OTR - Prevost Nashville

[Coloradobus]

Having just completed a 3400 mile trip from Colorado-Oshkosh-Elkhart(RV Hall of Fame)-Knoxville(Jon&Di's)-Prevost Nashville-Sedalia, Mo-Salinas, Ks, we will never know from this trip what OTR is like.

Yes, we have OTR in the Beaver, but by the time we got to Oshkosh it was cooling weakly. So last Wednesday 27th of July I called Nashville Prevost for a Monday morning appt-Aug 1st telling Keith in Service we are having OTR trouble and that we have an R-12 system. He tells me then, they have lots of R-12 and will scope the system out for leaks and faults.
We get there using our backup, Genset and 3 Cruise Airs, in the aweful heat as we left Knoxville for Goodlettesville Sunday afternoon July 31st.
Prevost identifies we have a leaky seal behind the compressor clutch the monring of aug 1st. Presto, new seal installed, only to be told they don't have R-12 to fill us up. They had given it to another customer that came last Friday the 29th after I had made our appointment 2 days prior.
Dsiappointment doesn't even touch the tip of this melting iceberg.
Now, they captured 5 pounds from our system before the repair, and would not credit us back a equivalent of 60 bucks a pouind they will invariably pump into to someone's elses system and charge them 60 bucks a pound for our 5 pounds. Rose in Service also told me they couldn't place it a To Go container, and what would the point be in putting the 5 pounds back into our system to yield no benefit?
Service told us, we could opt of changing fittings on the system and the dryer so they could fill us up with 24 pounds of R-134A, only to be told it will be less efficient in a system designed for R-12, will leak out and must be recharged each and every year here on. This just sucks!! I was so excited to get a full charge of R-12 in our OTR only to be told NO.
So we headed home 2 days ago from Nashville in 100+ degree heat with the genset trying to power our Cruise Airs to help keep us cool
Yesterday in Sedalia Missouri (Aug 2nd), it was 110-115, before and after lunch, the Cruise airs were screaming, the generator straining to almost red-hot and our coach interior was 98 degrrees. The dogs were lying in the kitchen on the tire floor, our water bay registered 118 degrees, and we were both sopping wet. All because Prevost Nashvilile, took our coach, fixed a seal, robbed us of what R-12 we had on board, and sent us out the door with no real A/C to travel 1300 miles in temps over 100 degrees.
We are home, the bus is parked, and I will be going to our more reliable Stewart and Stevenson to have our system charged like Prevost should have. Needless to say, we won't be going near Nashville for service again, unless we bring our own parts. I say this because the Parts dept didn't have a simple static discharge rubber strip in stock.
Nashville is truly a Palace, but from our experience its window-dressing.

[Jon Wehrenberg]

There are a couple of lessons from Jim's saga.

Over the years of ownership all of us are going to encounter issues with our AC systems. When we have a problem I have found out getting the problem resolved is more difficult than calling up the local AC repair man.

The first line of defense I have found is to be alert for potential issues. At the first sign a system does not have a wide spread between the cool air discharge and the return air intake some action should be required. You do not have to be an AC specialist and you do not need any equipment except for an IR temperature gun or two thermometers. At least once a year, preferably prior to the summer measure the discharge and return air and record the readings for every AC. Keep those readings because you not only want to know the information, you also want to add succeeding readings so you can spot changes to indicate a possible future problem. With multiple AC units you can compare their relative performance and a good AC technician can tweak the charge or make adjustments to the expansion valve to extract the best performance.

As an example if the cool air is blowing into the coach at 65 degrees, and the return air temp is 80 degrees you now have a reference point. You are concerned with the spread. Take the readings after the AC units have been running for a while and not after it has cycled of, but as the compressor is running.

If you have Cruise Airs you can poke your head in their mounting location and see a sight glass. If you want add what you see to the record. Typically if the CA is running right you will see some bubbles, but you could also see foaming, or clear liquid. You can have three or four CAs to compare so you should see a relationship between what you see in the sight glass and the temperature spread between discharge and return air. The bigger the spread the more efficient the unit is and you can relate that to what you see in the sight glass. A technician loves this kind of data.

