We have 2 coleman basement units that are 2 tons each. Is one unit enough to make it plenty cool? We dont have any road airs. We have done overkill on all the insulations in the bus though. And we only have 3 windows, tinted in the bus. Also, if we installed the 2nd unit, would it need to be vented separately, or can it run through the same duct work at the same time. We are having a hard time getting everything to fit in the basement. We definetly want enough air to stay plenty cool, especially when going down the road. We also want to have as much water and holding capacity as possible. Right now we have allowed for 100 gallons of fresh water, and 100 gallons of gray, black tank. Using it the way we do, with 4 people, we could use more, if possible. But, working and moving a lot, in most cases, we have the opportunity to dump about once a week. We are putting in a washer and dryer,inside the bus, which will be used occasionally. But, to make a long story short, we are running out of compartment room. We have to keep one compartment availiable for tools. We are a little concerned too that if one air unit breaks down, it would be nice to have a back up. Any advice from those that have gone through this?
I would definitely want two. If you find yourselves in Arizona or Florida, one will not get it, no matter how well insulated you are. When I had my 4104, I used two Dometic basement units, both connected to the same distribution system with a two stage thermostat. When one would do the job, that's all that ran, when it needed two, the second would kick in. I also installed a double throw switch in the control circuit so that I could change which unit had priority. I would switch them once a month or so, to keep the wear even on them.
Ruthi,
I am hoping Nick will confirm my suspicions but I have two colemans that take up almost my entire 2nd bay and I have certainly felt that having both running on high has not been adequate at times. If you are parked in the open with no shade available and it gets above 80-90 degrees I would say you will struggle with both running on high. You are doing one of the best things you can do by insulating your ductwork mine is not insulated and only Nick or someone who has been able to see the results firsthand will be able to verify what kind of help insulating will be, but insulating certainly can't hurt.
So my vote is install and use them both...
As far as your capacities go. There are too many variables for anyone to guess better than you. Do you take "army" showers?
Meaning do you get your hair wet, shut the water off, shampoo, turn the water back on to rinse etc.? or do you just hop in and take a shower? Do you wash alot of dishes or use paper plates? Those kind of questions lead to vastly different consumption levels.
I know it's hard giving up the bay space for the 2 colemans but it is worth it in my opinion. The builder of our conversion decided to cut the bus down the middle lengthwise as far as AC, electrical, etc. which means my colemans are on opposite sides of the bus. If Nick or someone has devised a better plan maybe you can get away with using half of a bay for the colemans. Just a thought. Good luck and I hope this is helpful to you.
Rick
Ruthi,
We had a washer dryer rig in our last bus and we used it... ONCE!
The darn things only hold about one pair of pants in them and man did ours use water and electric. In hindsight , we would have used that space for something else and found local laundromats. Maybe the design has changed but the whole concept seemed a bit flawed amd limited by the size of the washer and dryer.
They are also difficult to winterize well. We really struggled to get every last drop of water out of ours and we obviously weren't going to use RV antifreeze in our washer. So, it froze with a small amount of water and broke a bunch of stuff internally.
Rick
Rick, how big are your units? Ours are 24k btus. I know we dont want to be hot. We had an airconditioning man come out to give us advice. He said the 2 ton units are what they install in some houses, and 1 was more than enough. I knew I had heard of those on the boards that said they had two installed. As far as water capacity, we take one minute showers, use paper plates, and conserve as much as possible. We have a 60 gallon tank right now, and it will usually last around 5 days for 4 of us using it sparingly.
Rick, we have a front load washer and dryer to install. We work on the road most of the year, so it will get a lot of use, and it stays running or plugged in year round. I hate having to use the washers at the truck stops, so, when we go there to dump and fill, we can use our own set, then dump and fill again. Every now and then, we are in areas where it is hard to find a flyin J, and we have to stretch the water a little farther. Camp grounds are hard for us to dump, because of the size of bus, and trailer we tow.
