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Did I Get This Correct? OTR and Cruise Air
It’s been a while since I posted on PC and allow me to take a moment to reintroduce myself.
I’m Andy and I’m getting pretty close to buying my first coach. At least, I hope that’s the case! I’ve been shopping for my first coach for more than a year and it seems I keep going around in circles and making a nuiance of myself on various motorhome forums, but for some odd reason (maybe it’s that quality thing), I keep ending up here at PC. Yes, I took a lengthy detour and considered buying a new Class A, but I kept hitting potholes. It seems that brisk sales has caused the manufacturers to forget they are making “recreational” vehicles and are now producing new ones that include very long punch lists. Maybe I don’t have a sense of humor, but I don’t see too much recreation in camping out at a dealer’s service center for a few months awaiting my turn for service to be peformed by someone who is geting a bunch of on the job training and using my motorhome as a science experiment. I’d much rather be hanging out and sipping a nice scotch at Blue Water Key in the Winter and overlooking the Rockies in Breckenridge in the Summer. But, I digress…
I’ve consulted some fine folks who are much smarter about these things than I am, and I’m attempting to learn more about Prevost conversions. So here I am. I think I’ve woken up and am now looking at gently pre-owned Prevost models.
Today I learned something about air conditioning units. I’m not saying I got it right, so if I didn’t, I hope you guys are gentle to this newbie and don’t kick me where it hurts. Here goes:
A coach I’m starting to get serious about has both four Cruise Airs and an Over The Road air unit. Honestly, before today, I thought it would have one or the other, not both. If what I was told is correct, this means there’s no units sitting on the roof of the coach and the guts of these systems reside in the bays. One on the port and one on the starboard.
Am I correct so far?
For the OTR air, I’m to understand that I should think of this like a car’s A/C. The engine drives the compressor that cools the coach. The OTR can only be used when the engine is running and cools the entire coach from stem to stern. If the coach has been sitting in the Las Vegas Summer sun for a few weeks, just crank up the engine and turn on the OTR and that’s a pretty efficient method of getting the coach cooled down. If it works well, I should be looking for a sweater within an hour. This also blows the cool air through the dash vents to keep the driver and passenger comfortable while cruising through the desert.
How’s That?
Now, let’s get to the four Cruise Air units. After cruising through the desert with the cabin and cockpit at 68 degrees (did I say I like a cool coach?), I pull into a full service motor coach resort. When I shut down the engine (turning off the OTR air) and connect to the 50 amp shore power, I then turn on the Cruise Air. This system keeps the coach cool while parked and works either via the shore power or with the generator.
Did I get this one right? If yes, I’m going for the hat trick with one more…
What’s very cool (pun intended) is that both the OTR and Cruise Air systems utilize the same interior vents. Is that correct?
Again, thanks to the seasoned pros for putting up with this rookie nonsense.
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13 Replies
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Andy,
Since you haven’t gotten any responses yet, I’ll jump in. Generally speaking, you are pretty close on most points. Be aware different converters may set CruiseAirs up differently, so I’ll tell how ours works. First, you’re pretty much on target on the OTR, except our CruiseAirs do not use the same vents or fans as the Prevost OTR system, and I don’t think any converters use the OTR ducts for CruiseAirs–anybody who knows something different can jump in. We have four CruiseAirs. The cockpit AC evaporator is directly behind the driver and blows straight up–some converters or owners put a diverter on top of the outlet to get better diffusion. Our salon AC is mounted in the ceiling in front of the passenger seat, the vents blow straight back in the salon, and it also has vents that blow down into the cockpit. Our galley AC is mounted behind the refrigerator, and has vents above the refrigerator, in the bathroom, and in the toilet area. The bedroom AC is mounted inside our Techlink closet on the passenger side, and has a vent near the ceiling on the same side.
The Prevost OTR system has vents in the bedroom, the bathroom, on each side of the salon, and a vent each for the driver and passenger. I suspect if you have two slides, you probably only have vents on one side of the coach, and if you have more than two slides, I understand Prevost OTR system is not available.
On the road, we alternate between running OTR and CruiseAirs on generator. We have had both a CruiseAir go out on high pressure, and also the OTR system. When it happens, we switch to the other system for a while–always nice to have both.
We have been running two CruiseAirs at the house with the coach in the sun at 100 degrees, and with thermostat set at 76 degrees, it kept it reasonably cool inside. Our friends just got here with their Prevost, and since we use a buddy plug system, I’m now running on just one CruiseAir. Definitely warmer, but not intolerable inside our coach.
But we love having both CruiseAirs and OTR, nothing like redundancy when you’re dealing with sometimes temperamental mechanical systems! -
Thank You!
