| Author | Message | ||
| Buddy Tennison (Buddyten)
Registered Member Username: Buddyten Post Number: 35 Registered: 7-2005 Posted From: 207.68.234.24 Rating: N/A |
Hey Guys: It's me again with another question. We have two Dometic "Brisk Air" 13.5 BTU roof tops on our Eagle. For the most part, they do a pretty good job except for those 95+/high humitidity days, and we want to add another. Our bus is used for a touring coach for our gospel quartet. It is divided up with a 14' long front lounge, a bunk and closet area, and a rear lounge. The bunk and rear lounge/dressing area are about 9' long each. Since there is a door between the front lounge and bunk area, we can close it off, and the rear unit adequately cools the bunk/rear lounge. We have the unit in the front lounge installed about 6' behind the escape hatch opening, and are thinking we might want to install another unit in the hatch opening to assist with driver cooling, as well as additional cooling in the front lounge. Are we on the right page with that? We have a 7000 Onan Marquis Generator (good genset by the way). Will the generator handle the 3 units OK? From what I have read in past posts, the critical factor is actually start up of the units, and not their continual running. Since this is a tour bus, and not a motorcoach, we have little else on the genset except for TV, Stereo, a few lights, a coffee maker and a microwave. Realize that we would have to shut one unit off to use coffeemaker or microwave. Are we thinking correctly here? Any suggestions to do things better? Also, yesterday, we had pulled off the interior shrouds of the AC units to do some cleaning and servicing. We turned the unit(s) on with the shrouds off, and the airflow was very much increased and the cooling capability was very much better. Our shrouds, naturally, have an opening for return air and another for supply air. The supply air side has a "vent opening" in the front and one in the back. Is there some modification that can be done to the shrouds, etc that will yield more air flow? Any suggestions. We have found that if we run a couple small oscillating fans (just to "stir the air about"), the cooling efficiency is better. We just sit them on the cabinet areas. Is there some type of fan(s) or air movers that we could install permanently and out of sight (possibly under our built in sofas) that would be more efficient? Any thoughts and suggestions to these questions would be greatly appreciated. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 236 Registered: 8-2006 Posted From: 207.231.81.129 Rating: |
Buddy, Sorry to rain on your campfire, but 7KW won't handle 3 roof airs. A 7KW rated generator, on gasoline at sea level will produce 58 amps, which sounds like enough for 3 X 15 = 45. Running on propane decreases the output, as does a rise in elevation. If your set is diesel fueled, maybe, but I wouldn't count on it. The standard rules require twice the running load to start, and if you had two running, which would be approximately 30 amps, you would need 30 more to start the 3rd unit, and you are a couple short, under optimal conditions. As soon as you add an amp or two for fans and lights, or a converter, etc. I feel you will have trouble. George | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 455 Registered: 7-2006 Posted From: 66.217.106.113 Rating: |
You can run two (of three) air conditioners on only 20/30 amps of park power (or a 4 KW generator), using a Pulse-AirŪ device. The third unit can run along by itself, as if you only were using your original two! http://www.campingworld.com/browse/skus/index.cfm?deptID=3&subOf=166,16&skunum=9320 Anything's possible, when you think out of the box.... BTW... Those shrouds have foam rubber strips inside, that keep the intake from the exhaust sides of the unit. If they're missing (or you remove a shroud), the unit will not operate properly. Ice will form eventually, and the unit will have to be turned off (to defrost), before it'll work again. Have fun! | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 68 Registered: 1-2007 Posted From: 65.61.96.82 Rating: N/A |
Buddy, An amp probe comes in very handy to see what things are actually using. With it you can measure what each device is using plus total current. Try to find one to borrow if you can. WARNING Redneck load test follows. You may have every thing you need to try a load test. See if a combination of the stuff you have will add up to about 1750 watts or 14.5 amps (read the id plates). Start one of the airs and some combination of the coffee maker and the microwave, ect that add up to about 1750 watts, then try to start the second air. If it starts and does not overload the genset you might make it. Monitor voltage for sure and amps if you can. The three airs are rated to pull 43.5 amps, 14.5 each. That gives you a cushion of about 15 amps or about a 75% load on the genset. Might handle starting loads, might not. Might run at that load for extended periods, might not. Depends on how everything is preforming. Wiring must also be up to snuff to prevent unwanted smoke. There is a gadget that alternate between airs to run two on a small genset. Maybe someone will know more about it. Have you cleaned out the coils on the condenser under the covers up on the roof? If you are close to making it with the two airs, maybe working on the insulation, windows (tint), roof color, ect might make the difference too. If the roof is something other that white it can make a big diff. Good luck Don 4107 | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 238 Registered: 8-2006 Posted From: 207.231.81.129 Rating: |