If you have OTR the same temperature readings apply, but you can also take the temps at the suction side and the discharge side of the compressor. Again make sure the system has been run for a while (20 or 30 minutes). If you have an OTR system a good indicator of the proper charge without having gauges is to open the door on the passenger side and look at the lower sight glass in the receiver. The little red float should be in the center of the lower sight glass. That is the liquid level and if it is lower your system may be about to have a failure, and if it higher you may have too much Freon in the system, but without a system check you do not know if things are OK either way. There are other things besides Freon level that determine the system's health, but by recording this sight glass level it is another data point.

When looking at the receiver, if you have a vintage coach with the twin fans in the floor do not leave the condenser coil door open for more than a few seconds. If you have a vintage with the fans mounted to the condenser door you don't have to worry about how long the door is open.

If Jim's post doesn't wave a red flag about how important a good AC system is, nothing will. Consider high ambient temps, with driving into the sun, and no matter what you have it is going to struggle to overcome oppressive temps, and as the coach moves through the air it can be akin to heating a roast in a convection oven.

Some general comments about switching from R12 to 134A. The system must have its oil changed. The two types of refrigerant require different types of oil. A system flush is not a bad thing because AC oil is throughout the system. R12 is a more efficient refrigerant than 134A so when you make the switch some efficiency will be lost. 134A operates at higher pressures so if you are going to the expense of making the change consider replacing the expansion valve(s) and be alert to the fact that hoses and seals that might have worked fine on R12 may have to be replaced. 134A will find leaks not evident on a R12 charge.

Our OTR systems leak. Everybody involved in the design and production of the systems recognizes that and there is a standard as to what constitutes an acceptable loss rate. Because of this it is prudent to have a professional periodically check the health of the system and the refrigerant charge. Just because your 10 year old coach works fine today, it does not mean you have an acceptable volume of refrigerant. My guess is most of us tend to ignore our AC systems until the preformance is severly deficient, and we can actually monitor them and maintain them easily without AC equipment with a little effort. Don't forget the filters. And if John Klopp posts any information about AC units, pay attention. He is the guru.

[GDeen]

Wow - that is a horror story. 98 in the bus would have done our dog in.

Had my OTR serviced before our big trip at Prevost FW. Ours is a 134a system, and I had noticed some oil marks in the area of the compressor pulley and in the condensor bay around a couple of components. System calls for 24 lbs, and they vacuumed out 18 after 2 years since last service. Had a shaft seal replaced and found crimped wiring to the clutch coil in the process. Replaced that as well. System worked great on the trip (67 with 108 ambient).

I did watch over the tech's shoulder doing the work until about 9 PM. I know he was getting annoyed, but tough shit. I dogged him about the swap on new freon vs the recovered freon, and the total charge. After charging for a while and only showing 20 lbs of freon in the system, he was ready to call it a day. I asked about getting to 24lbs, and he said "we can get these things to cool a bus to 55 degrees in the summer, but this should be good enough." It wasn't for me and we kept working at it for a while longer to get more freon in the system.

[dreamchasers]

Having just completed a 3400 mile trip from Colorado-Oshkosh-Elkhart(RV Hall of Fame)-Knoxville(Jon&Di's)-Prevost Nashville-Sedalia, Mo-Salinas, Ks, we will never know from this trip what OTR is like.

