I am redoing my generator exhaust. Before it just ended under the bus. I was not sure of its safety and did not use it while parked until I bought a CO sensor. It did show that CO was getting inside. I used the generator on the road though with no problem. Anyway, I am running a pipe out the side. My idea is to let it poke out on the side just below the generator radiator. My thought is that, as the exhaust is expelled, it will rise and be blown away by the wind coming from the radiator. Does that make sense to you? Also, how far should the exhaust pipe extend beyond the side of the bus?
I ran mine back just in front of the drive tires.
This will allow a stack and still have access to all the bay doors.
see picture = 1 is generator 1 is proheat.
my genset pipe extends about 5 inches beyond the bus. i also have one of those attachement stacks to get the exhaust, and noise to the top of the bus. we mount it over the pipe, then strap it to a couple screws on the side of the bus. all of the exhaust and most of the noise to the sky instead of your neighbor.
Mine also runs out through a hole in the expanded metal door gen door. This works fine underway and while we are awake, but I don't trust it enough to sleep while it is running.
I eventually plan to rig a rooftop level exhaust extension with an elbow attachment at the present end of the pipe like the above post.
Well, I went ahead with it after consulting the experts in the chat room. I cut the pipe about between 4 and 5 inches out. I figured I could always reduce it later if I wanted.
Ed, I like the picture of the way yours looks, especially since it does not interfere with the bay door. I did not really consider that, but I wanted to go the shortest route anyway for now. Although I have not tried it yet, I believe my extension will leave the door usable anyway. I'll check that tomorrow and maybe take a picture. The most important thing is that I let the generator run for awhile and the CO sensor stayed on zero.
Is it alright to use a hard connection to the end of the pipe for support or should there be a little rubber in there to limit vibrations? It does not seem to vibrate much anyway.
Lin,
Mine doesn't stick out but about two inches. I did this because it is long enough to attach an extension but mostly because I didn' want to peel off the skin on my shins. That exhaust end is wicked.
Depending on how long the whole exhaust pipe is it doesn't need rubber for vibration as long as it is attached to the gen and vibrates along with it.
If the pipe is pretty long it needs a flexible hanger to allow for expansion of the pipe length when hot.
Does your generator have a short flexible section of exhaust to absorb vibration? Ours has one about 16-18" long that attaches to the exhaust manifold. The exhaust pipe attaches to the other end of this flexible section. We used hangers with the rubber sections because our exhaust runs about 18' before going through the muffler and exiting rom under the bus on the driver's side in front of drive axle.
As was mentioned, we only have our exhaust sticking out about 2-3". I hates banged up or burned shins. Jack
Quote from: Lin on August 14, 2008, 08:42:32 PM
Well, I went ahead with it after consulting the experts in the chat room. I cut the pipe about between 4 and 5 inches out. I figured I could always reduce it later if I wanted.
Ed, I like the picture of the way yours looks, especially since it does not interfere with the bay door. I did not really consider that, but I wanted to go the shortest route anyway for now. Although I have not tried it yet, I believe my extension will leave the door usable anyway. I'll check that tomorrow and maybe take a picture. The most important thing is that I let the generator run for awhile and the CO sensor stayed on zero.
Is it alright to use a hard connection to the end of the pipe for support or should there be a little rubber in there to limit vibrations? It does not seem to vibrate much anyway.
EXPERTS? CHATROOM? ARE WE TALKING ABOUT THE SAME CHAT ROOM? The one here on this board?
OH shoot HOLY CRAP you'd hurry up and undue that exhaust before your better half flushes the toilet, it'll be smokin' fer sure! I know most off those guys that hang in this chat room, and they probably told ya to hook it to the "exhaust vent" for the toilet! LOL! ;D BK ;D
Lin, I come out the side from my unit which is in the 1st bay my exhaust is by the rear bogie(13ft) on my Eagle I just swing mine up to what looks like a gate lock, install the burn protection (chrome expaned metal from a truck) on the pipe like killing 2 birds with 1 stone.If you have window awnings watch out for that not fun to redo when a awning is where you need to go up
Quote from: Busted Knuckle on August 17, 2008, 07:43:05 AM
Quote from: Lin on August 14, 2008, 08:42:32 PM
Well, I went ahead with it after consulting the experts in the chat room. I cut the pipe about between 4 and 5 inches out. I figured I could always reduce it later if I wanted.
Ed, I like the picture of the way yours looks, especially since it does not interfere with the bay door. I did not really consider that, but I wanted to go the shortest route anyway for now. Although I have not tried it yet, I believe my extension will leave the door usable anyway. I'll check that tomorrow and maybe take a picture. The most important thing is that I let the generator run for awhile and the CO sensor stayed on zero.