Len, what size were your units? What size ducting did you use? We are getting so much conflicting advice from so many different professionals, it is getting crazy. Dont want to have to do this twice.
If you run both units at the same time through the same ductwork you'll need to basically double the size of the ductwork.
If you don't have enough airflow the units can ice up and quit producing any cold air.
Ruthi,
I had two 15k in a 35' bus which was not all that well insulated. They struggled on a hot day, particularly when underway.
Some years ago, Consumer Reports had a section where you could calculate the size of a room air conditioner. When I did the calculations for a bus, (all four sides of the "room" exposed, no attic, window area etc) the numbers were high (don't remember exactly). Throw in a steady 70 mph wind and they go up to very high.
I can cool my 1500 square foot house in Florida with three tons, but it would be marginal for a 320 square foot bus.
Len
Quote from: belfert on November 27, 2009, 07:37:25 AM
If you run both units at the same time through the same ductwork you'll need to basically double the size of the ductwork.
If you don't have enough airflow the units can ice up and quit producing any cold air.
Yes, absolutely, you have to size the ducts for both units. I should have thought to mention that.
Hmmmm, well, right now, we have 52 inch total for the duct which is 10 inches more than needed, so we would have to increase it to 32 more inches to have them flow together? Or, make a separate ductwork for the 2nd unit. Does increasing the amount of vents, and, or having more vents as well as larger vents cut down on the amount needed?
I have three 13,500btu Coleman roof airs. I also have 2.25" of sprayed insulation, single pane lightly gray tinted windows. Driving in 108 degree weather (the hottest I've been in), two of the roof airs will do the job. I have tried all three running, then my wife has to put on a sweater. I don't believe you'd need two of the 2 ton units-over kill. I would install one and give it a season of work. If you feel you need more, Duotherm makes the truckers A/C's which is a self contained unit that can be either mounted in the bay or inside at the base of a cabinet. They make them in 7, 11 & 14,000 btu/hr. Personally, I'm using two of the 15,000btu Penquins that are made for ducting with remote thermostats, mounting them in the basement of my truck. If they don't cool enough, I will also add the trucker A/C to supplement them. I'm using Penquins basement mounted since they cost half of what a basement unit does, just duct the in and out air, and the condenser hot air can be ducted also since the Penquin uses a squirrel cage blower that can easily be ducted. Then if repair is needed, anyone knows how to work on roof top units, or they can easily be replaced, as compared to a basement unit. As of the first of the year (when I'll be buying my Penquins) the freon is being changed from R22 to more environmentally friendly R404A (I believe). Good Luck,TomC
Quote from: ruthi on November 27, 2009, 05:24:56 AM
We have 2 coleman basement units that are 2 tons each. Is one unit enough to make it plenty cool? We dont have any road airs. We have done overkill on all the insulations in the bus though. And we only have 3 windows, tinted in the bus. Also, if we installed the 2nd unit, would it need to be vented separately, or can it run through the same duct work at the same time. We are having a hard time getting everything to fit in the basement.
Hi Ruthi,
First, you say you have the 2 ton coleman basement units. If so, they are 26, 000 btu's each and each have 2 compressors in them that
require [2] 120v power legs/curcuits each to operate. My first question is, do you have enough power to operate both basement units together
off your generator while rolling down the road?
In my coach, I have two 15,000 btu single HP units [stacked] which add up to 2 1/2 tons [30,000btus] of air. Not 26,000 btu's like a duel coleman.
Even my house A/C units are not enough A/C for over the road use.. Thats why some of us choose to leave our 11 ton bus OTR air system operational.
Now, if you have enough power to run 2 duel coleman units for road use, your next issue is duct design and proper insulation to have a system
that will proform where you need it. Obviously, while traveling down the road, your biggest heat load/loss is the front windshield and the air leaks
around your entrance door, windows, and the front dash area which none are insulated or very little... So, you will have to incorperate a way to direct
most of your CFM's to the front somehow and be able to redirect it back to the rest of your coach when you are parked.
