maiden voyage

Just got back home from a 3 week, 5000 mile trip. Five provinces and five states. Great trip for the maiden voyage. Everything ran perfectly. The OTR needs attention, recharge but I suspect an upgrade will be on the agenda but will I'll deal with that later. The three cruise airs worked fine.....good to go in the northern areas at this time of year.

Question: Hot flashes. I know what the wife means now...... I sure someone can answer this. Traveling down the road for a couple of hours, I'll get flows of very warm air in the drivers compartment, even with the front and mid cruise airs working. It comes and goes. Every 10 -15 minutes and continues on. I thought it might be the two vapourisers? working hard in the front, below the cabin. .......but I turned off the cruise airs and it continued,,,,,,, even over a long cool down period of time...... any ideas? Is this common.

Over the three weeks and all the country we covered, I only saw four other prevost conversion coaches on the road.......
Alberta, Saskatchewan, Manitoba, Ontario, Quebec, NY State, Michigan, Illinois, Minnesota, North Dakota

Darrell drop your front bumper and look over to where the bottom door hinge is there should be a box built around it and sealed up good.

If that lower hinge enclosure is compromised it will cause a draft.

Also the control for outside air or recirculate leaks like a screen door on a submarine, even on recirculate it is still letting in much hot air. The damper sucks.

While the bumper is down you can tape up that intake it is on the upper edge of the bumper compartment. Duct tape 10 inches.

What do you mean by vaporizers? Did you have the fresh air vent closed? You should be able to close it by turning a knob on the lower center of the dash.

GregM

I'll drop the bumper and check that out tomorrow. Your right, It didn't make much of a difference playing with the recirculation or fresh air controls.

Thanks

Vapourisers? Condensers? I'll figured that out later but the forward and mid cruiseairs are located below the cabin behind the front bumper.

The half of the cruisair that is in the basement is the condensing unit and the evaporator is the component in the dash.

Darrell I had a couple other holes I sealed up too.

Prevo cut a square hole where the a/c lines come up from the bumper compartment that was letting air in.

The last one you will not get to without considerable effort.

Darrell,

This is a little more specific to your Liberty.

Your fron and center cruise air condensing units are behind the bumper. They are not enclosed except within their own housing.

They are designed to pull ambient air through themselves and pass it through the copndensing coils and discharge that heated air out the bottom. You should make sure the coils are clean and not covered with an accumulation of debris.

Use a soapy mix of something that can clean the coils. If you use Simple Green use the kind designed for aviation because the regular stuff attacks aluminum. Rinse it well with a hose but not a hard spray. There is a fan motor, and a couple of capacitors in there so don't go crazy with the water. You want to use a volume that wets and rinses the coils, but does not get the interior of the condensing unit completely soaked.

That is all you can do to insure the most efficiency.

What I think was happening was the condensing units were not getting sufficient cool air and the units were shuitting down. If the units cannot cool properly the internal freon pressure rises and when it exceeds a certain value the Cruise Air compressor ceases to function. Your warm air was heat being given up by the evaporator coils. As soon as the freon cooled down, pressures dropped and the units begain cycling as they should.

We have discussed the inability of Cruise Airs to function as over the road air conditioners as well as roof air units do. Roof air units are not bringing air heated by the highway into them, but clean cool air from 12 feet above the highway. The Cruise airs work well when pulling air from beneath a parked coach.

If your OTR does need a recharge try to stick with R-12. It is pricey, but if your system checks out it is the most efficient refrigerant. If you switch to 134-A it is cheaper to recharge, but you lose about 15% of the systems performance. I would guess that the system has a small leak at the seal behind the clutch on the compressor. Look for evidence of that in the form of oil behind the clutch. That is an easy fix and a competent guy can change the seal in a couple of hours or less. Test with nitrogen before recharging an if the system hold pressure you are good to go.

Darrell,

Make sure your shutters are open when using the cruiseairs while driving. The default position is closed, so you have to use the button on the dash to open them while driving. If the shutters are closed, the cruiseairs may shut down like Jon stated. When I open my shutters while driving, I also get a slight blast of warm air. All of this is providing your vintage has shutters like mine.

Darrell,

Since I do not have cruise airs, my experience is limited with these units. However, if you are using the Prevost dash air at the same time to circulate or generate additional cold air in the drivers compartment, be aware that Prevost uses a solenoid to control hot engine water from the dash air heater core. The dash air heater core is in series with the AC evaporator, so any leaks through this solenoid, intermittently or continuous, will manifest itself in warm air coming through the dash air vents.

