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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Skykingrob on December 07, 2010, 07:35:57 PM

Title: Drivers AC Choices
Post by: Skykingrob on December 07, 2010, 07:35:57 PM
Like many of you, I had to make the difficult choice of whether to keep the OTR a/c or not. For various reasons, mainly costly maintance, I removed mine. That has left me with trying to decide what to do and how to do it for options for drivers and co-pilot a/c while driving. Since much of the copper pipe is gone in the middle part of the coach (removed the evaporator/condenser and piping) and not being able to sweat that pipe back together without setting the bus on fire, I am leaning toward some type of front a/c system that is electrical rather than a bus engine driven compressor system. For example, I have a Toyota Prius that uses an electric a/c system. It works very well so, I went to eBay to see if there were systems removed from other Prius that could be put into the front of my bus and if so, what would it cost and how would it work. It remains an option but am not sure it is big enough for a bus and the cost is pretty high at $1000-1400 for a small unit. I know about polar king, thermoking, red dot and some others but value the information you folks have stored up in your collective brains. I also think maybe some of you have done what I want to do and I could just steal your ideas without having to do all the investigative work myself!!! LOL
I plan to travel this whole country in the bus so will need varying cooling capacity such as little up north to max in the south. I like to be cool when driving. I have installed 2 Coleman basement heat pumps (total of 4 units) in the bus currently and could run them using the generator while driving but am looking for other options where I don't necessarily have to run them and generator while going down the road.
So, what say you about ideas.
91 Prevost LeMirage XL40

Title: Re: Drivers AC Choices
Post by: robertglines1 on December 07, 2010, 07:46:50 PM
wasn"t yours  equipped with factory drivers air with a separate compressor? If so you should have separate hoses run from front to back and a evaporator coil in the same compartment as the front drivers heat /defroster/ac. if evaporator coil is there and not hooked up you could run new hoses from the back to it and use a auto air compressor to feed system and add a condenser coil at radiator. ck and see it might already be there.  Both of my prevost had it. the 89 and 98. If small compressor is missing let me know I might have a extra(24 volt clutch)   The aux air/drivers air is 2 ton.  Bob

Title: Re: Drivers AC Choices
Post by: TomC on December 07, 2010, 09:02:23 PM
I run my roof airs going down the road with the generator running.  Also have an electric 12v dash fan that blows on me-works very well-even driving into the sun.  Good Luck, TomC

Title: Re: Drivers AC Choices
Post by: scanzel on December 08, 2010, 03:42:41 AM
I have an 89 Prevost, formally a coach not a conversion and it only has one big Carrier 05G compressor that runs the otr and the drivers area. Conversions may have it differently. I chose to keep my otr because I did not want to run the generator for my roof tops and what happens if the generator goes out, then your traveling in a sweat box. I also looked at removing the otr but then to replace it with something else comparable was thousands. Instead I had my otr fully gone over, with rebuilt compressor, system flushed and totally checked etc. Sure it cost me $4300.00 dollars but if it fails then I can still use the roof tops with the generator. I wanted some redundancy. Redot is great stuff but $$$$. This is just my view on the subject and as usual we bus converters do it our way, that's what makes us unique.

Title: Re: Drivers AC Choices
Post by: belfert on December 08, 2010, 03:59:01 AM
I don't undertand the need for A/C redundancy.  Regular automobiles don't have backup A/C if the A/C fails.  I don't personally know of anyone with backup A/C for their home, but maybe it is done in the south.

We each do it our own way.  I would like to install driver's A/C for on the road with a small automotive type compressor, but it may never make it to the top of my list.  I don't really drive enough in hot weather to justify it. 

Title: Re: Drivers AC Choices
Post by: robertglines1 on December 08, 2010, 04:33:42 AM
Steve the 89 was a seated coach when I got it and had drivers a/c. with separate air compressor.  I just retained it because it was there. The 98 also but it is a salvage Entertainer coach.   Bob

Title: Re: Drivers AC Choices
Post by: Joe Camper on December 08, 2010, 05:31:36 AM
Belford if you ever been in a Prevo on a very hot day without OTR a/c or without it working and have even 1 of the 3 house airs go down too, you will understand the desire for redundancy. It ain't producing any happy campers.

We have it too and spent big doe fixing it and we too think it was worth it.

The only thing I would change it the drivers loop I would power it with a separate smaller second engine driven compressor so during the times the entire bus did not need cooling we are not forced to run that large compressor just to power the drivers loop. (spring and fall we live in Chi)

As for the thread If I were where you  I would install a good used inverter (I have a used 24v 2800w heart that would work great for 500 bucks) something dedicated specifically to running an a/c while underway, and I would put a 15000 btu roof a/c new (700 bucks) and this set up will under most conditions keep you pretty comfortable up front for not too much doe.