Not trying to hamper your plans at all. I'm just trying to give you the the proper ways to accomplish what you need for cooling underway..
Good Luck
Nick-
So, right now we have a powertech 12 kw gen. And you said you have 30000 btu. Are you able to keep yours cool with just that running? If it is necesserry to have them both we will, just didnt know if it would be needed. Obviously, ours would be a little less with only one 2 ton. If you get a chance, can you please call and talk to hubby? I think you have the number from other post. Thanks for your time.
Nick is the professional....For what its worth we have 2 14700 in the basement ,one ducted to the drivers area,one ducted to the kitchen area;also one 10000 in the bed room area...We are total electric with a 7.5 kohler gen set... all run OK and other appliances also.on a 100 degree day they will hold 72 degrees on the road..we also have a very small ceiling fan mounted above the driver to pull the heat off the ceiling(helps a bunch)good luck!
May I butt into this conversation for some cool advice?
To provide A/C to a complete coach, am I hearing you all saying that 4 ton may not be enough?
I have enough power (50Kw, diesel) to run more, so before I decide which units to purchase, and I want them to go underneath, talk to me about how much A/C I will need.
I want to set up an engine driven A/C system for the driver, when travelling alone, or everyone sitting up front. Then I was going to add two basement systems (front & rear) for the balance of the coach.
I am using hot water heat exchanger to heat domestic water (while driving) and for the heating system.
The factory A/C unit is toast (whole wheat), but I do have the components of that system. Should I consider reworking that system for while I am on the road?
This is not my forst conversion, but it is my most important, as it will be used to travel all over the country by people who will want it to be perfect.
Thank you for your advice.
Quote from: PCC on November 27, 2009, 04:27:08 PM
I have enough power (50Kw, diesel) to run more, so before I decide which units to purchase, and I want them to go underneath, talk to
I'm curious why you have a 50KW generator? What do you use that much power for?
Quote from: belfert on November 27, 2009, 06:24:35 PM
Quote from: PCC on November 27, 2009, 04:27:08 PM
I have enough power (50Kw, diesel) to run more, so before I decide which units to purchase, and I want them to go underneath, talk to
I'm curious why you have a 50KW generator? What do you use that much power for?
Sound system :o? 8) 8) 8)
God bless,
John
Ruthi,
We have five 15K roof top, ac's. That is a total of 75K cooling...
I don't think that you would regret having the extra one, other then the space issue. Not to mention, if one goes out, then you have a back up. We could have gone with fewer roof airs, but we figured, why not? There is a reason entertainers have so many. The reason is, redundancy. One goes out, not a problem. Two goes out, no biggie....
BTW, we only carry 80 gallons of fresh, right now. We are going to have another tank made, that will hold 100. We have a total of 300 gallons gray and black (175 gray, 125 black). It has worked very well, so far.
I am not sure if you all have plumbed for this, but you might want to plumb, two water pumps. That way, if one goes out, you have a backup...
Also, what are you doing for a water heater?