Yes, we have OTR in the Beaver, but by the time we got to Oshkosh it was cooling weakly. So last Wednesday 27th of July I called Nashville Prevost for a Monday morning appt-Aug 1st telling Keith in Service we are having OTR trouble and that we have an R-12 system. He tells me then, they have lots of R-12 and will scope the system out for leaks and faults.
We get there using our backup, Genset and 3 Cruise Airs, in the aweful heat as we left Knoxville for Goodlettesville Sunday afternoon July 31st.
Prevost identifies we have a leaky seal behind the compressor clutch the monring of aug 1st. Presto, new seal installed, only to be told they don't have R-12 to fill us up. They had given it to another customer that came last Friday the 29th after I had made our appointment 2 days prior.
Dsiappointment doesn't even touch the tip of this melting iceberg.
Now, they captured 5 pounds from our system before the repair, and would not credit us back a equivalent of 60 bucks a pouind they will invariably pump into to someone's elses system and charge them 60 bucks a pound for our 5 pounds. Rose in Service also told me they couldn't place it a To Go container, and what would the point be in putting the 5 pounds back into our system to yield no benefit?
Service told us, we could opt of changing fittings on the system and the dryer so they could fill us up with 24 pounds of R-134A, only to be told it will be less efficient in a system designed for R-12, will leak out and must be recharged each and every year here on. This just sucks!! I was so excited to get a full charge of R-12 in our OTR only to be told NO.
So we headed home 2 days ago from Nashville in 100+ degree heat with the genset trying to power our Cruise Airs to help keep us cool
Yesterday in Sedalia Missouri (Aug 2nd), it was 110-115, before and after lunch, the Cruise airs were screaming, the generator straining to almost red-hot and our coach interior was 98 degrrees. The dogs were lying in the kitchen on the tire floor, our water bay registered 118 degrees, and we were both sopping wet. All because Prevost Nashvilile, took our coach, fixed a seal, robbed us of what R-12 we had on board, and sent us out the door with no real A/C to travel 1300 miles in temps over 100 degrees.
We are home, the bus is parked, and I will be going to our more reliable Stewart and Stevenson to have our system charged like Prevost should have. Needless to say, we won't be going near Nashville for service again, unless we bring our own parts. I say this because the Parts dept didn't have a simple static discharge rubber strip in stock.
Nashville is truly a Palace, but from our experience its window-dressing.

Colorado Bus,

As an R12 user, I share your grief with R12 dealings with Prevost. Also, as I looked into replacement of the R12 to R134A, the information I got was the same as yours, "it will not preform as well". Hummm, a unknown variable in my book.

I replace all the R12 hoses on my dash air with R134 barrier type, which is compatible with all refrigerants. After several failed attempts to find leaks at Prevost, I took the job on myself. It was simple, all the hose make up on my bus were replaceable. Meaning the fittings are designed to to be removed and replaced on new hoses. All the AC hose change out did not include the purchase of any new fittings. Only new hose. Also, most of the leaks were in the engine compartment. The heat the engine produces is an enemy of rubber and AC hoses are no exception. After replacement of hoses, I pressure checked with 250 PSI of nitrogen for 3 days to assure all current leaks were repaired. Then, I pulled a vacuum on the system and recharged with R12. The system has worked great since I rebuilt it.

I order my R12 from Ebay. The last 30 pound cylinder I purchased was $450. Not cheap, but available. You will need to get an HVAC license to purchase the freon. I got my license on line by taking a minor test.

When I started the process of getting my AC units to function properly, I was very discouraged by what Prevost Service Center had to say. I recall a quoted price of $6,000 back in 2007 to replace my R12 hoses on my dash air with the famous words that "it will not perform as well". A very chilling or in this case "non chilling" thought.

Do not despair over issues with your R12 AC, like I needlessly did. It is all manageable. You will need to take the time to deal with the issues or get someone else to do the same.

I am one that thinks Prevost Service Centers are not necessarily "the solution", but in some cases "the problem".

Colorado Bus, PM me with you contact information and I will call to chat. The R12 issue is not a big deal. You will simply need to have a few alternatives available.

I posted numerous pictures and details concerning the rebuilding of both of my AC systems. I have tried searching, but the search function does not work well for me. Perhaps some of the search gurus can find the posts.

Hector

[truk4u]

I feel the Bus Boy's pain, my dash A/C compressor gave it up today! Fortunately, roof airs work well and it wasn't a big deal. Trying to get repairs is another matter.

Called Panterra, sorry no parts, can't help.
Called Royal Phoenix, sorry, too busy can't help.
Called Prevost Nashville, see you when you get here, the compressor is on sale!

Two sides to every story...