Is it alright to use a hard connection to the end of the pipe for support or should there be a little rubber in there to limit vibrations? It does not seem to vibrate much anyway.
EXPERTS? CHATROOM? ARE WE TALKING ABOUT THE SAME CHAT ROOM? The one here on this board? OH shoot HOLY CRAP you'd hurry up and undue that exhaust before your better half flushes the toilet, it'll be smokin' fer sure! I know most off those guys that hang in this chat room, and they probably told ya to hook it to the "exhaust vent" for the toilet! LOL! ;D BK ;D
Aw, Bryce, we were only funnin' him! and besides, we wanted to see if the heat from the exhaust would get rid of the gas from the waste tank.
Oh, and we did tell him to put a water tight rain cap on it for whenhe's parked or goin' down the road!
-DF
Actually, I knew a mechanical engineer that was basically employed full time for a while doing things to a guys motorhome. One of the things they did was build a system that fed the black water into or onto the exhaust while traveling down the road. He claimed it worked well except for creating some buzz on the CB from truckers he passed.
Lin,
I am a little surprised that more folks didn't chime in to reinforce Jack Conrads "suggestion" that you include a piece of FLEX exhaust pipe in your design. My pipe did fine until I lengthened the pipe and put on a bigger and heavier muffler. By adding weight to the ex plumbing I reduced the pipes ability to "follow" the genny. So they flexed at the manifold connection. The result was that the pipe developed a hairline crack at the manifold joining. It didn't hiss or make any other audible noise and I was clueless that it was pumping CO into the gen compartment. I still don't know how it got from there to the interior but it DID. One of the engine ex pipes on the rear of the DD is flex and it only travels a few feet and is hefty round. Without that flex it would eventually crack, I have not a shred of doubt. All the pipe on a auto/truck system is hung with rubber. Noise is one purpose but metal fatigue and cracking is another. I think tort law has had a great influence on this cause you only have to kill a few hundred family members and guys like me sitting on a jury will make sure a manufacturer learns the lesson and even rubber mounts his butt.
My advice: Flex pipe at the manifold pipe joining (ala Jack). Rubber hangers for the pipe. Vert pipe extension to roof height. CO sensor inside the coach.
Wishing you a safe journey,
John
Just when I thought I had it all sewn up! Well, it does not look like it will be so difficult to add some flex. Here's the pictures. The hose can be used to get to the roof or just away on the ground. A three inch hose may be a bit large, but I already had a couple. Note though that the muffler is resting on a plate on the bay floor and can move a bit in all directions.
Lin,
How hot do your exhaust gases get?
I would be concerned using the hose. What type of hose is it?
Just a thought.
Paul
It is exhaust hose that is used in shops when working on vehicles indoors. I originally bought them when I had my other bus inside. I used them if I wanted to run the bus or the generator. They work fine. It's similar to this:
http://cgi.ebay.com/ebaymotors/Crushproof-Tubing-Garage-Exhaust-Hose-Vent-3-x-11_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQcategoryZ63700QQihZ018QQitemZ280213779745QQrdZ1QQsspagenameZWD1V
I figured it would be the right stuff!
I shoulda known. ::)
Great idea, bet it stores up real nice too.
Paul
My exhaust system is very short. The muffler is bracketed directly to the bottom of the gen and the end of the exhaust is held by a flexible clamp to the sled supporting the gen since there is some slight movement between the gen and sled.
I wouldn't place the muffler directly against anything metal because it gets so hot, even with heat protection wrapped around it. The heat transfered to the bus metal frame can be tremendous.
My old gen was bad at heating the bus frame so I made sure the new one was well insulated.
We use a CO Detector inside the bus and our exhaust exits right under our bedroom window. We have spent MANY nights sleeping above the running genset and are still alive to talk about it. But you typically have the windows closed and the AC on when you are running the gen.
I think the CO detector and the windows closed are the key here.
Many of these times we are where other diesel trucks are running all night like rest areas etc.
HTH
Melbo
Gus,
I have not noticed any serious heat transfer to the bay floor, but then I have never looked for it. Next time we run it for a while, I will feel around. You can see in the pictures that the radiator blows out the curb side. It is sucking air from the driver's side, so maybe all that cross ventilation helps a bit. I have been thinking of finding some high heat rubber-type stuff to put under the muffler anyway.
