Roof vs Cruise air

[gmcbuffalo]

The exchange of air for cruise airs being under the bus can be a problem even when parked. I have been in las Vegas and could not cool the coach down with all three CA's running because the condensers were pulling hot air in to cool the system, this hot air will not cool the system, but causes a Hi Pressure shutdown. The venting and pulling of air from under the coach is a design flaw in my opinion for cruise airs.

[Jon Wehrenberg]

I'm not going to defend the design of the Cruise Airs. But if they are properly charged with R-22 they will function quite well when parked because the bus is shading the ground and if the baffles are correct and in place the hot discharge air is carried away from the cooling intake air. Anyone that has serviced Cruise Airs however will attest as little as an ounce of R-22, one way or another has a disproportionate impact on performance. But when they are working right they are very good.

If you are experiencing problems Greg, the first step should be to make sure the hot air discharge is directed away from the intake otherwise the exhaust air is redirected back through the condenser where it gains more heat and this circular air flow causes shutdown.

[aggies09]

To echo Jerry's comments, if you want to sit outside of your coach at football games with the cruiseairs running it can be a blistering hot experience. Loc and I sat between our buses down at Aggieland one weekend with the cruiseairs blowing out towards us like a furnace. One does not require a furnace in Aggieland in September or any other place in the south for that matter. I think Jon is correct in that the days are numbered for cruiseairs and coaches. Frankly, other than being ugly, I think I would prefer the roofairs.

[joelselman]

Cruise airs are very sensitive to proper charging. My first coach (40' 3 CA) had issues in the Southwest over 95F. My current coach (45' 4 CA) will not cool in dry air over about 100F. The only reason I accepted CA's in my current coach is because I was "sold" and the coach has OTR, which lessens the impact.

Don't really know about roof airs; I was at Mira Loma one day when an owner complained his Marathon with 4 roof airs would not cool???

Incidentally, my first coach cooled well in OK City @105F with high humidity. I've heard of people rigging up misters to blow water on the CA condensers in extreme conditions.

[jack14r]

I dry camp on asphalt in Louisville Kentucky for a week every year and I have found that on the hot days 90-95 degrees I can keep the coach 68-70 but I must raise the coach as high as possible to assist in airflow under the coach.As more slides become more common I wonder when the converters will make 5 AC units as the standard.My coach when I took delivery would not cool very well on a hot day,the cruise airs freon charge MUST be tweaked for max performance.

[Ledo]

I have 3 15K roof airs and have had the roof coated with heat reflective coating from CoachWorx in Clearwater Florida before this summer trip. With the bus not heat soaked I can run two airs on low and the galley on auto, which it will cycle off and on and it has kept the bus very cool thru the hottest of days here on this trip in Texas where temps have hovered around 100 each day. While driving I will use the dash air also like everyone else does no matter what system they have if its hot.

[Coloradobus]

Gary Carmichael. To answer your question about window shades and our former Marathon coach's Cruise airs ducted thru OTR ductwork. The air vent slits on our corian windowsills were iinboard of our silhouette shades. We could keep the blinds closed and the vent slits were exposed to blow the cool air aroundthe coach interior.

[gmcbuffalo]

Jon I have not had my CA tweet. But if the coach gets heat soaked (no OTR) while driving I am in for a misserible time while parked. I have checked the intake and discard vents and they are okay. A year ago I installed an additional 12v electrical fan on the Mid CA that supplies the galley(this is the one that has the most problems with Hi Pressure shutdown. I have yet to be in any heat to see if it will help. I may go with Jim Shoen's misters if I need to, but mine will be manual on and off unlike his automatics. I been told that an AC system is functioning okay if it can drop the temp 20 degrees

[Jon Wehrenberg]

I don't know the procedure Jack used to maximize his CA performance, but if I have to work on mine I will use their published R-22 charge amount as a starting point and using my IR gun to read temps make ever so slight adjustments until I maximize the differential. I have heard all sorts of methods over the years such as setting the charge based on pressures, using the "beer cold" method, charging based on the factory volume, etc. but I think our longer runs of tubing dictate charging based on the maximum temperature differential.

As to cooling the condenser Jim Shoen's method is excellent, but if I remember Steve Bennet has a fan set up that increases air flow across the coils and he has had success with that. I do know the exhaust air from the condenser has to be separated from the intake air. Finally, any bus, no matter what the systems should never be allowed to get heat soaked, not only because it makes the AC systems work hard to get the temps down, but some of the laminates are adversely affected by heat and the damage that can occur can get very expensive to repair.

[truk4u]

I have had 4 buses, 2 with cruiseairs and 2 with roof airs and here's my 2 cents:

Cruiseairs
Pros - Cools well, no roof penetration and quiet
Cons - Expensive repairs, difficult to work on due to location, produces excessive heat in patio area, hi temp shut down while driving when you need it the most, poor access to evaporators for cleaning (Liberty you have to remove the refrigerator) and hard to find service locations.

Roof Airs
Pros - Works in any temp, quiet ducted air, cheap to service and/or replace, low amp usage, easy filter cleaning and can be worked on at any RV shop or mobile AC service facility.
Cons - Roof penetration and roof access