The coach I’m referencing is a 2006 Liberty XLII. Does it work in a similar manner to what you described?
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It may be similar, however, XLIIs typically only have 3 CruiseAirs. The best person to explain AC systems on a 2006 Liberty XLII is Jon, who has one. He can tell you all the in and outs of the Liberty CruiseAir systems.
If the coach you are looking at is the one Jeff Rowe has for sale, you can’t go wrong if the floor plan and equipment works for you. Jeff will treat you right, and we met the good people that sold him the coach. You can’t do better than buy a coach from Jeff! -
You get a good grade on your essay Andy because you almost have a prefect score. Only two errors, both minor.
The Cruiseairs as Per points out have their own vents and distribution system for supply and return air. Minor misunderstanding. Even less important is where the Cruiseairs are located. In a Liberty two are located behind the drop down front bumper, and two are located in the center of the coach in line with the 2nd bay back. Despite their locations they can be accessed by a technician relatively easy for service.
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Andy, if you are looking at that vintage Liberty take note of at least 2 items. If the waste tank has not been changed out…make sure it is…and not with a Liberty one. Also check to see if the CAC has been replaced…and not with OEM. If the bus you’re looking at is the one at ELTC, Jeff will certainly clue you in. Good luck in your search. Geo.
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Thanks Jon,
I have a pretty good teacher! I’m hoping that I got at least a B on my first test!
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Thanks, but remember, I’m a newbie and I’m not familair with the acronyms yet.
Can you tell me what’s a CAC and what is ELTC?
The good news is that I know what an OEM is! And, in the case that other newbies are watching this thread, that’s the Original Equipment Manufacturer.
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CAC……….Charge Air Cooler
ETLC……..East Tennessee Luxury Coach.
Regarding the CAC, it is on the pre-buy check list. Likely has been changed, but just need verification. The holding tank issue has already been discussed.
Your grade on the fist post is an A. The minor errors dropped the score from a 100 down to about a 94,
Regarding the comment about the use of acronyms, really????????? I’ll bet you use a smart phone, send and receive texts and use abbreviations or acronyms far more than we do on this site. LOL, FWIW, IMHO.
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And those are the only 3 Jon knows.
1999 XLV X-6872, liberty #440 -
Hey John,
The funny thing is, I still attempt to spell words out as I don’t want people to ROTFL or LOL when I get one of those acronyms incorrect!
Thanks for the definitions and spelling things out for me.
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George is 100% correct. I might know some others, or maybe can figure others out, but the chances of that happening are slim.
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I have owned 2 coaches with cruise air’s; a 1990 Marathon 40 with 3 units and my current 2000 Liberty 45 with 4 units. Neither coach would cool in dry southwest sunshine with ambient temps over 95-100F with the cruise airs. They’ll do a little better if you’re in a humid area but you can forget about Vegas in summer.
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We have learned that the definition of cool or comfortable is dependent upon the person defining it. I like it cold. By cold as I have said often is when the windshield is sweating on the outside.
Having said that I am fully aware I can have the ability to cool my coach with only two Cruiseairs, or I can fail to get it cool with all four working.
First, My XL coach had no double pane windows so in the winter the cold spilled off the windows onto our shoulders and in the summer the heat could be felt just by moving my hand near the window. The XLII windows have eliniated that problem, and I further assist my Cruiseairs by closing the shades on the sunny side so I am not getting radiant heating from the sun.
My window shades in the front when they were black radiated heat into the coach to such an extent the front Cruiseair couldn’t keep up. Now that I have light colored privacy front shades that problem has gone away. I never let my coach get warm. Cruiseairs are OK at maintaining cool temps, but if the interior gets heat soaked that mass of cabinetry, upholstery, flooring, etc just keeps pouring heat inot the air so by keeping it cool inside all the time the Cruiseairs do not have much work to do. The same applies to roof airs.
I also do not lower the coach so I get ample air flow to the condensers and I avoid parking in tall grass for that reason. If the ground surface under the coach is hot, I am going to flush it with cool water so the condensers have a chance to do the job.
I also bias the operation of the Cruiseairs to where we are in the coach. The front may have two Cruiseairs running during the day, but as we get inito evening we shut down one front AC and turn on the aft AC. By running two we can afford to run any other electrical devices without much concern about exceeding the shore power limits.
If a coach does get heat soaked the only effective way to bring the temps to a level easily controllable is to start the engine and supplement the house AC units with dash or OTR. The more cold air that can be introduced the quicker it gets comfortable and easy to keep comfortable.
It is my opinion only 3 AC units for a 45 foot coach, especially one with slides is marginal at best. If one fails you might be able to get the interior cooler than outside, but not much, especially if the failed unit is where you need the flow of cold air.
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