Jim & Chris - I can snag you a 30 lb R-12 container by the time I come to Austin, they have been running about 250.00 in Atlanta. You would have a back up.

[CAPT MOGUL & Sandy]

Ed says, " we are not important anymore to them". At one time the motorhome was 35% of their business and now we are only 1% to them. We are now just PIA's to them. We don't matter!
Sorry to hear about your terrible experience, Chris&Jim.
That sounds like me having to experience Hell Hole Number 1, DETROIT, this week!

Help!!!

Sandy
Sandy

[merle&louise]

Sandy
Sandy,

What are you guys doing in Detroit?

[CAPT MOGUL & Sandy]

Left Petosky and Ed doesn't know how to drive South without going thru Detroit! As you remember, Ed sold his business of 47 yrs. and still is hoarding things to take back to Key west just to piss me off with junk!
He can't cut the cord!
Also, he has 3 children & grandchildren that still live here.
Tuga, do you think I wanted to vacation here? HA!
P.S. Tell ur daughter that my daughter,Amanda, is moving now to Italy with her hubby's new orders. I am so depressed over it. Just got them back here from Hawaii/Iraq.

[Coloradobus]

truk, let us know when you have found a 30 lb'er. I would be great to have back up. Just went over to the bus to get something out, and see that the rightside rear has sunk to the floor. So, now what did the hot weather do in? Always something, eh?
Got a note from a Robert Jones at Prevost who was going to send our concerns on for us. I was just emailing off their site.

[Jon Wehrenberg]

Jim/Chris, if it is any consolation the leans is not related to the AC issue. But when it rains it seems to pour.

I got to thinking about your circumstances and have come to the conclusion Prevost owes you some consideration. You went there based on their representation they had the materials to repair your R12 system. They were probably correct in replacing the compressor seal because that is likely the point where it leaked. How much it was leaking is unknown and every single OTR compressor has oil and dirt behind the clutch so you have to trust the judgment of the tech who declared the leak serious enough to require a new seal.

Where Prevost dropped the ball was in not tagging their supply of R12 as yours as soon as you made the appointment. Where they added insult to injury was in not restoring the R12 they removed back to the system. Now whoever is going to service the system has to pull a vacuum on it (again), leak check it (again) and then add the R12. Had the 5 pounds been put back in, the system would not have worked, but whoever was going to add R12 just had to add it without the added time consuming steps.

They should be compensated for the seal replacement, but I suspect the added time to vacuum the system and leak check it will offset the cost of the seal and replacement.

[Seabyrd]

Here is an ebay link for one that includes shipping.. I didn't realize it had gotten so high... I bought 2 30lb on Ebay several years ago for around $200 each and thought that was high.. these are $389 and free shipping and he says he has 10 available.

http://http://cgi.ebay.com/ebaymotors/Freeze-12-Refrigerant-R12-AC-Replacement-30lb-Cylinder-_W0QQcmdZViewItemQQhashZitem4cf6636b48QQitemZ33055 1225160QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries

Good Luck !!

[Seabyrd]

OOps that link didn't work.. I have to leave but will repost around 9 am sorry !!




Here is an ebay link for one that includes shipping.. I didn't realize it had gotten so high... I bought 2 30lb on Ebay several years ago for around $200 each and thought that was high.. these are $389 and free shipping and he says he has 10 available.

http://http://cgi.ebay.com/ebaymotors/Freeze-12-Refrigerant-R12-AC-Replacement-30lb-Cylinder-_W0QQcmdZViewItemQQhashZitem4cf6636b48QQitemZ33055 1225160QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries

Good Luck !!

[Coloradobus]

Jon, good point about the seal replacement. Ii fully expect to pay for what was repaired. The time involved in vaccuum testing the system, well, we will have to wait to see what the outcome is since I have raised quite a stink.
30 years ago, as a tour bus operator, we had to endure disfunctioning/ or weak A/C in the busses. Our 2001 CC 2 slide XL with CC over-the-raod cooling did a good jub aiding the dash air. Our 2002 Marathon XLII did OK with 2 Cruise Airs running on inverter plus the dash. The most recent past coach, 2000 Marathon H had the cruise airs channeled thru OTR ductwork (No OTR compressor) and did quite a very nice job keep the coach cool in at least 105 degrees in the Barstow area oce.
So, I was extremely excited about the Beaver's OTR capability with 109K btu of cooling in a 40 footer. I was hugely disappointed this trip. I didn't think we would have to endure roasting in our own bus.

