-
Cruise Air , Roof Air, & OTR
When I see a coach has “Cruise Air” can I assume it has OTR, or the only supposition I can make is if a coach has 3-4 roof airs, it definitely doesn’t have OTR?
-
15 Replies
-
OTR is from Prevost. Cruiseair and roof air are from convertors. A coach could have roof and OTR or cruiseair and OTR. Depnds on the build. Roof and cruise are generally for when you are parked, and require shore or generator to power. OTR os run by the engine and is used while driving down the road.
-
I’ve mentioned this before, we have never had OTR air but have been in many seated Prevost buses when traveling that have had it. It’s perfect for that purpose.
Cruise Air and Roof air run can run from shore power (or generator/inverter). OTR air runs from the engine which is used while driving.
Actually, this week, we are on a river boat cruise down the Mississippi River. Today, it included an out-trip on a seated bus…… a Van Hool (it’s not a Prevost for sure). It had OTR air that worked quite nicely.
In our Elegant Lady, our dash air has an additional ‘aux air’ that supplements the driver’s air. It appears to have 2 additional vents behind the driver’s seat and another vent at the exit door. When both of these air units are operating, it is quite nice. Mostly, just the driver’s air is fine.
We have the ability to run one, two, three or four roof air units from the inverters as we have four inverters. If we need additional air in the coach to supplement the dash air, I might run units two and four. My copilot doesn’t like air blowing in the passenger seat direction so we don’t use unit # one. If it were me, I would have the whole coach at 55 degrees and wearing shorts. I think all roof airs running would work just fine to keep the coach frigid cold!
Even though I could use the inverters to run the house air, I will run the generator to exercise it as it makes an excellent opportunity to do that.
Safe travels,
Mark.
-
I remember when Mark was asking the questions, and now he is answering them. And his answers are absolutely correct.
Good job Mark.
-
M&C,
I thought all Liberty’s came with OTR. You say you have “dash air” which I’ve seen used when someone doesn’t have OTR. “Dash Air” and “OTR” both run from the engine and are different, right?
Also, I’m sure they are out there, but I haven’t seen a Bus advertised yet which has OTR & Roof Airs, but again, maybe they are out there, but just more rare.
-
Liberty’s with more than 2 slides can’t have OTR as there is no place for the ducts. Hence roof airs and Cruise airs on some LIbertys.
Mr. Mark is that accurate?
-
Tom and Bill,
Yes, you cannot get OTR air with three or more slides, two slides yes.
Some Liberty’s will have Cruise Airs installed along with a couple of roof airs. By having just roof air on our coach, we have extra storage cabinets next to the big TV up front. My understanding is that if we had Cruise Air, some of the returns would be in that area.
Tim and Cindy,
Dash air on a coach is just like in your car, it works with the engine running. OTR air is a completely separate system that has duct work through-out the coach at or near the window seals. OTR air works with the engine running.
So, the choices are:
-Dash air (everyone has it)
-Cruise Air, some coaches may have only Cruise Air for cooling/heating (multiple units) that are located in a bay or behind the front bumper, some can have a combination of roof air and cruise air.
-Roof Air, some coaches like ours only has roof air for interior cooling that can be used while going down the road or parked and plugged into shore power. Our roof units are also heat pumps.
-OTR air is used when driving down the road. So, a coach equipped as such will need another form of interior cooling while parked (roof air or cruise air).
Mark
-
We have OTR in our Liberty along with four Cruise-Airs (we have a 24volt, Elegant Lady).
I’m not sure we have “dash air” like other coaches without OTR. My recollection of Jeff Rowe’s explanation is that the OTR uses a large Carrier compressor driven by the Detroit Diesel engine with two evaporators (the things that “get cold”) … one for the large “coach” that is controlled by coach knobs on the dash and another one of up front that is controlled by the driver knobs on the dash.
If a Prevost doesn’t have OTR, its my understanding it has a small A/C compressor driven by the DD engine that provides cooling for the driver’s area.
To this point I’ve believed that something called “dash air” uses that smaller compressor for an isolated area of the coach. Maybe I’ve been believing wrong.
From what I also understand almost all Libertys without slides have OTR, with the exception of at least four coaches spec’d out and sold through Buddy Gregg Motorhomes in Knoxville that did NOT have OTR …. but had three or four cruise-airs only. For going down the road to have A/C in the coach the Cruise-Airs had to run. To the best of my recollection these four or so coaches were of a 1997, 98, or 99 vintage.
So for someone looking at a Liberty it more than likely has OTR, but you should confirm it solidly. We’d hate for someone to pay the OTR premium for a Liberty and get to Jeff Rowe’s shop for zero’ing out only to learn after the money has changed hands that the coach does NOT have OTR!
I’ll sit back and see how accurate I am.
-
You can tell by the pictures of a coach even if you can’t see the engine compartment. The 4th bay door on the curb side will be fully louvered. Geo.
-
3rd Bay. If the engine compartment is shown the large compressor shows it has OTR.
-
We’re both right. 3rd bay on an XL, 4th on an H. Geo.
-
And 4th on the X3
-
3rd bay on my pocket sized H
-
To follow up on OTR vs. Roof A/C or Cruise Air, althought the way I’m asking may be a little convoluted …
Is there a significant “MPG” difference if you’re running down the road and your OTR is on vs. running down the road with two roof A/C units powered by your inverters or, if it was extremely hot, you needed to turn on the generator for a third A/C unit?
What I’m trying to understand that if a coach didn’t come with OTR, could you keep the coach just as cool going down the road, even if you had to turn on the generator for three or four A/C units, and would there be a significant drop in MPG firing up the generator vs. using OTR in the first place?
-
There will be not much difference , don’t worry about the little things plan on at least 6 MPG anything over is gravey. Yes it will keep it cool , but OTR is the best , I have had all kinds cruise airs OTR , dash air and roof airs , OTR and roof airs just what you like , I like cruise airs and OTR air less noise , but can be not as good when sitting outside beside coach because cruise airs blow out under coach
-
This assumes all scenarios to be the same, that is the interior temps of the coach are uniform and consistent through the coach.
Once the temps are stable the heat loss or gain requires a certain amount of energy to maintain the temps. So theoretically OTR, roof AC units or Cruiseairs are all going to have to do the same amount of work and energy is energy is energy. The only difference is the relative efficiency of each source of energy. Does the engine work harder to run the OTR or is it working harder to run the alternator to replace the charge drawn from the batteries via the inverters or is the generator consuiming more fuel than the engine will to maitain the bus temps?
Right now you are talking such slight differences in efficiency I doubt anyone has the ability to measure the differences. I would be worried more about which way of heating or cooling the coach is best to suit my needs rather than the minute differences in operating cost while driving.
Log in to reply.