On a side note I run my cruseair off a smaller inverter (after many told me it was stupid to try) a 2500 w Heart. The cruisair pulls 12 to 14 amp depending on fan speed still leaving me  6 or 7 spare amps for other continuous loads like the TV/DVD and other misc small draws.
Sorry for the shameless plug ::)

Title: Re: Drivers AC Choices
Post by: eddiepotts on December 08, 2010, 05:40:44 AM
You might want to try these guys. http://www.classicautoair.com/ (http://www.classicautoair.com/)  I have never used them but they have been doing custom air for years. You might be having to install a drivers curtain to reduce cubic feet of cooling area. I do not think you will find anything that will cool the whole bus.

Title: Re: Drivers AC Choices
Post by: bottomacher on December 08, 2010, 05:41:21 AM
If you look at the glass area that surrounds the driver's cage and add the fact that windows don't roll down, it's pretty easy to see the desire for redundancy. And summer happens, even up north.

Title: Re: Drivers AC Choices
Post by: Mex-Busnut on December 08, 2010, 06:09:05 AM
I am curious: How much horsepower does  typical OTR air conditioning system steal from your engine? I know on a typical automotive system, it can run from 10-25 horsepower.

Title: Re: Drivers AC Choices
Post by: Joe Camper on December 08, 2010, 06:21:30 AM
 The factory otr compressor for ours is a 6cyl, 3 head, 10 ton 75000btu monster designed to keep 50 people cold on a 100 degree day. It holds 24lb of refrigerant.

I would guess it probably takes 3 times that much HP to power it.

Title: Re: Drivers AC Choices
Post by: lostagain on December 08, 2010, 06:59:27 AM
In the 5C, we run the front roof air off the 3000 watt inverter. Close the back louvers, and point the front ones at the driver and copilot. Works really well.

Maybe you could run a duct along the ceiling or along the sides below the windows to blow cold air at the front for driving.

In the Courier 96, which only had one roof air and it was too far back, I installed a roof mounted swamp cooler. I ran a 1/4" water line from the cold water supply to the bathroom sink to run it. Had to leave the water pump on for pressure. That kept us quite nice and cool up front as long as the weather is dry, would not work well back East in the humidity.


Title: Re: Drivers AC Choices
Post by: rv_safetyman on December 08, 2010, 07:56:13 AM
Wow, the search feature on the main toolbar is really messed up!!  Wish we could get that resolved.  Folks need to be able to search past posts.  I went outside the forum and did a Google search and found this thread:

http://www.busconversions.com/bbs/index.php?topic=5273.0 (http://www.busconversions.com/bbs/index.php?topic=5273.0)

As noted in that thread, this subject comes up a lot.  I started the above thread to detail my system.  It works quite well for most conditions.  We have the ability to close off the back half of the bus and that helps.  Our bus is not well insulated (roof insulation has not been changed from the standard crappy OEM insulation (yet)), but I am not sure that makes all that much difference with all of the glass up front as others have mentioned. 

Early on, I mounted a third roof air towards the front.  It is a Carrier that has the "shower" feature (can dump cooled air straight down) and I closed the rear vents so that all of the air was forced forward and down.  It did not do the job.  When I ran the second roof air it got us to a reasonable level, but not as good as we wanted.

The RedDot unit really does a great job, since we can direct the air where we want it.  I also plumbed the defroster into the back and can run both heat and AC to defog.  In that thread, I talk about using the AquaHot for the heat source - wonderful choice.


Title: Re: Drivers AC Choices
Post by: dougyes on December 08, 2010, 08:07:40 AM
The MCI-J conversion coaches come from the factory with a 24 volt drivers ac mounted in the tire bay behind the bumper. 
A Prius ac unit will barely cool your arm pits in that green house we call the drivers compartment.

Title: Re: Drivers AC Choices
Post by: robertglines1 on December 08, 2010, 08:13:29 AM
one thing we added in the 89 and will put in the 98 is a ceiling fan over the driver. It is a 20 inch 3 spd unit from Lowe's ceiling hugger.$45 in winter will pull heat of of ceiling to help balance out layering of temp. In summer will pull cool off floor past driver and passanger and help move heat from windshield away from front. is small enough that it doesn't present a headache area. I bought a 12volt clutch bogwarner from a truck wrecking yard(ac compressor) that will supply enough freon to the drivers air evaporator $45.  Also on front windshield I put a strip of mirror tint  down to 3 inches above the line of site Aprox 12 inches and covered the top small windows completely.Big difference. Just some possible solutions I have tried and was pleased with. Bob

Title: Re: Drivers AC Choices
Post by: Zeroclearance on December 08, 2010, 10:18:59 AM
Does anyone know of any used CruiseAir takeouts?