Buddy, Here's my second set of comments: 1. I like Don's post for two reasons. "Might run at that load for extended periods, might not." I should have said it that way in my first post, instead of "I feel you will have trouble." Second, "There is a gadget that ALTERNATES between..." Don accurately describes a Pulse Air device, which SWITCHES BETWEEN two roof airs. 2. John leaves out the second sentence of the Pulse Air ad, which reads "Alternates between two roof airs, cools two areas, saves power," etc. Well, it must be made clear that all this unit does is turn on one unit at a time, and switch back and forth between the two units. It does not save ONE WATT of power, the only reason it is not an outright lie, is that two units running at the same time would use more power than one! It should also say 'partially cools two areas,' because one of the two compressors is always OFF! This is what happens when you spend too much time "thinking outside of the box," and not enough time paying attention to reality. George | ||
| Spencer Champion (Spencer)
Registered Member Username: Spencer Post Number: 17 Registered: 4-2006 Posted From: 68.219.30.204 Rating: N/A |
The suggestion of checking on the actual number of amps you are pulling is a good one. You might also think of a smaller A/C unit. Smaller might be just what you need to get past the heat wave. Insulation, tinting, white reflective roof are all part of the solution. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 412 Registered: 11-2005 Posted From: 63.97.117.13 Rating: N/A |
I had the same problem with my 4104. I cut a rectangular hole in the bottom of the shroud, lined the hole with rigid foam so the air would go straight down, and installed a grate for a house floor vent. Now the air goes straight down to the floor where it is needed and is very powerful. The four seated passengers get a bit too cool sometimes. Last year my granddaughters suffered from the heat, this year one used a blanket! An amazing difference. I have a fan that blows the air from the AC to the driver which keeps me cool. This is not my original idea, I got it from an RV magazine-simple but effective. | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 75 Registered: 5-2007 Posted From: 64.40.223.242 Rating: N/A |
Our coach came with the same idea as Gus, it works really well. As I have three roof airs, the center is the coolest. I thought it looked hokey (spelling?), but it works. Good idea on lining it with rigid foam to direct the airflow. I need to do that. Paul | ||
| James Robinson (Jjrbus)
Registered Member Username: Jjrbus Post Number: 94 Registered: 12-2000 Posted From: 68.244.254.26 Rating: N/A |
This year I had the chance to inspect an AC that was replaced becuse it was "weak" I took the exterior shroud off and found that the condenser coil was at least %60 blocked with crud!!! I'm not going to to tell you what to do, but befor redoing everything, I'd try removing the exterior shrounds and what ever else you need to to get to the condenser coil and evaporator coil. Give them a good cleaning. Also check that the drains for water are clear. Has the inside filter, been cleaned/replaced? Is it the right filter? Is there a filter, if not you can bet the coils are dirty. Let us know what you find, HTH Jim | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 457 Registered: 7-2006 Posted From: 66.217.101.188 Rating: |
For nearly all owners of 30 amp RVs, the problem of running both AC units while connected to the shoreline, was a problem. The "Pulse Air" unit satisfied many campers for many years. Yes, it alternates the power between the two, but it does so automatically. The RVer doesn't have to get up, flip the transfer switch, and turn one AC off and the other on manually. And as long as the genset can run two AC units, using that Pulse Air unit can allow three AC units to run, providing cool air to the entire rig. (Message edited by john_mc9 on August 02, 2007) | ||
| Nick Badame Refrigeration Co. (Dnick85)
Registered Member Username: Dnick85 Post Number: 166 Registered: 2-2006 Posted From: 70.208.167.146 Rating: N/A |
Hi Buddy, I'll keep this simple... I don't know how old your roofers are but, if they are in the 10 year range, they have lost alot of efficency due to wear. If you were to upgrade, use two 15,000 btu units. There is no reason why 2 roofers won't cool your entire bus unless you want to use them while driveing.. Thats another topic..Lol Good Luck Nick- | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 97 Registered: 10-2005 Posted From: 70.56.157.202 Rating: N/A |