[GDeen]

I am paying my dues for taunting Winchester from snowy Canada. We returned home to a torched compressor in our main living area. Now we are on a quick run to OK and my salon cruiseair took a dump. Tough times on the A/C units. Thank goodness for OTR.....

[Seabyrd]

Okay the ebay item number is 330551225160 . It goes off in 2 hrs but he has 10 or more available.
For some reason it wouldn't let me put in the full hyperlink to it.. may be because it was so long!? It kept cutting it short and wouldn't work... sorry about that.



OOps that link didn't work.. I have to leave but will repost around 9 am sorry !!

[mike kerley]

Prevost Service worked for me....

Just had service work done at Prevost Jacksonville and was very satisfied. They did some work that was not needed and utilized some parts not needed, but did not charge me for the parts or the time spent.

Changed both front windshields and gaskets (a tough job with new gaskets) and I am very pleased with the final product. They also worked on the speedo sender on the left front wheel and while at it changed 5 lug bolts that showed signs of thread damage.

They are not cheap, but did a good job and I believe I was fairly treated. I'll be back!

[jack14r]

I was at Prevost Jacksonville last week and they did a great job also,one item which I had an issue with since new was a slide fault code indication that they determined was caused by sawdust that had plugged up a drain and the moisture from rain would take days to dry up.They fixed it free and did 2 recall inspections also,I will also go back there again.

[Coloradobus]

I don't have a problem with Prevost Service Centers. We utilized them in the past and recently in Mira Loma. What I am peeved about being lured to Nashville under the pretense they had enough R-12 only to be told after repairs were made they didn't have it to re-charge our system completely.. I am sure some Entertainer Coach got the R-12 that was in stock when I called, and that our 5 pounds will be placed in someone else's system and be charged 60 dolllars a pound they quoted to us if they had. We were willing to pay for it at that time roughly $1,440.00, if they had had it. Guess they saved us money. But, boy was the trip home HOT.

[rahangman]

Trip home was HOT. We are about to leave Monument, CO to go home to N Arkansas and am considering driving at night and holing up in daytime at an RV Park either in Salinas or maybe Wichita

[Coloradobus]

Roger,

That sounds like a great idea. We considered it, but had to get home and back to work. We did stay at a KOA in Salina Ks Tuesday nite, just so we had power and let the genset cool off. It requires us to pull it out of the bay to check the oil and to add any if needed. Our single layer leather garden gloves were no match for keeping the hands proteceted from hot genset metal. It took 4 hours to get the bus interior down to where it nicer in than out, and the genset was still very warm the next morning..

[gmcbuffalo]

Jim and Chris is there by chance anything worry with your cooling system on the gen set?

[Coloradobus]

NO Coolant was fine, Oil was fine and radiator fans were turning, air blowing out from the bottom from the fans. Its just a hot one. enclosed in that bay/box. Seems OK. Only change to make, it we discovered we need to use Straight 30 weight oiil in it instead of multi wiehgt. A tech pointed that out since our venset is non-turbo'ed

[Jon Wehrenberg]

As a former aviator I would guess that every other pilot on here is very sensitive to the equipment we all flew. I was never able to prevent every equipment failure in-flight, but I probably was able to correct a lot by paying attention to what the plane was telling me. If a gauge was different by as little as a needle width I wanted to know why because it might be the first sign something is starting to fail.

I try to be as aware of clues that are forecasting a problem in the bus in the same way, but despite my best efforts there is so much going on in the bus I am not always succeessful. I posted earlier that if we take the time to measure our AC discharge and return air readings and record them we can probably predict when our AC systems need attention. Unfortunately we can spend hours gathering and recording data and stuff will still happen. This summer appears to have been a true test of our coach's AC systems. And when our AC systems are really needed none of us wants to find out they need service. Ditto with our generators, engines, etc.