Title: Re: Drivers AC Choices
Post by: luvrbus on December 08, 2010, 10:33:33 AM
Zero, Jim Smith has 3 he took his out because the so called Pro converter ran the copper where you could not repair lines he never said but I believe he drilled holes in the lines lol Jim Smith (Smiths Ultimate Linings) 1- 505-332-1403 Alb NM 

good luck

Title: Re: Drivers AC Choices
Post by: Zeroclearance on December 08, 2010, 12:32:00 PM
Clifford  :)  Thanks for the leed.    Jim has two!

Title: Re: Drivers AC Choices
Post by: scanzel on December 08, 2010, 02:04:36 PM
I choose to keep the otr air because a few years ago after stopping at a Lowes to pick up a few items I came out and the coach was probably 100 plus degrees inside, started up, hit the otr switch to find out it wasn't coming on. Compressor clutch not engaging because of low pressure of freon. Was not fun driving home. With 680,000 miles on the coach I figured it had finally needed updating. Sure there are other alternatives but after checking on prices and options, it was the lesser to just update the system already in place. Because I work with computers and telecom systems I like a redundant system in case a processor fails the other takes it's place. Some day when possible I would like to have the driver air on a separate compressor. Until then to each his own way. That's why we are the way we are. Unique !

Title: Re: Drivers AC Choices
Post by: busnut104 on December 08, 2010, 02:28:26 PM
I installed a Welsh unite. used the org. dash coil and I added on mid ship for other cooling.

Title: Re: Drivers AC Choices
Post by: Sean on December 08, 2010, 04:58:42 PM
The factory otr compressor for ours is a 6cyl, 3 head, 10 ton 75000btu monster

FWIW, Joe, it's got to be either 10 tons, or 75,000 BTU/hr -- it can't be both.

10 tons is 120,000 BTU/hr.  75,000 BTU/hr is 6.25 tons.

In A/C circles, it takes about one HP per ton of cooling, so a 10 ton unit would require about 10 hp.  However bus systems are a little different and there are more losses; I would figure twice that.  Also remember that OTR air has enormous electric evaporator and condenser fans, which use up a good deal of the 270-amp 50DN alternator; that, itself, uses 10 HP or so.

None of which matters to the OP, who states that he has already removed the OTR air.

Again FWIW, our bus had driver-only compressors and condensers when we got it.  Both compressors seized and we ripped it all out.  Since roof air is not an option in our "downstairs" driver area, we coupled a 120-vac Copeland refrigeration compressor to Red Dot evaporator and condenser units, each with 24-volt fans.  Works great, but the roughly 15,000 BTU/hr it provides is barely adequate in such a poorly insulated, glass-intensive area, especially when driving into the sun.  We chose R134 for the charge.  We also had to have all the hoses custom made, since refrigeration and automotive components use different couplings.

This unit pulls a good 15 amps when it's running, and occasionally trips the 20-amp breaker when starting.  Probably I need a breaker with a longer delay, but it's not enough of a nuisance to bother.  Our 4kW inverter easily runs both this unit plus one of the three roof airs while running down the road, and the alternator still has power to spare to charge the batteries.

http://OurOdyssey.BlogSpot.com (http://OurOdyssey.BlogSpot.com)

Title: Re: Drivers AC Choices
Post by: gus on December 08, 2010, 05:28:21 PM
I solved a lot of the inefficiency of my front rooftop by cutting a hole in the ceiling housing so the air blows straight down to the floor. Blowing it out the side and diffusing it does not work!!


Sometimes I can make Search work by going to Profile first.

Otherwise it gives me fits!!

Title: Re: Drivers AC Choices
Post by: jbnewman on December 08, 2010, 06:27:35 PM
I am curious: How much horsepower does  typical OTR air conditioning system steal from your engine? I know on a typical automotive system, it can run from 10-25 horsepower.

For the MC-9, per its maintenance manual:

  • The system is designed to provide a nominal 7 1/2 tons main A/C and 1 ton driver's A/C of refrigeration or 90,000 Btu per hour heat removal.
  • The current draw from the engine for the evaporator blowers should be 48-52 amps at 27.2 VDC

  • Manufacturer: Carrier
  • No. of Cylinders: 6
  • Horsepower: 25, nominal
  • Weight: 142 lb.