Nick, what is the issue using them while driving?? | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 98 Registered: 10-2005 Posted From: 70.56.157.202 Rating: N/A |
I have 2 15k btu roof units connected to a Honda ES6500 Genset converted to propane, the genset is not running properly for some reason and I am working on it after driving 400 miles in 100F temps with one unit barely blowing any air, miserable. I found that the genset was producing 115vac at only 50hz, not enough frequency to run the compressor properly. I have been working to get the RPM up enough to yield the proper 60hz but seem to have some vacuum leaks in the propane side of the fuel system. While the 6500kw unit should be able to start and run both AC units the best I have gotten so far is getting it to run one properly whihc will likely be enough to get us home without heat stroke. I am about ready to give up on the Propane conversion and restore the unit to gasoline use. I feel that I may have made a poor choice in installing the genset rather than the inverter, had the inverter been installed even with 2 8D batteries and a 200 amp connection to the alt I feel I would have been able to run the AC's without issue as long as the coach was running, whihc is the only time I have had need to the AC's, I would nto have been dealing with a generator running in the bay, a cooling fan, propane canisters, etc, etc. Live and learn. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 689 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
How big is your propane tank? If it is too small, maybe you are getting a pressure drop after a while as the gas gets cold. My brother installed a propane generator in his coach several years ago, and had trouble with it at first. After getting the propane issues resolved, he has had many years of satisfactory use. | ||
| Nick Badame Refrigeration Co. (Dnick85)
Registered Member Username: Dnick85 Post Number: 167 Registered: 2-2006 Posted From: 70.208.165.168 Rating: N/A |
Hi Christopher, I hope you get the gen set problems sorted out. That 50 hz's can burn the windings in the A/C compressor. You mentioned that it's 100deg's where you are. Last year, driving to Columbus OH, it was 103 deg's and driving into the afternoon sun.. My condencer fan burned up just before the trip and I had to suffer until Jack Conrad shipped me another. Today, driving back from central PA, 97 deg. and I had to keep switching the OTR A/C off because it works too well. Oh, My new jakes are working thanks to Keith Crawford. Still have some bugs to work out but, I like the extra braking power. Nick- | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 240 Registered: 8-2006 Posted From: 207.231.81.129 Rating: |
Chris, You can't have a vacuum leak on a propane system, because its all under pressure up to the carburetor! (If it was leaking, you would have smelled it if it didn't catch fire?) Sorry, now lets see if we can fix it! John W makes the first point to ponder, immediately above. The pressure in a propane tank varies directly according to its temperature. During use, propane evaporates off the top of the liquid in the tank, cooling it. If the temp drops below the pressure level the regulator needs to function properly, the engine will starve for fuel. Your telling us that you are only getting 50hz, and 115v, is 'yelling' under horsepower. The indicator to this being the problem is if the gen will run properly for a few minutes, then start to slow down. The solution, if this is the problem, is a larger tank, or manifolding the small ones together. Next question, Is the generator connected to a "first stage" regulator, I hope? 10psi output instead of 11 inches WC. Next thought, propane has only 94,600 BTU/gal, compared to 144,000 for gas or diesel, with a corresponding reduction in horsepower. All gensets are rated on gas or diesel, you have to do the lpg derate... Is the gen getting "cool" fresh air? Hot air, and recirculated exhaust will greatly reduce the engine's power. A 6.5, even on propane, should run two roof airs. Please, write back, and tell us exactly how you are set up. HTH, a lot to think about, George | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 190 Registered: 7-2006 Posted From: 4.240.144.163 Rating: N/A |
Good post, George...helpful information and straight forward....and you are correct, a lot to chew on.  FWIW RCB '64 Crown Supercoach (HWC) | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 459 Registered: 7-2006 Posted From: 66.217.102.77 Rating: N/A |
http://mayberrys.com/honda/generator/models/em6000.htm | ||
| Chuck Newman (Chuck_newman)
Registered Member Username: Chuck_newman Post Number: 210 Registered: 1-2005 Posted From: 67.126.207.52 Rating: N/A |
George, I don't know the specs on the Honda ES6500, but all the generators we have from 10KW to 40KW run on 13"W.C., not 10 PSI. From my experience, it sounds like Chris is running the Honda with a single stage regulator on a tank with too small a surface area resulting in partial ice up within the regulator. | ||