I recently overhauled my dash air and could not get really cold air to discharge from the vents. When I first started the coach, the AC vents would register 47 degrees discharge air(Great!), then after running the engine for 5 - 10 minutes, the temperature would rise to 55 degrees. My 'extensive' investigation revealed the heater water supply line going to the heater core was hot, 107 degrees, but the heater discharge line was 68 degrees. The dash ac system was cooling the leaking hot water through the heater core/evaporator assembly, thus the high discharge temperatures from the vents. This was a tricky issue to find. In my humble opinion, rubber is the enemy of these older coaches.

Problem was solved with the purchase and install of a solenoid rebuild kit from Prevost.

Though you would like to be aware of this small detail that can effect the AC cooling in the drivers compartment.

Hector

Hector
Where is this solenoid located? My Dash heater/AC has a knob that controls it (I think). All the way clockwise there is click and it stops. Turn it CC and it has a large range of motion. The last time I used the coach I didn't notice much differences in the position of this knob. There are two separate knobs for the fans. I forgot to put a manual lever in the engine compartment in the summer mode. The reason I ask where this solenoid is located is I am wondering if I have solenoid or just a manual lever.
GregM

Quote:

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Originally Posted by gmcbuffalo

Hector
Where is this solenoid located? My Dash heater/AC has a knob that controls it (I think). All the way clockwise there is click and it stops. Turn it CC and it has a large range of motion. The last time I used the coach I didn't notice much differences in the position of this knob. There are two separate knobs for the fans. I forgot to put a manual lever in the engine compartment in the summer mode. The reason I ask where this solenoid is located is I am wondering if I have solenoid or just a manual lever.
GregM

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Greg,

The heater solenoid is located behind the front bumper, in the upper portion of the area. I lie on my back in this area and the solenoid is above. My solenoid is hard piped with a copper, with hoses tied in.

In my Country Coach, the knobs that I have appear to be similar to yours. I have two knobs, one that controls the fan speed. The second small knob controls the heat. The electrical diagrams show the knob intergraded with a temperature sensor to control the heat.

I have not checked out the circuitry to see if mine functions as designed, but looks simple enough. I am not sure what actually controls the amount of hot water flow for heat control, but if the solenoid is leaking, hot water will leak through the heater core resulting in a 'warming' of the air you are cooling through the AC evaporator.

Also, my Prevost has two 1/2" block valves in the engine compartment to block the heater hot water, supply and return.

Hector

Greg it is on the ceiling of the front bumper bay center passenger side.

Never got to the explore the depths behind the front bumper today. That will be done over the next couple of days.

Thanks for your input guys. Condensers / evaporators.. got it.

I'm a little confused with closing up all openings and then making sure the shutters are open. Are we taking about the same.

The back of the compressor is clean with no evidence of a leak. Leak at a hose connection somewhere is my guess. R-12 is just about impossible to purchase here. I have heard horror stories of an upgrade to 134-A costing in the $6000.00 range.

Another question: What the hell is a front air baffle. I have a switch on the RH dash for it.

Your air baffle is shutters that are controllable from that switch that are mounted right to the backside of the bumper when you fold it down. That air intake for your dash fresh air I was referring to will be a slotted screen covered opening in the top lip of the spare tire opening itself.

Jon probably has nailed your problem your cruise airs are probably overheating and shutting down but I would still go over all the other suggestions, all are common and combined will add up to a big improvement.

Can we all agree that if you have a bus without Prevo OTR A/C and you will be running 2 a/c's off of inverters to cool the bus while underway those a/c units HAVE TO BE roof airs or you are risking not being able to cool the bus while moving around on very hot days?

Thanks Joe...... I agree with your comments. I definitely have to get my OTR fixed before we head south again.

Darrell, if you have shutters (or baffles) they are likely air operated and are behind the bumper, installed to the bumper. Mine default to open position. If you have them determine your default position, and if they are normally closed that could have been why the cruise airs were shutting down. They were not getting enough cool air to condense the freon.

I doubt if this relates to the bus heating / cooling system and its solenoid valves if you were not using OTR.

Joe,

You will have to define "very hot days." Two cruiseairs running off the inverters or gen, will in fact keep the bus comfortable on what I consider hot days, temps in the 90's. I have done it in my Marathon and also with the Liberty without the A/C's shutting down.

Now before you start throwing darts at me, if you were in the west and/or southwest at temps exceeding 100 degree's, I have no experience in that heat and do believe they would shut down due to overheating like Jon and others have stated. For those of us east of the big rocks, the cruiseairs are not a problem.

Let's hear from others that only have cruiseairs (gasp, no OTR) and get opinions based on actual facts and experience.

When mine shut down the outside temperatures were above 90, but not by much.

It was on our old bus which did not have radiator shutters. I think there will be a variation of experiences due to variations in the installation. As I recall the air to the Cruise Air condensing units on that bus has to enter the space behind the bumper through a series of slots across the opening. The bumper was solid, so air had to wind its way over and under the bumper to the slots and they were not that generous as I recall.