Condensor Fan and Motor:
  • Manufacturer: Ohio Electric
  • Type: 24 V, 2 hp continuous duty
  • Amperage Draw: Rated 71 Amp, Average 52 Amp

Evaporator Fans and Motor:
  • Manufacturer: Reliance Electric
  • Horsepower: 1 1/2 hp
  • Volt: 24-28 Volts
  • Amperage Draw: Start-Up 70 amps, Running 53 amps



Title: Re: Drivers AC Choices
Post by: Skykingrob on December 08, 2010, 07:00:32 PM
Hi Guys
I was suprised to see the amount of response. Yes, Jim, I know this is discussed alot but as you already found, the search function, at least in my hands, doesn't work well so it really does not help me.
No, Robert, my unit was one huge engine drivver Carrier compressor for the drivers A/C, the coach OTR and an auxilary unit at the back of the coach. I know I can put an engine driven compressor and run all the lines but I was exploring the options that would allow me not to have to do that.
I have cabinets covering the entire front of my conversion down to the level of the windshield top so there will be some help but with all the glass I am sure there will be a need for more A/C that is upplied by the 4 basement units. I may be wrong but I don't think so.
I do still have the dash coil which I keept because of the heat it will produce when supplied with hot antifreeze. All I need to solve is to get freon moving to it the easiest, least expensive and most effecient way for dash air.
Doug, I am with you, I too thought the Prius system would be sorely lacking given the green house effect of the area in question.
I am going to look at the suggestions made here but it looks like the best so far is to simply let the SW 4024 inverter run one of the basement units, close off all the rearward vent outlets, open only the very front outlets and run dash fans to circulate the green house air.
I have an aquahot and the front dash coil hooked up to coolant from the engine which will supply defrost and drivers heat so I am not concerned about heat.
Sean is right, I do not have the engine driven compressor, the condenser or evaporator coil, their fans or the copper tubing from the front of the engine compartment to below the mid part of the coach. As I said, I could put those items back in but in smaller versions to handle only the drivers area but wanted to see if anyone solved the problem satisfactorily without doing all that work. It appears some have, that's what I am looking for.
Thanks for your responses and I welcome any more ideas.

91 Prevost LeMirage XL

Title: Re: Drivers AC Choices
Post by: luvrbus on December 09, 2010, 10:39:20 AM
Rob, I have a friend that uses the Red Dot hydraulic driven system on his Eagle seems to work good for him

good luck

Title: Re: Drivers AC Choices
Post by: Ericbsc on December 09, 2010, 06:28:13 PM
I bought an air, heat, defrost unit from Ron the bus nut. I used a std gm compressor  mounted on the engine. Works great. Cost for unit was about $350.00 best I remember. Everything less than 1k.
(Didn't have lines run when pic. was made)

(http://inlinethumb17.webshots.com/40080/1365852916053449967S500x500Q85.jpg) (http://home-and-garden.webshots.com/photo/1365852916053449967GOsXWy)

Title: Re: Drivers AC Choices
Post by: Joe Camper on December 10, 2010, 03:20:38 AM
I once thought I knew a few things.

After buying this camper the amount of knowledge that I have acquired in the relatively short period of time since we purchased it is ...........cant even find a word to define it, for me, it has been and continues to be that large.

Sooooooooooo I have and will continue to spout out some very ignorant things from time to time LOL Thank you for that correction.

For the record what is the correct spec for this compressor we have.

JB newman GREAT first post thank you for that.

Title: Re: Drivers AC Choices
Post by: Mex-Busnut on December 12, 2010, 08:07:52 PM
Thanks to all for posting your educational replies.

How many of you have tried the ceramic roof paint to lower the temperature inside the bus? How much did it help?

I am supposing the inside of the roof can also be improved with better insulation?

Thanks in advance!

Title: Re: Drivers AC Choices
Post by: Lin on December 13, 2010, 10:53:51 PM
We use the front rooftop powered by the generator while on the road.  Our problem is that the unit is installed in the middle of the living area.  It really should be as far front as possible.  We also have cut a hole in the bottom of the unit, but instead of letting the air drop downward, we installed an adjustable flap that sends the air up front.  Aside from closing off the rear vents, I adjust the flap so that it is closed enough to give the air some velocity but not create enough internal pressure to send any air backwards.  It has worked okay with just closing the door to the bed/bath area, but we are generally happy at around 80 degrees.  If I wanted it to work better, we have a curtain to hang just behind the unit to make the cooled area smaller.  I have thought of putting some sort of unit in the spare tire compartment, but the easiest thing to do would be just to install another roof unit way up front.  This would give us some backup as far as the AC units go, but the weak link for redundancy would be the generator itself.

Title: Re: Drivers AC Choices
Post by: kingfa39 on December 15, 2010, 05:44:24 PM
have a automobile a/c compresser, a condenser over part of radiator and two evaporators in my 06, for several yrs always works great and that 8/71 dont even know when it turns on
Frank Allen   4106

Title: Re: Drivers AC Choices
Post by: Oonrahnjay on December 15, 2010, 07:04:36 PM
Frank, are you saying that you run two evaporators off a single compressor?  That sounds useful.  I have been thinking of another question.  Is it possible to run a "Y" compressor; that is, an engine driven compressor for when the engine is running and also an electrically-powered one for then it's not -- but having the output put into a single evaporator (and condensor system)?  Sorry if these questions are too stupid but I'm not familiar with anything more than a simple 1 - 1 system.
Thanks,  B Henderson NC USA