But how many problems with AC systems as an example were predictable? My plane like a lot of others had a scanner or engine monitor. It had sensors which made it possible to read the cylinder head temperatures, exhaust gas temperatures, turbine inlet temperatures, etc. That information was available as the plane was flying and it could be downloiaded to a computer and displayed as raw data or as a graph. What was very important about the ability to have such data was that once a baseline was established, deviations from the norm could be used to diagnose or predict problems. There wasn't much going on in the plane that I did not know or have access to.

I am not going to outfit my coach with sensors and track the data from all the things in the coach. It would be information overload. But what everybody seems to be experiencing this summer with unanticipated AC problems might be avoided if I start making AC system data logging part of my routine maintenance. I will not be able to predict a compressor failure, but I should be able to identify a loss of refrigerant, dirty filters, and other changes that might be signs of an impending issue. Most of the problems we encounter with our AC systems seem to be related to loss of refrigerant or dirty filters, with motor problems lagging somewhere behind in terms of frequency.

So as soon as I can I am going to create a data logging sheet to include with my regular service to see if AC system failures are predictable to a certain extent. I am not worried about data tracking on my engine or generator as much because most if not all the data is already available, including oil pressures, engine temps, voltage output, etc.

Who knows? Maybe if this turns out to be worthwhile, future coaches can be set up with displays or data logging capability to make this information available so we all can predict low refrigerant levels and get them adjusted when we don't need our AC systems.

[truk4u]

Aviation habits are hard to break, such as gauge scan and can immediately identify a problem. Yesterday when my A/C compressor locked up, I picked up on the problem even before the cooling stopped. My engine and tranny gauges always read 15 -20 degree's less when the A/C is running due to the engine fan running on high. As soon as I saw the temps change, I knew there was a problem and soon after, things started getting warm in the bus. I stopped shortly after and the A/C belt was smoking since the compressor was locked up. Cut off the belt, start the gen and went on our way.

So, scan those gauges often. What about installing a digital thermostat on the intake and output of your A/C and then you can watch the difference in temps and learn what is normal. I have one in my inverter bay and generator bay so I can see the temps on one gauge. Is that overkill, maybe, but nice to know whats normal.

[Jon Wehrenberg]

That's exactly the kind of data point that is needed, but a snapshot is not sufficient. We need all the data on a continuing basis so we can see variations. This type of information is available to a very limited extent on multiplex coaches because with the multiplex message center the OTR high side and low side system pressures can be monitored.

I presume there are devices which will enable numerous inputs to be monitored and even downloaded for analysis. It is not much of a stretch to envision this on future multiplex coaches. I do not know if the multiplex system can or will store data for analysis, but I do know once a benchmark is established it would be possible to generate a fault code if some parameters are not met.

I suspect if a person was willing to go to the expense such a capability could easily be retrofitted to all existing coaches and there is probably no limit to the number of things such a system could monitor. In case this sounds too futuristic it is not. Our cars can display a lot of information now and tell us when all sorts of things require attention from tire pressures to engine temps to oil pressure. I am not familiar with Silver leaf but it sounds like that is the exact type of platform that is needed to pull all this together. If we can warn our holding tanks are full or our engine parameters are exceeded we already have the tools.

[johnklopp]

Jon has pointed out what is currently being done on many mission critical systems for military and commercial aircraft applications. While it would be nice to have real time data with air conditioning logging on the bus, it probably would become data overload for the majority of users. Just look at the Pro Driver on you coach; it does virtually the same thing but is dedicated to the engine and makes adjustments or shuts down the engine for you.

Gulfstream aircraft systems currently in use monitor critical and non-critical system data and will send an automatic signal to the closest MRO or maintenance repair organization recommending adjustments, repairs or replacement of components. Gulfstream even goes as far as dispatching the required part before the aircraft has landed. Prevost would love this but you might not.