FWIW
God bless,
John
I think we will be alright in the water depart, as it a lot more than we had in the old bus. We are going to have the small 10 gallon hot water. We thought about doing the hot water on demand system to save room. But, we had one of those put in the house, and it took 3 replacements of parts and a new one to get it working right. Now, it works awesome, but we dont want to go through the hassle of that again. We have never had an issue with running out of hot water. I guess we are going to go ahead and install both of the air units. Dont want to regret not getting enough air. We originally wanted to have a spare air, and a spare gen set, so, I guess this will work out. We modified the front of the bus and bumper, so that a gen can go under the front where the spare use to go. To get to it, it slides out forward. This past yr, we had too many problems, so we are trying to cover those basis. Electricity and air are very important. We are only going to have 3 of the original windows in the whole bus, so, no windows to open. We had RV windows put in the gmc, and we hate the leaks and noise that creates. We run the gen. round the clock anyways. We ran ducting in the ceiling for the first air conditioner, so, looks like we will have to run some in the floor for the second. We are trying to keep as much bay space as possible as we need the space for the tools we carry for work. We have a large tool wagon, ladders, paste machine, etc. Sure going to miss the bay space in the gmc. ::)
BTW John, we have only had one water pump to go out, and that was yrs ago. I can sure deal with that a lot easier than being without air or elec. ;D
To answer the question about the 50Kw diesel generator, add to that John's comment about a sound system (!!), this vehicle is being built to travel as a venue/stage for live concerts and missionary work, so we will need to be able to power a large sound system, lights, and a few more toys that I plan to add to this vehicle for its mission. It is being done as a gift to a number of youth groups who have a desire to get outside the four walls of the building where the people they want to see spend almost all their time.
So this vehicle is being built with the financial assistance of people who see the goal for its conversion (pun intended), but there is another, more direct reason for the size of this generator - it was a steal at under $10,000, and it does fit into the bay directly behind the fuel tank, making the connections fairly simply, other than the exhaust, which I have to run half the length of the coach, and disconnectable, so that I can pull the unit ouot for servicing, and to run it away from the coach, should that ever be needed.
Back though to my advice request - Am I reading that 4 ton A/C may not be enough? Before I place the funds I have budgetted into a system that will prove insufficient, I really need to know.
I hope you all will give me some sound advice on this because I do not want to make a mistake.
Thank you all,
Keith
The typical factory air on a bus is about 12 tons. Everyone says you don't need all that because of no passengers. I found a number of about 400 btu per hour for a seated person, and times 49 passengers, that's only about 1.6 tons for the passenger load, leaving about 10 tons for everything else.
Just something to think about.
Quote from: Len Silva on November 28, 2009, 11:47:47 AM
The typical factory air on a bus is about 12 tons. Everyone says you don't need all that because of no passengers. I found a number of about 400 btu per hour for a seated person, and times 49 passengers, that's only about 1.6 tons for the passenger load, leaving about 10 tons for everything else.
Just something to think about.
Hi Len,
The rest is for the heat load through the windshield and all the air leaks... Lol But it sure works better then anything alse!
So, Nick and Len, are you recommending that I rework the existing A/C (factory) system as my first line of cool, with the basement A/C systems for when not driving?
That seems to me to become redundant, because if I put enough tonage into the generator powered systems, I can use about the same amount of fuel (maybe a bit more) and have the generator powered systems working even while driving. That would also increase my available driving power for hills, and other driving situations that I may encounter while travelling.
Am I missing something important with my reasoning??
Hi PCC,
Everybody is different.. I happen to like it cold in my coach while driving. Some only need a little coolness hitting them..
Redundency is a very good thing in a bus conversion.. If your biggest worry is losing HP on hills, then do as I do and simply
switch the A/C off for the climb. You wont cool down that much with 11 tons blowing into your bus. Most of the time,
my OTR A/C runs for 5 mins and then off for 10 mins. Otherwise you'll frost the windows up. Lol..
If something should happen to your house A/C or generator, hay, you still would have OTR air. And vise-versa.
Good Luck
Nick-
Good points, Mr. Nick. I had not considered that situation, so now to think about reworking the factory A/C. That is a scary situation; you have just given me a project I am not sure that I am truly excited about !!!!!
Having removed the front heat/cool/fan box from under the coach, and used the space (presuming I would go for gen-powered, are there options for a simple replacement set of coils to add that is A/C only. I can arrange the air distribution, so how would you suggest I decide what I need to distribute the cooled air.
Can a horizontally-mounted set of coils be mounted vertically? If so, I know how to re-install that unit, which is 54" X 36" X 10". I can remount that unit up high inside the coach above a doorway (duck your head,please), and duct it along the ceiling, or by hiding it behind a cabinet in the divider between rooms, if I can rotate it to vertical.