CO detectors should be mandatory. Not only to monitor possible CO from your generator, but if you are downwind of another RV running a generator (especially without a vertical stack) with your windows open.
I saw this happen several years ago 1 dead and 1 with permanent brain damage. Jack
Jack,
Where is the best place to install a carbon monoxide detector?
I do have one, just need to put in the correct location.
Paul
With in about 1' of the ceiling. CO is lighter than air and will tend to rise. On the other hand, LP detectors need to be installed near the floor as LP s heavier than air. Jack
I installed a Kidde CO sensor on our last trip. I contacted the company about to height to install it. They said that CO mixes with the air, so it did not matter. The only recommendation was that it be at least 6 inches from the ceiling or the floor so that it will not be where air stagnates. You might want to call the manufacturer of the device you bought since you would want to sue them if it kills you.
I'm really confused on where to put CO detectors. I thought CO was low to the ground so I put a CO detector in the basement and near the gas fireplace. I have 8 CO detectors in my house, six of which are combo smoke/CO detectors. All 8 of the CO detectors are hardwired together so any one going off will sound alerts on all of them.
Overkill I know.
"It is important to install the detector in accordance with the manufacturer's instructions. CO detectors can be placed near the ceiling or near the floor as CO is very close to the same density as air"
From Wiki - HTH
P.S. - You want the CO detector in all living areas especially bedrooms - FWIW
HOw about at the same height that you or you family will be breathing? Maybe the height of your pillow.
Quote from: H3Jim on August 18, 2008, 01:13:32 PM
How about at the same height that you or you family will be breathing? Maybe the height of your pillow.
I would think you would want to know before it go to where you might breath it if possible.
I guess the makers of this stuff (pipes, tubes) want to be sure its bullet proof before they allow / suggest its use.
I followed the lead from Lin on the flexible exhaust hose. While its rated at 600 degree max, for continuous use, they limit it to 300 degrees or so. I called the manufacturer and they said they have had problems with folks that hae used it for generator applications, and did not want to help me any further.
I'm sure LIn has had no problems, and the way both he and Jack have the exhaust set up, seems like a great way to do it. Use solid pipe from the genset to a point where it goes vertical, then use a larger diameter pipe/ hose so the exhaust is mixed with cooler air, further dropping the temps.
An initial call to Dick Wright's office, they suggested that the exhaust temps would be around 1000 degrees from the 12k diesel genset I bought. That sounds way high, the exhaust temps from my v8 diesel truck are not that high under full load.
I'm trying to design for a pipe that goes up through the inside of my coach so I don't ever have to hang the vertical pipe. I'll work all day to aviod a 10 minute repetitive task. Hanging off the side of the coach, I'd be a lot less concerned about using materials that are not rated for the temp. going inside, however, I want to be very sure I get the specs and the design correct.
In using my genset, I have measured about 200 degrees, after the muffler, and a 45 minute run time. It was not under full load, and that could increase the temps significantly. And thats before any mixing of air in a vertical pipe.
Jim,
You have me here. I have not measured the temps at the exhaust. I will do that today. I have not yet used the system in a campground since power is usually available. Will your type of use require a generator stack often?
Did anyone use IR gun to report the real result? If so if you will, could you tell us what you find in temperature?
That would be interesting to learn what the real temperature is.
Thank you all.
FWIW
Sojourn for Christ, Jerry
H3Jim, email Hal St Clair his goes through the roof and has for years with no problem he can tell what he used
Lin,
I don't use the generator much, but its conceivable that I would run all three roof airs for hours on end, and the exhaust would get to the max temp. If I was running it outside and many have done, I'd be less concerned, but inside through the coach carries the risk of CO2, not to mention water leaks if something deforms enough, etc
The location of the muffler makes it more difficult to run the pipe to the side of the coach, as opposed to going up. The only way In can get to the side, is by having it be the lowest point in the bus underside. I'd hate to scrape it off going off road as I do sometimes.
Hal's is in the very back of the bus and does not really go through the interior
What do you guys do with the exhaust from the Pro-Heat ,Webasto and the Aqua Hot they smell and smoke as much as a generator and exhaust at 500 or 600 degrees and I don't recall ever seeing those with a stack
Quote from: luvrbus on August 19, 2008, 11:17:18 AM
What do you guys do with the exhaust from the Pro-Heat ,Webasto and the Aqua Hot they smell and smoke as much as a generator and exhaust at 500 or 600 degrees and I don't recall ever seeing those with a stack
We do not put a stack on our ProHeat, although I would like to. ProHeat's installation manual states no more than 5' of exhaust with minimal bends. I was concerned that the stack might create to much backpressure resulting in carbon build-up in the burner. Living and traveling in the SE, spending the winter in the southern half of Florida, our ProHeat rarely runs more than 20-30 minutes per hour when in use. We rarely need our ProHeat.