In the bus world only a little data needs to be collected to predict with a high degree of probability that a failure or problem will soon occur. Using the example Jon pointed out; taking differential temperature across the intake and supply ducts will give you an idea of system performance. Adding a few more readings will give you additional predictive data. Once you know the typical differential temperatures you will be able to see a trend indicating on going performance to be used as a base line. Just because the delta is increasing doesn’t mean you have more cooling capacity. The likely problem is a dirty evaporator air filter reducing the air flow etc.

In addition to Jon’s recommendation to look at the liquid receiver to see the refrigerant level on the sight glass, use your infrared thermometer to record the refrigerant temperature in the receiver. It will change with the ambient temperature but the delta between the OAT and the refrigerant should stay roughly the same. If the delta increases, there is a high probability that you have a dirty condenser coil etc.

[Woody]

Question

Since we had our OTR overhauled we have not used it - today with the temp of 75 out and 85 in we turned it on while driving for about a half hour - it got cool but certainly not cold.

How long sholuld it take to get the temps you all talk about?

[Jon Wehrenberg]

OTR brings the inside temps down fairly quick which means absolutely nothing because the answer is not definitive. If I were to question the effectiveness of my OTR one of the first things I would do is get my temperature gun and measure the temperature at a discharge point such as where the air blows from the window sills. I would then find where the air return for the coach is and measure the return air temperature.

The difference between those two temperatures is a good indication of the performance of the AC and this applies to any AC unit.

If I saw a temperature spread of 15 degrees I would consider the AC to be working. Keep in mind that is not necessarily the correct temperature spread for a well performing AC system or unit. In order to determine using the IR temperature gun as my only tool if the system is working properly I would have to have a series of temperature readings spread over time to know if that is indicating the system works well or if it is showing signs of reduced performance.

There are a lot of things that have to be looked at to determine the health of your OTR, but most of them require gauges or the knowledge of the system a professional would possess.

A few general comments however. First, if the entire coach is heat soaked it is going to take a while for the OTR system or the Cruise Airs to absorb that heat. You can help by making sure the return air filters are clean so you are getting the maximum air flow. A second thing to do is to verify the valve (that is used to mix the heat from the coolant with the cooled air to temper the air when you adjust the temperature knob up) is closing and you are not getting hot coolant flowing through the heat exchanger offsetting the efforts of the AC system. That valve is in the evaporator bay and you should not feel any heat on the piping.

I assume you are driving the bus or at least running on high idle when you express concern about the performance. A well performing OTR system is going to get a coach so cold you will be wearing sweaters and the outside of the windows will be sweating if it is working. But how long it takes to get to that point is dependent upon a lot of factors so I doubt if any one can give an accurate estimate of how long that will be.

[phorner]

As Jon mentioned, a well performing OTR system can make your teeth chatter.

Another tip is to check the outside air intake flap valve located in the evaporator bay. The OTR system draws air from both inside the bus as well as outside via flexible ducting attached to the evaporator bay door. There is a manual flap valve in that ducting which can be closed, thereby limiting the amount of "outside" air being drawn in. By maximizing the return air supply from inside the bus, I have noticed that my OTR will cool the interior at a somewhat faster pace, but ultimately it depends on how heat soaked the bus is to start with.

Once the bus has cooled down, it seems to continually decrease in temperature as you continue to cool primarily interior air which is now cool to start with.

At least that's how it worked for me...

[johnklopp]

I’m not sure exactly what overhauled means. At the minimum it may have been a major service with belt and seal replacement. Whatever the case may be its important to run an open drive compressor at least monthly for 15 min or so. The reason is periodic lubrication of the shaft seal located behind the clutch on the compressor. If the compressor is properly cared for with all of the high and low pressure safeties operational your open drive compressor air conditioning systems should run several years without problems.
Compressors should be just as dependable as they are in your home air conditioning system or your late model car. A compressor is similar to an engine with cylinders and an oil sump. Rooftop electric compressors will typically be rotary rather than reciprocating. The bottom line is they are dependable and 99% of the time fail for external causes that could have or should have been preventable.