| Chuck Newman (Chuck_newman)
Registered Member Username: Chuck_newman Post Number: 211 Registered: 1-2005 Posted From: 67.126.207.52 Rating: N/A |
Just read the ES6500 specs on the Honda site and was thinking what type of gasoline-to-lpg conversion does Chris have? Most engine "conversions" I've seen use liquid propane (drawn from the bottom of the tank) as opposed to a typical RV type lpg generator that uses vapor lpg (drawn from the top of the tank). | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 243 Registered: 8-2006 Posted From: 207.231.81.129 Rating: N/A |
"Honda ES65000 converted to propane" posted 8/3/07, 3:03pm "Model EM6000GP Propane Only Generator" posted 8/4/07, 703pm Congratulations, John! You have posted a link to an entirely different wattage AND model generator. Apparently you didn't read "that I am familiar with," either. This is equally a non-constructive post as yours on the 12 to 48 volt converter for a 24 volt bus! I would not have posted that here, except that you show owning an MC9, as does that poster, so you should have known what voltage his bus was, before making another non-constructive post. Now, please note the minimum tank size you have posted, along with the minimum pipe size, AND the 150,000 BTU/ hour minimum supply requirement, for a smaller generator. Dividing 150,000 by 94,600 will tell you the number of gallons per hour consumed, and the amount of heat that must be removed from the bay the generator is installed in. Since you have posted a link to a smaller and different generator, it is obvious that the supply requirements, and the heat output for the genset in question will be larger than those you have posted. By this post, I am defending my credibility, and suggesting putting the effort into a helpful post instead. You are welcome to correct me off-board, as my e-mail isn't hidden. George | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 461 Registered: 7-2006 Posted From: 66.217.105.125 Rating: N/A |
Re: "By this post, I am defending my credibility" Being the only "QUALIFIED" poster on the board must be a real bitch, ehh George? Maybe you oughta' change your "profile"? You don't seem to actually read anything I post, only give criticism, using out of context quotes.... Too bad! Chuck's comments were right on target regarding Chris' genset. And the pressure is WC, not psi. I provided a fairly easy to understand link on the "other" thread, that should provide more than enough information about any/all propane conversion kits, and the installation of the same. There isn't much difference between the 6000 and 6500, by the way. Get a life, George..... There's plenty of "QUALIFIED" individuals out here. "Got ulcers?" (HAR) | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 416 Registered: 11-2005 Posted From: 63.97.117.25 Rating: N/A |
I have to agree with George, a lot of JMC9 posts seem to be just to add to total posts-shades of 2DG!! | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 462 Registered: 7-2006 Posted From: 66.217.105.125 Rating: N/A |
No hard feelings, Gus.... We all have our "favorites". | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 695 Registered: 10-2003 Posted From: 71.58.117.21 Rating: |
Looks like George, John, and Gus need to go out in the snow and have a writing contest. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 246 Registered: 8-2006 Posted From: 207.231.81.129 Rating: N/A |
John, The first sentences of your post of Aug. 2, 07 147am read: "You can run two (of three) air conditioners on only 20/30 amps of park power, (or a 4KW generator) using a Pulse Air Device. The third unit can run along by itself, as if you were only using your original two." I obviously didn't take anything out of context, that is your post, and it doesn't explain in any way that a Pulse Air ONLY RUNS ONE UNIT AT A TIME! Your post also, in its entirety: "Anything's possible, when you think out of the box..." Your recent post: "Some engineers can make anything work, some can't make anything work" Yesterday, you posted a link to an entirely different generator than the one in question, WITHOUT ONE WORD OF EXPLANATION OR HELP. On another topic, you recently posted a picture of a 12 to 48 volt converter, (for use in a 24 volt bus,) and YOU KNEW it was 24V, (as it is an MC9, same as yours,) which was exactly the same thing you did yesterday, posting a different link than what was being discussed. You know where you put those posts, and why! Now you snivel and make personal remarks? I've never made a personal remark to you, or anyone else on this board either, and I'm not going to start now. George | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 418 Registered: 11-2005 Posted From: 63.97.117.39 Rating: N/A |
john w, Yeah, you're probably correct but it is too hot here to work on the bus and my fuse is a bit short. George doesn't need my help anyway, he is explaining it very well!! There is a big difference between data and information. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 419 Registered: 11-2005 Posted From: 63.97.117.39 Rating: N/A |