In retrospect I think the higher outside temps combined with a difficult air flow path, and limited open area for air to enter the Cruise Air compartment contributed to the issue. I think the air flow was actually impeded by the motion of the bus because when the bus was parked the Cruise Airs never shut down regardless of outside temps.

I don't know if we have to compare experiences as much as count the number of folks that have had problems to conclude for cooling while driving it is better to have roof airs.

I know it will create a huge debate, but I also think for comfort when driving we can also conclude the way to go is OTR, and if you cannot have OTR at least have roof airs with Cruise Airs being a distant third option.

I have no experience with what others call converter OTR so I do not know where to fit that into the pecking order of what's best. I do know if I had a coach with no OTR I would lie and tell the world how happy I am with whatever I have to keep it cool while driving. There is no sense trashing our own bus if we ever intend to sell it.

I tell you what Tom, I can't speak to the Cruiseair debate, but I can tell you that Austin is east of the big rocks and it is hotter'n hell here. 104 yesterday for about the 7th day in a row, and more of the same comin. Can't wait to get to the big rocks next month and cool off!

Quote:

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Originally Posted by truk4u

Joe,

You will have to define "very hot days." Two cruiseairs running off the inverters or gen, will in fact keep the bus comfortable on what I consider hot days, temps in the 90's. I have done it in my Marathon and also with the Liberty without the A/C's shutting down.

Now before you start throwing darts at me, if you were in the west and/or southwest at temps exceeding 100 degree's, I have no experience in that heat and do believe they would shut down due to overheating like Jon and others have stated. For those of us east of the big rocks, the cruiseairs are not a problem.

Let's hear from others that only have cruiseairs (gasp, no OTR) and get opinions based on actual facts and experience.

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Well, I can chime in here regarding a recent experience here in Florida where the temps have lately been in the mid to upper 90's.

We headed out of Port St. Lucie to spend a few days with friends last Thursday in Orlando and guess what..... no cold air from the OTR.... and it's in the low 90's :(

No problem dear.... we'll simply turn on the generator and crank up the CruiseAirs! Well..... as they say, not so fast.

I can tell you that in a 45' bus, in 90+ degree weather, driving down the highway that the CruiseAirs DO NOT DO THE JOB! Two shut down due to overheating within 30 minutes. If you like it toasty, you would have loved the ride.

But. there was also good news. Already being in Orlando, and in the spirit of spreading the wealth, we decided to head over to Parliament Coach to resolve our OTR problem. As suspected, low on refrigerant.

This was our first trip to Parliament Coach. Very good service experience. I owe a big "Thank You" to Rick May and his team for working tirelessly in sweltering heat to keep me and the missus cool:)

And when I say heat, the pavement temperature was measured at 140+:eek:

The ride home was so cold in the bus that Janice needed a sweatshirt..... there's NOTHING like Prevost factory OTR air conditioning.

We're back to being happy campers :D

Paul,

Does your frigidmobile have shutters?

Truk,

Yes, we have forward shutters.....and they default to open unless I close 'em, at least that's my understanding.

To be clear(?), the shutters are for the Cruise-Airs, two of which are behind the front bumper next to the electrical compartment below the driver's seat (on an H3, anyway). When traveling and using only the OTR, the shutters are to be closed. The OTR condensor is aft of the third bay (fourth bay), so the shutters do not do anything for the OTR. When parked and using the Cruise-Airs, the shutters should be opened to permit cooling air to circulate back to the Cruise-Air condensors. On our coach, the default is OPEN, and when they are closed, an indicator light/message is illuminated on the dash with the message 'shutters closed', which is the 'normal' mode of travel if using the OTR.

Trust me, please, when I say it is better to travel with the shutters closed (not use the Cruise-Airs), unless you want a million grasshopper, bee, butterfly carcasses wedged into the area behind the shutters, in the shutters, and up against the 2 front Cruise air housings and in the electrical compartment/steering arm bay. But if you do not have OTR, I realize you do what you have to do.

I know what they are for.

Our first coach did not have shutters. Of course Liberty had to provide for air flow to the Cruise Airs so behind the bumper there were ventilation slots.

We drove a lot in the winter and I can tell you that cold air would blow into the coach and your legs would freeze. I don't think the seated Prevost coach had openings so there would not be that cold air blowing in. I stuffed insulation in every opening inside the coach that I could find and the cold air still found a way to get in, but it was much less after my efforts to seal off the flow.

I'm sure those shutters are to close off the air flow in cold temperatures.

Closing the shutters while running the OTR air is something I haven't thought about, but makes sense.

I'll try it next time.

Thanks for the tip!

While at Joe's, we dropped the bumper and cleaned the Cruise Airs and the entire compartment. Now I'll be keeping my shutters closed while traveling. Nice thing ... when the ignition is off the shutters open, then close again when the ignition is on.