I can (another option) reduct the rear unit to send air to the front area in the coach, but I am reducing the system capacity, so what else has to change, if that is a possible option?? Do I remove one of the radiators from the system to balance things?? Will the same compressor still do the job??
Now I am full of questions - my ignorance is showing, but then how does one learn without asking the questions?
Hopefully, I am not upsetting anyone by having to talk this through?
Thank you all.
Keith
PCC,
IF the OTR air, isn't an option, I might have another option for you.
You might just want to go out, and get SIX (yes 6), roof top ac units (5 would do just great too). Get the 15K, ones, and set them up there. VIOLA, problem solved....
But again, that is only IF you can't do the OTR air.
We couldn't get ours going, after spending lots of $$$ on it, so we just have the generator, and roof airs...
FWIW
Oh, yes, you might get more publicity on this thread, if you got one of the mods to move it to a new thread...I think it is fine here, just thought you might want others to see it too...
God bless,
John
On top is not an option, because I am already almost 13 feet high, and I am concerned about clearance when arriving at buildings with a covered entry, so I must stay underneath.
So is there a high power A/C unit compact enough to go under the bus? I like cold, personally, so I have to do something, now that my plans have been stopped and altered by this discussion.
I will find a way to get the unit installed, if I find something that will work.
Keith
Keith, just be glad you plans are stopped now...you can get help BEFORE wasting a lot of time!
Jack
I know what you mean about height, Keith. There are very few church overhangs, that we can pull under (except for the lager to mega churches, all of those are usually fine). That just means, toting farther ;D.
Hope you get it figured out.
God bless,
John
Thank you John, but I am also thinking about trees that are trimmed for semi-trailers that do not care about branches hitting the corners, and dragging across the roof.
Leaves me no choice but to find a way to set up a system under the floor. I can be very creative, if I know what I am able to do with the equipment that came with the coach, or if i can find a system that will do the job powewred by the generator.
Thanks again
Keith
Quote from: PCC on November 28, 2009, 08:44:28 PM
Good points, Mr. Nick. I had not considered that situation, so now to think about reworking the factory A/C. That is a scary situation; you have just given me a project I am not sure that I am truly excited about !!!!!
Having removed the front heat/cool/fan box from under the coach, and used the space (presuming I would go for gen-powered, are there options for a simple replacement set of coils to add that is A/C only. I can arrange the air distribution, so how would you suggest I decide what I need to distribute the cooled air.
Can a horizontally-mounted set of coils be mounted vertically? If so, I know how to re-install that unit, which is 54" X 36" X 10". I can remount that unit up high inside the coach above a doorway (duck your head,please), and duct it along the ceiling, or by hiding it behind a cabinet in the divider between rooms, if I can rotate it to vertical.
I can (another option) reduct the rear unit to send air to the front area in the coach, but I am reducing the system capacity, so what else has to change, if that is a possible option?? Do I remove one of the radiators from the system to balance things?? Will the same compressor still do the job??
Now I am full of questions - my ignorance is showing, but then how does one learn without asking the questions?
Hopefully, I am not upsetting anyone by having to talk this through?
Thank you all.
Keith
PCC,
If you can't reinstall the evaporator in it's compartment, resizing the coils may be a big challange to do $$ wise..
Another idea would be to install a Red Dot A/C system. One for the dash and 1 for the midship area.
Do a search on Red Dot, they have many different options and a phone call would get someone to design it for ya..
Good Luck
Nick-
Quote from: PCC on November 28, 2009, 09:58:33 PM
Thank you John, but I am also thinking about trees that are trimmed for semi-trailers that do not care about branches hitting the corners, and dragging across the roof.
Leaves me no choice but to find a way to set up a system under the floor. I can be very creative, if I know what I am able to do with the equipment that came with the coach, or if i can find a system that will do the job powered by the generator.
