Roof Airs

Let me say that just because of the response from you folks makes it worth joining the website. The group of people here are quick to give good honest opinions helpful to those of us not yet experienced in certain topics like say, 3 or 4 roof airs? Its one of those things that you have to experience to know the outcome because both look good on paper. Experience can be an expensive thing to learn on our own not counting the multiple attempts at the same problem. I appreciate everyone taking the time to make a post and hopefully others with some of the same questions may have picked up another little morsel to file somewhere.
I am a master class Sporting Clays shooter and am planning on using the bus for travel to events around the country, not that I will win anything but its entertaining and a good bunch of people there to shoot with. My wife is an excellent needle-pointer and also we plan on trips around the country for classes offering advanced teaching of the art for her. I just don't want to arrive HOT and IRRITATED!!!!

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Originally Posted by jack14r

Jon,I heard recently that when Liberty did the first 3 slide which does not have OTR that they found that there is a vacuum created under the coach at a certain speed(like ground effect on a flat bottom race car).With this new information,assuming that it is true,temperature may not be the problem while underway but instead no air flow to cool the condenser.Also there might be certain speeds that there is air flow and other speeds that the vacuum is created.

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Jack, While I can understand and appreciate how a vacuum can develop beneath the coach, I cannot accept that the two condensing units behind the bumper are affected by a vacuum. Don't interpret my skepticism as being anti Cruise Airs or disbelief that the vacuum is the real problem. It may in fact be a number of issues that impacts the ability of a Cruise Air to function while on hot highways.

Ironically when the bad relay caused my OTR to quit last summer I ran the Cruise Airs by accident with the front shutters closed and they were putting out cold air despite it being in the mid nineties, the first time and only time they worked well while traveling on a hot road.

I agree that the front two should work with the impact of air to the condenser from 60+ mph but almost everyone that has ever run cruise airs under way has had a problem(myself included).I lost a voltage regulator 2 years ago and it shut the OTR down and I cranked the generator,opened the shutters and the front cruise air shut down with hi pressure in 10 minutes or so.My coach with the shutters open has a loud buffeting sound at certain speeds,like the air is not flowing through the area.I know that Liberty modified the airflow on the 3 slide coaches and they did not do it on the first one and it has been a problem as far as cooling while under way.Unless we have actually measured the pressure or vacuum at a particular place we are just guessing at whether there is positive or negative air flow.

The ambient air temperature should not change whether the coach is stationary or moving. The ability of the fan to cool the condensor is obviously the issue. My coach has a deflecter on the front of each outlet which should increase the vacuum at the outlet thus increasing airflow. I'm not sure if all coaches have the same arrangement or not. When I purchased my coach the OTR did not work and I used the cruisairs while driving in 100 degree plus weather. The front and mid worked perfectly but the rear shut down because the condenser and fan were caked with dirt.
The large squirrel cage fans move a lot of air and part of regular maintenance the fan and condenser coils should be cleaned regularly.

Lee, I suspect Jack's newer coach, my middle aged coach and your vintage coach have the Cruise Airs all installed alike. While I agree moving or stationary should not have an impact what happens when we are moving is the air temperature 12 to 15 inches above a heat soaked highway that is radiating heat is going to be different than at the roof line, or beneath a coach that is stationary and has shaded the ground below the coach.

When we had the OTR failure in our first coach and the Cruise Airs would shut down, it was daylight and sunny and ambient temps were in the 90s. As soon as the sun set all three came roaring back to life and we went from sweltering in the heat to freezing. Admittedly the temps dropped, but from mid nineties down to about 85 isn't a significant drop, but I surmise the temp down near the highway went from 120 plus to closer to ambient.

I am now curious so I am going to compare temps outside to temps just above the road when it gets hot out. Too many of us have had exactly the same experience for this to be related to a single coach.

I clean my coils routinely, but admit some portions of the coils are never going to get clean without removal of the entire condensing unit.

If your coach is close to the same as mine the outside air temperature sensor is in the spare tire compartment on the passenger side almost at interior floor level. As you know this is where the condensers draw there air from, so in my case the condenser cooling air must be the same temperature as the outside air. It would lead me to believe that it is an air flow issue rather than a air temperature issue.

Its a theory.

I would guess the only way we will know if it is air flow related will be if we hook a manometer up to measure the pressure differential on one side of the condenser to the other while moving and stationary.

LOL isn't that what I said

Yup...............

Ledo -
I thought I warned you about this group - I said, " Don't ask about A/C, plastic shields, or nitrogen in tires ", But you went and did it anyway! Welcome aboard.