As fas the hot temperature, yes, you are absolutely correct. I have thought about putting a warning label on the side of the coach right above the exhaust (but of course, many would just have to touch it to see if it really was hot LOL)Jack
To answer Jerry's question
with a 7.5 Kohler gas generator pushing one AC, after 45 minutes and an ambient temp of about 100, the temps are:
1. center of exhaust manifold- 650
2. pipe entering the muffler (about 14 inches away)- 550
3. end of exhaust pipe (about 3 feet from other end of muffler)- 160
4. exhaust hose at 6 foot from connection to exhaust pipe- 130 (and still touchable)
Since the exhaust exiting the top of the hose/stack seems to be close to 150, it is possible the hose will continue to heat up a bit, but it is well within the specs of the hose.
Thank you Lin for your time and effort.
BTW...I corrected my confusing grammar of the previous IR post. Sorry.
About exhaust from Aqua and ProHeat would be added to this finding if any one is willing to.
Anyone else would like to share their finding of both Generator and heater exhaust temp?
Thanks
Sojourn for Christ, Jerry
I have shot the temp of our Proheat exhaust where it terminates about 2" beyond the side of the bus and only about 12-16" from the burner. Temp is 425-475 degrees. When camping and we may need ProHeat, I always check under the ProHeat exhaust for any tall grass or other flammable material. Jack
Jim,
I don't know your exact situation, so any suggestion may just be irrelevant, but I was wondering whether there might be a different option. For example, if you could use high heat braided hose and find a way to snake it to the side. Another thing I was thinking of would be to make the exhaust pipe wide and narrow to keep it high off the ground. For example, wouldn't a 1/2" x 7" tube have the same capacity as a 2" pipe? The surface area would actually be more, but maybe you have to allow for extra resistance.
Quote from: H3Jim on August 19, 2008, 10:49:33 AM
The location of the muffler makes it more difficult to run the pipe to the side of the coach, as opposed to going up. The only way In can get to the side, is by having it be the lowest point in the bus underside. I'd hate to scrape it off going off road as I do sometimes.
Jim,
If you brought the pipe straight out to the side, would it be close to the front or rear axle? The more centered between the axles, the more likely to hit something. That said, our 2" exhaust pipe runs lengthwise from the OEM AC condenser compartment to just in front of our drive axle (under all 3 baggage bays) and has not hit anything. If you enlarge the photo below of our ProHeat exhaust, you can see the generator exhaust pipe in the background. I don't know how "off road" you travel, but we frequently end up driving through cow pastures (some still have fresh cowpies)to a couple Bluegrass Festival sites. Jack
Jack,
It is hard to tell from your picture, but it looks like you have a bolt coming through with the nut on the low end of the top hat channel. The PO had done this with our generator and it began to cave the channel in. We had to modify it to return it to a good grip.
Quote from: Lin on August 20, 2008, 08:57:52 AM
Jack,
It is hard to tell from your picture, but it looks like you have a bolt coming through with the nut on the low end of the top hat channel. The PO had done this with our generator and it began to cave the channel in. We had to modify it to return it to a good grip.
Lin, good eye to notice that. Yes, that is one of 4 bolts that hold the ProHeat in place. The nut in the photo has Lock-Tite on it. Since the ProHeat is not very heavy, sits directly on the floor, does not vibrate, and all lines attaching to it (except the exhaust pipe through the floor) are flexible rubber with slack in them I was not to worried about it. Jack
When I ran my exhaust on my 13.5 k generator I first ran it under the bus into a flat muffler then about a 10 foot loop. I than ran the 1 1/2" pipe up thru the bus inside a 4" double wall vent pipe. The vet pipe never gets any warmer than the surrounding temp. By running it under the bus fist it cools it considerbly before it enters the bus. I have been driving the bus for 5 years and have never hit the exhast under the bus.
Wayne
The muffler is just in front of the duals, hanging from the bus frame via rubber mount and its about a foot higher than the bottom of the coach. right on that side, also just in front of the duals, I have a 4" dump. The dump hangs down below the bottom of the coach, so I didn't use glue on the elbow, I just clamped it. This way it can rip out, if I hit something and all I have to do is put another one in. I have ripped it out twice. It ended up being at a transition from pavement to dirt, and there was a little dropoff at the dirt.