Thanks again
Keith
Keith,
You hit the nail right on the head, about trees. Those are our biggest enemy. You wouldn't believe where we have been, though :o ;D. Seriously! We do carry an electric pole chainsaw, that we can trim branches, if necessary. We are right at 13 tall (with the roof airs), and I am glad were aren't any taller.
God bless,
John
When bay space is at a premium and height is a problem the Crusiair split system is the way to go ( not to be confused with basement air) along with Red Dot dash air
good luck
If I cannot re-install the evaporator (inside unit?) in its compartment, or the second condensor (there were two and I removed the one for the generator radiator cooling), then I must redo and redesign, correct???
The system had leaks, and the plumbing is fitted into the floor running the length of the coach, so I decided it was too much trouble and costly to repair - so I started pulling the end units - front only so far.
Did I make the wrong choice? Can I use the same compressor still, if I reconnect (not touched yet) the rear system (evaporator), driver's system, and one condensor unit, and then repair the leaks in the plumbing. If I recall, the two condensors were plumbed in series, so one evaporator (plus driver's) and one condensor should make the system match up??? Am I explaining it correctly? I am no A/C systems guy (you know I am not kidding !!)
Am I asking too many questions for this forum? I hope not. Are you going to charge me tuition?
Keith
Pcc, what does this have to do with help for our coleman basement units???? ::). No, just kidding, but as mentioned by John, you will get more help with creating your own thread to get the attention and help you need. There are a lot of knowledgeable people on here willing to help. Good luck.
Now, we have solved our problem with what to do about 2 units. We are going to duct one unit to cool whole bus, and the other one to cool just the front area to keep it cool going down the road, as was suggested by someone from the boards to hubby. Thanks for the help, once again. ;D
Sorry, Ruthi. I butted in because your questions seemed to run parallel to the questions I had, but I have taken too much of your space.
Having never started a thread of my own, I guess now is as good a time as ever to learn how it is done, right ?!?!?!
Thank you for your forgiveness.
Keith
Quote from: PCC on November 29, 2009, 07:54:07 AM
Sorry, Ruthi. I butted in because your questions seemed to run parallel to the questions I had, but I have taken too much of your space.
Having never started a thread of my own, I guess now is as good a time as ever to learn how it is done, right ?!?!?!
Thank you for your forgiveness.
Keith
Hey Keith don't be sorry about trying to learn! If you'll click on all topics, you will see a little tab that says "start new topic" just click on that and type a subject line. Then in the message body put what ya want in and post. ;D BK ;D
by the way I sent you this same msg as a PM. But then I thought "what if he hasn't learned how PM's work yet either?" LOL! ;D
What's a PM !!!!!! :))
I did see the marker, and clicked it, and WOW - another something new !!
Thank you
I did reply
While we are on the topic of A/C's....
How do you convert tones to BTU's
Like, if the bus came with a 15ton system, and I have 2 10K BTU a/c's, what percentage of the factory cooling do I have?
Here is a link to a glossary of, and conversion tables for, air conditioning/refrigeration systems.
http://www.bry-air.com/files/trc/Useful%20Conversion%20Factors.pdf (http://www.bry-air.com/files/trc/Useful%20Conversion%20Factors.pdf)
I believe that the conversion is 12,000 BTU = 1 ton.
Nice talking with you earlier, Sir.
Quote from: philiptompkjns on December 02, 2009, 08:34:27 PM
While we are on the topic of A/C's....
How do you convert tones to BTU's
Like, if the bus came with a 15ton system, and I have 2 10K BTU a/c's, what percentage of the factory cooling do I have?
Simple, There 12,000 btu's to a ton. There are 9,000 btu's to a hourse power.
Good Luck
Nick-
thanks guys, that makes these roof/window/portable units seem futile.
I know the feeling (futile) as I work to cool my meat packer !!