Speaking of information, I forgot to explain that my whole first post was only about using the rooftops while underway. We hardly ever use the AC when parked but if we do we use the rear one which still has the original fore and aft outlets. A hole straight down through that one would probably make the bedroom/bath/kitchen area too cold. It is possible to use the included shutter in the house floor outlet and close off the straight down vent if desired. I was in a hurry and didn't want to take the time to do it so I just removed the shutter. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 464 Registered: 7-2006 Posted From: 66.217.101.150 Rating: N/A |
George - 1. The "Pulse Air" device allows two air conditioners to run on a 30 amp circuit.. The link I provided explains how. Using that device on one genset "leg" to power two of the three AC units will allow the third AC unit to remain powered by the genset's other "leg". Hence, you can have three AC units spreading cool air throughout the RV, using a genset capable of only normally being able to run two at a time. Yes, two will alternate automatically, but when one wants cool air distributed via three units, it will suffice nicely. 2. The Honda 6000 and the 6500 similar enough to indicate the fact that: A. It uses vapor, and B. Pressure is measured by water column. The posts to another thread, provides a link to gas to propane conversion kits, and explains in great detail, all the hows and why of conversion. And yes, as even you finally concluded, Chris appears to have a regulator or regulator setting problem. 3. The link I had posted on some "other thread" provides information regarding all types and models of DC to DC converters, DC to AC inverters, step-up, step-down, etc. The picture posted was the only one available; the link provides all the info needed. I posted it specifically, due to your comments to the poor soul looking for one, stating that a 24 to 48 converter was difficult to obtain. They aren't; that one link should be proof enough. The poster only wanted to know all options available to him, and I felt he oughta' at least be provided with the knowledge that options are indeed, available. I don't post to pee you off, bub. I post in an effort to offer options that may not be "mainstream". There are tons of ways to find a means to an end. Engineers and professors often overlook easier ways.. And more often, valuable solutions come from who we least expect. It would be appreciated if you refrained from discounting all those without a "proper license", as being "unQUALIFIED" to post suggestions. This is an open forum, like any other; you'll find guys and gals from all walks of life, each with a bit of knowledge that can add greatly to the overall knowledge available. You may not realize how condescending your posts sound to some other readers.... but trust me... "Life's experience" counts as much as a degree or license.. Perhaps more. Tolerance, George... It goes further than you think. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 466 Registered: 7-2006 Posted From: 66.217.102.52 Rating: N/A |
Mr. Roan?  howz dat? | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 248 Registered: 8-2006 Posted From: 207.231.81.129 Rating: N/A |
John, My posts are indeed condescending, as I put a lot of effort into explaining things clearly in terms everyone can understand. In your ugly post of Aug.5,07 and the ones immediately above, you call names which are offensive to many people on this board. It is also obvious to me, and everyone else here, that had you practiced what you now preach, we wouldn't be here. So, start now, and we won't be back! | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 696 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
John 9MC- from the looks of your signature... you need to be drinking more liquids. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 424 Registered: 11-2005 Posted From: 63.97.117.43 Rating: N/A |
The word for that mc9 post is, "Tacky". | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 470 Registered: 7-2006 Posted From: 66.217.103.119 Rating: N/A |
Tacky? I thought it'd be dry by now! Gus..... John R said: "Looks like George, John, and Gus need to go out in the snow and have a writing contest." I (without quite enough to drink), did my best to fulfill Mr. R's request. And I did it no-handed, I might add! </levity> Buddy - Did you get your original question answered to your satisfaction, or did we lose you somewhere? | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 249 Registered: 8-2006 Posted From: 207.231.81.129 Rating: N/A |
OOOH! I can't beleive I've gotten the chance to answer this one after a day and a half, I know how many people thought it though!!! THAT'S WHAT YOU DO WHEN IT'S TOO SHORT TO HANDLE! (Don't ever pick on somebody, and then give them an opportunity like this one! Gotcha!) | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 473 Registered: 7-2006 Posted From: 66.217.105.148 Rating: N/A |
Ouch, George!!! |