The exhaust piipe would be smaller than the 4" of course, and could be mounted much more solidly. Although with the weight of the bus, I'm not sure anything could be made strong enough to keep from being ripped out.
Maybe I should Take RJ's driving course instead :o)
I talked to Dick Wright today about his ideas for an internal exhaust stack. He said that Marathon useed to make them internal, but really did them overkill. They used solid pipe all the way up, and used black pipe, connected directly to the exhaust, no mixing of air. Then they put the high temp wrap around the entire thing, then another thin wall pipe, then more wrap, then air space, then another thinwall pipe, then more wrap. There was airspace between one of the wraps and the outside pipe, and this airspace was open at the top and bottom. They used the solid pipe to reduce exhaust noise inside the coach. Then entire thing was about 12" in diameter. It had a custom vent on the top that looked like a pie pan with louvers and pipe coming out the middle. He said they finally stopped doing the internal runs due to liabilty concerns, although Dick did not know of any that ever burned up from the exhuast. He cautioned me that many wood products will catch on fire at 250 degrees or so, and this is not out of reach for a fully loaded genset on a hot day, running all day. Good point, but damn....
I think I may still run it up through the coach, but I really like the venturi idea that mixes cool air at the bottom along with exhaust gases as they rise up the pipe. I would rather over engineer it than under engineer it, but their solution sounds so overkill as to be ridiculous - to me anyway.
Jim,
A suggestion, if I can explain this. Make a pipe like I use, only using 3" exhaust pipe (one piece/no joints) instead of PVC pipe, with the short piece of exhaust pipe centered in the lower end to get the cooling/dilution effect. Wrap this with heat wrap (although I have never had any spot on my PVC pipe so hot that I could not hold my hand on it). Then install a one piece 6 or 7" exhaust pipe down through the bus, sealed at the roof and at the baggage floor. This pipe would be open all the way from the roof through the baggage compartment. This pipe cound also be wrapped for heat and sound insulation. Insert the 3" pipe inside the 6/7" pipe using stand-offs at the top and bottom to keep it centered. Let the 3" pipe stick up a few inches above the bus roof. Add a cover at the top to prevent rain from getting down in the exhaust pipe.
I saw a 1 piece vertical stack, that was a snup fit on the exhaust pipe, with no water drain at the bottom. After a hard rain, he started the diesel generator and spent the next several hours cleaning all the carbon mess of the side of his bus. Jack
I made an exhaust stack for Dad's motorhome tonight.
First attempt was 2" aluminized exhaust pipe from the local muffler shop & a long radius sweep elbow (EMT?) slipped over the generator exhaust. Dang thing was heavy. :( We welded a hook on the top to fit into a bracket added at the roof line. This pulls in air at the bottom, but not enough & as a result, the stack temp was over 250F.
Plan B:
Use 2 down spouts, a 2x3 inside a 3x4. Outside temps never got over 110F. ;D
But the dadgum thing made more noise than was tolerable outside the coach. :(
Looks like I'll be trying some more things as time allows. . . .
Re. detector placement;
If I might offer a suggestion as a former fire investigator. I think you will find this suggestion is consistent with the directives found in U.L. listings and National Fire Protection Association guidelines. Using smoke detectors as the example, what the instructions advise in general terms, is that the detector can be placed on the ceiling, but should be spaced a minimum of about a hand width from the wall. If the detector is secured to a wall, it should bw spaced about a hand width, or the width of your palm, from the ceiling. The reason for the spacing is that there is a dead air space near the intersection of the ceiling and wall, where the smoke cannot effectively displace the air. As a result, the smoke detector would have a delayed alarm time. If the detector is placed where smoke can naturally drift to it without having to be forced into a tight corner, or being influenced by air flow from a duct that supplies fresh air from somewhere in the coach, then you will have the earliest alarm possible. I hope that helps. Also, there is nothing wrong with doubling up on detectors. The idea is to follow the manufacturers guidelines and to avoid false alarms from cooking or steam (depending on the type of detector). Alarm devices need to be trustworthy. False alarms from misplaced or inappropriate detectors lessens credibility, resulting in batteries being removed. As a result, you're left without this important protection. Remember, we're not talking about weiner roast smoke here; the synthetic materials in our homes and buses will kill you before it will wake you up! The names of the gases produced in a home or bus fire have an alphabet in their names. I know I have gone off on somewhat of a tangent here when the original discussion was concerned with CO detectors, but I feel strongly about the info here, and the same principal applies to any detector; follow the instructions carefully. May we all stay safe!
Dennis