A/C but the A/C may be assisting them in entering.

My A/C right now is working great, it's water cooled (It is raining again outside).

[DutchmenSport]

More than likely, fumes are coming in some other way. I thought RV air conditioners were closed systems, meaning, they only circulate air from inside the camper, unlike home window air conditioners that have a switch to flip so you can draw air from outside.

As stated above, campgrounds are not healthy if you don't have strong tolerances form fumes, smoke, smells, noise and light (Kind of makes anyone ask the question, why do we go there then?)

Funny, but true story:

Several years ago (our first TT) we were in a private campground that was located in a shallow valley, surrounded by trees in every direction, and a river running through it. No wind at all. Campground full. Evening, sun going down. Peaceful. Hot! Seems like everyone had a campfire that night.

Next thing you know, our smoke alarm went off in the camper as the campfire smoke was going right in the camper. Then the camper beside us, theirs went off. I looked up and the whole campground was filled with smoke. No air movement, like a fog, and getting thicker.

Then someone elses went off, then another, then another, and then another. People were scrambling to their campers by now to pull their smoke alarms and rip out the batteries to get them quiet. I did the same thing. It was comical, but then I realized, there wasn't a breath of fresh air anywhere, and realized how much we all were choking and coughing and couldn't get away from it.

We went inside, shut all the windows, turned on the air conditioner until we could breathe easier. We didn't go back outside that evening.

True story.

[midnightsadie]

when you stop at a Cg ask the host for the far a way spot ,tell them why.

[BuckBarker]

I have yet to see an AC that draws in outside air, but then again I haven't seen each and every unit.