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OTR – Coooold
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Hmmm, what’s an engine driven air conditioning system called? Dash Air is the right answer. But when you have two such systems what’s the other called? OTR Air is generally recognized as that other system. If Prevost trademarked the name, let’s use the right sized engine driven supplemental coach air. Nah…that’s just too many words to describe a very similiar system.
Here’s an interesting tidbit. When a CC was at the Prevost factory in Canada and having problems with his Whatchmacallit air, Prevost did an engineering redesign and he left with a great system. It wasn’t the cool a full windowed bus with 55 passengers version, but one sized for the need.
I had my home AC systems serviced today and asked about the size of my one unit. I thought it was undersized and the tech made a great point. He said a system that cools too quickly can’t remove the humidy. In Florida that’s critical. Newer high end residential systems have a two stage compressor and use the first stage when starting and based on their ability to reduce the temperature may turn on the second stage. I have no idea if this is equally applicable to vehicles, but does point to a variable other than temperature when sizing an AC system.
Just busting your chops,
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Gil, I realize humidity is a consideration, but as anyone with OTR will tell you our systems drip enough water out of the evaporator to supply the average small city. OK I’m kidding, but only a little. We do remove a lot of humidity when the OTR is running and the water drains steadily from the evaporator bay.
What we have recognized as long term owners of OTR coaches is it does quickly remove humidity, and we don’t get that musty odor or sense of dampness. We know how Florida gets and one of the reasons we make extensive use of either the OTR or the Cruiseairs is if we rely on cool ambient air the towels in the shower will never get dry and will mildew. I wish there was some reasonable way to use OTR when parked because it is very effective at handling humidity and the air flow distribution is superb so the entire coach is remaining at a low humidity.
(At 105,000 BTU that would be the equivalent of 7 Cruiseairs so I doubt if a 50 amp shore power would allow my wishes to become reality)
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Ok Guys,
I have a Marathon with the roof tops… once I figured out what buttons I needed to press on my dash air I did have to use the wipers the other day… but just for my knowledge do you OTR users use the OTR while parked as well or is that just for while underway and you have rooftops or something similiar when you are parked…. just curious… I saw a liberty at our park in HHI a few weeks ago and didn’t see anything on the roof but also heard something AC sounding from one of the bays and was just curious.
Bill
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OTR is just the engine driven AC system. Actually it is whole coach heat and air conditioning.
Like dash air or other engine driven air conditioning systems it can only be used when the coach is running. Regardless of the converter all coaches have other air conditioning which is powered by electric, usually shore or generator power, but in some, if not most cases through inverters.
The electric powered (or house) air conditioners can be roof mounted, or mounted in the bays, or mounted in otherwise less useable space such as behind the front bumper. The house air conditioning systems are independent of the Prevost chassis and do not need the engine to be running.
We do a lot of kidding about the coach environmental systems and each of us may have preferred types of heat and air but they all seem to get the job done.
As our coaches evolve however we are beginning to see the beginnings of some standardization among converters brought about by a variety of factors that are pushing everyone in the same direction. True OTR systems as offered by Prevost will not be available on coaches with more than 2 slides so as the market demands 3 and 4 slide coaches OTR will be a thing of the past because there is no way of ducting the air flow on those coaches. That includes converter designed whole coach AC systems as well for the same reason.
The debate about the virtues of roof airs and Cruiseair units also is going away for other reasons. Cruiseairs as we know them have been discontinued so the only viable alternative for future production is going to be roof air units unless someone comes up with a suitable basement package unit or a “mini-split” that will be a viable replacement for Cruiseairs.
All I can say it is going to be pretty boring in Prevost Commuity when everyone is driving 3 and 4 slide coaches, all with roof air. We will have little to debate and joke about.
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Jon must be sleeping in Bill, so I will answer for him!
OTR is engine driven, hence the name Over-The-Road, and is used while driving. When parked the Cruisairs (in a Liberty) or roof airs in other models are employed. Cruisairs are split units where parts are in the bays instead of the roof.
My good deed for the day.
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Dang. Jon posted as I started typing. Still, you can read my post in seconds. Jon’s……not so much.
😉
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Any AC source can be ducted any way you want. It’s just a matter of moving air across an evaporator coil. So, why isn’t Prevost able to duct Prevost OTR air in a coach with slides?
Speculation on my part. The industry as pretty much settled on roof top AC units for parked and over the road. Unlike dash air, dash air can’t really go away, and it shouldn’t. It’s necessary to meet defrosting requirements. Even though as a percentage of the cost of a new coach, Prevost air isn’t much, as a single line item I think it was north of $20K as an option.
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If CruiseAir units have been discontinued, what are they installing now in high-end yachts? Seemed to me that a lot of CruiseAir applications were in he marine industry as well…
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Water cooled Paul.
Our Cruiseairs are unique to the RV market and as such we are using air cooled condensing units. The Marine industry has split systems such as ours but with water cooled condensing units something I doubt will go away anytime soon.
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If this is discontinued, how long will parts be available for the older coaches?
Maybe a better question would be…..what do I do if I need to replace a unit? Are any complete units still available or is it just parts?
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I have Prevost OTR air with 2 slides, and I am so glad I chose the coach with it (after many suggested it especially to cool an H3). It is unbelievable how cool and quick it gets even in 90+ degrees.
The converters did not like it because it was harder to work around duct work, and took up an extra bay, so I’m told.
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Cruiseairs are completely rebuildable. When they were beig produced it was often less expensive to get a factory refurbished unit since one could be swapped out in an hour or two. But if one fails today it is more likely it will be pulled, rebuilt and re-installed. The likely failure points would be the condensing fan, evaporator fan, capacitors or the compressor, all of which are readily available.
I’m not sure about control failure. I think they have been pretty reliable
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I called AAP in VA and they said that Cruise Airs have not been discontinued,Dometic now manufacturers in Florida.
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The web site doesn’t show any air cooled. Just water cooled except for an air cooled unit for radar domes.
If they still are making the split air cooled systems they have them hidden so I can’t find them. But then again it could be my eyes are missing something.
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We buy all our cruisair parts from a big marine cruisair dealer in Kemah, TX… they have always had or ordered what we need but its usually in stock… we have a commercial account with them as both of our Hatteras yachts have cruisairs… they are big units too…. the compressors & evaporators etc are the same as in our bus… just air cooled instead of water cooled.
Diane
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