On the Marathon, does the "circulate fresh air" switch provide the same type function? I keep it closed to facilitate better OTR cooling when traveling but perhaps should open it when parked and using Cruiseairs if that is what it is for. My assumption was that it was like a car A/C with the re-circulate for maximum cooling option.

Ok, my Marathon doesn't have shutters. Thanks Steve........

Jon,

I noticed while looking behind the drop down bumper (this is on an H3, remember), trying to shovel out west Texas grasshopper corpses the size of rats, if I looked up but in front of the shutters, and on either side the slots, which are apparently for ventilation and lead to some ducting/pathway to somewhere, duct tape had been used and painted over to block them. I think your story fits into this somehow: maybe the ducts are for fresh air on coaches that do not have OTR, but this might be a bad guess.

Note: Our Liberty manual says the shutters should be closed when traveling and using the OTR. It says the shutters must be open when using the cruise-airs. With the (shutter) switch depressed (engaged), the shutters will close when the ignition is on.

Ken those ducts that are taped shut are the inlet for fresh air for the dash blowers. I too have them sealed up. In any season it lets the wrong temp air in.

Both my coaches had OTR, the first did not have shutters and the slots which admitted air to the Cruise Airs behind the bumper also let cold air spill into the driver's area. The current coach has shutters which default to the open position. When driving in cold temps, if I shut the shutters there is a significant reduction of cold air blowing across my legs.

I am sure all converters with Cruise Airs behind the bumper have air openings, but I don't know how many have shutters or a way to control air flow.

What I am curious about is how many with roof airs have no openings to the storage area behind the front bumper, and of those that have no openings, do they feel heat or cold blowing in from outside at the driver's area? I don't think Prevost intended for that area to receive outside air flow so once air gets into that area it finds its way into the dirver's area.

On mine, if the OAT is nice and I want fresh air only, opening the shutters makes a big difference in the amount of airflow to the vents. It's not enough of a flow to get air through the vents without the use of the blower, but it is a signficant improvment on volume.

Jon - Don't quite understand why your shutters would default to open while driving with OTR? I think most are opposite, including mine. Sure helps keep the road crap out of the compartment.

Paul - Not to drag out the OTR/Cruiseair debate, but if I have to run a couple cruiseairs while driving, I still have the full use of the dash air (which is working very well) and that may make the difference between roasting or not as you stated. All of this is providing the cruiseairs are running and not overheated of course.

Quote:

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Originally Posted by truk4u

Paul - Not to drag out the OTR/Cruiseair debate, but if I have to run a couple cruiseairs while driving, I still have the full use of the dash air (which is working very well) and that may make the difference between roasting or not as you stated. All of this is providing the cruiseairs are running and not overheated of course.

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I would think the biggest problem with OTR failure for the driver is lack of dash air. I could see it warming up quickly in that situation - even if the cruiseairs are working.

With our OTR air coach there is a rocker switch labeled AC or Heat. In the heat possition is the heat supplied by hot water heat from the engine solely or does the OTR compressor engage and supply heat from a heat pump mode?
Dumb question I know but I've never thought to check it out when I'm at the coach.

No Harry it is not a heat pump.

I know you will probably not need this info but for those who do need the heater if you still select a/c and then turn just the thermostat to warm the cabin the windows will defog much better verses going to the heat side of the selector.

Tom......I have no idea why on my coach and likely others of the vintage our shutters default to open. If I were to guess I would say to keep people from forgetting to open them when they run the Cruise Airs. I think Paul's coach has it right. They default to open and close when the ignition is on.

On OTR equipped coaches, at least on our 87, our 97 and apparently Harry's newer coach the system uses heated engine coolant to moderate the temps. If I set my thermostat to a cold position to cool the coach rapidly the heated engine coolant solenoid valve stays shut and air blowing across the evaporator coils of the AC is not heated at all. Once the coach starts to get cool and we want the temps inside the coach a little warmer, but still air conditioned we will see the "heat" annunciator light come on from time to time telling us the solenoid valve is opening letting coolant through the heat exchanger to warm up the cool air conditioned air a little before it blows into the coach.

The OTR AC system is powerful and it will have you wearing winter clothes unless you mix a little of the air conditioned air flow with some air heated up for that purpose. On newer model coaches I am not sure there is an indicator light to inform the driver that the air flow temps are being adjusted.

You have just described ours ,on our 85 chassis, to a tee.

When the heat light comes on you know your chillin:cool:

Had a quick look at my shutters = Open when the ignition is off and closes when coach is running and air is up.

Makes complete sense for a coach with OTR. I suppose mounting some sort of screen to keep the road toads out would defeat the purpose. Reduction of air flow by 50% by placing a screen.

On mine (no OTR A/C) the shutters come on automatically by some relay. They will even open and close while stopped ( key off). You can be sitting in the coach and hear them open and then close then open and close. No idea why.

GregM