Typical preventable compressor failures include the following:

Los of oil and refrigerant. If you have a refrigerant leak you also have an oil leak since the oil is entrained with the refrigerant and circulates thru the entire system. Many leaks are found by locating oil at connection points or shaft seals. The oil may not be apparent but the collection of dust on the oil leak is a dead giveaway.

Oil needs to be added carefully. The open drive compressor on OTR air will have a sight glass were you can see the oil level. Just because the oil is at the bottom of the sight glass doesn’t mean its low. The oil needs to be checked after the system has operated half an hour or more at high load. The reason is that the compressor has unloaders that reduce the refrigerant mass flow at light loads. Oil will tend to collect in some areas of the system and lower the oil level in the compressor. When the load returns to high, the additional mass flow of the refrigerant will return the missing oil to the compressor. If someone has added oil to a system that is not low, the cooling capacity will be reduced. The reason is the additional percentage of oil in the entrained refrigerant will insulate the refrigerant from the coils and reduce heat transfer. I’m probably getting close to information overload so I will leave it at that.

Florescent dye is commonly used by technicians in the search for leaks. It is easily added to an operational system and allows a technician with an ultraviolet flashlight to see tiny leaks that now glow in the flashlight beam. You can purchase a portable florescent leak detection kit made by “yellow jacket” at most refrigerant supply stores.

High discharge pressure caused by a dirty condenser coil will increase the compressor discharge pressure. In the short term the affect will be reduction in cooling capacity and a substantial increase in power to drive or run the compressor.

If the compressor is for OTR air, the unloaders seals life will be reduced. If a technician ever indicates your compressor is worn out, ask him to do maintenance on it. The unloaders seals, shaft seals, cylinder liners etc. are all replicable. If he doesn’t have the knowledge, purchase a rebuilt unit from one of many companies that remanufacture the Carrier open drive bus compressors. You should be able to get one complete with a new clutch for less than $2000.

If the compressor is an electrically driven roof mount or bay mount, your compressor can not be rebuilt. The damage that will occur is a breakdown of the motor windings. Eventually the motor will fail.

Dirty evaporator filters will cause the refrigerant to have an incomplete phase change from liquid to gas. If it’s bad enough some liquid refrigerants will get back to the compressor. Since liquid doesn’t compress, the compressors valves will break.

Eclectic compressor short cycling will cause motor winding failure due to lack of cooling. You electric compressor should have a short cycle time delay. If it’s been removed or the time interval has been changed overheating and premature failure will result. The reason is your electric compressor is cooled by return refrigerant gas. Each time a compressor is started a large amount of power is used to overcome static friction and then increase the motor to operational speed. This puts residual heat into the motor that takes around 5 minutes of normal operation to remove. No or very low cooling is taking place while the compressor is off. Repetitive short cycling of the compressor will progressively heat the motor winding until a failure occurs.

This represents a partial summary of the preventable failures that your air conditioners are experiencing.

Its time for an adult beverage

[Woody]

Thank you all.

The high temp today will be 65F so it will be a while before I can test temps etc.

By overhaul i meant changing most all hoses, dryer, oil and belt - the system never worked before we did this (there was a bad hose) and now does.

[gmcbuffalo]

anyone have a picture of the "valve" Jon speaks of in the evaporator bay?

[Jon Wehrenberg]

The evaporator bay has changed over the years so the valve location and type is going to vary. It is a solenoid valve on the cooling system line going to the heat exchanger in the OTR evaporator compartment. The heat exchanger and the evaporator coil are sandwiched together and the only time coolant should flow through the valve is when you require heat in the coach, or when you need to temper the cooling air of the AC system. If you don't have OTR none of this applies.

[gmcbuffalo]

Jon your round tires "sig" reminds me of the time I plowed two furrows in a gravel parking lot for about 100'.

[GDeen]

We were in OK over the weekend, and are down the middle cruiseair in our Marathon as of Thursday evening. By late Friday afternoon, ambient temps were 111 F in the shade, and we weren't parked in the shade.

At 5:00 temps were increasing in the bus and the rear CA begin cycling off on high pressure. The sun was beating down on the rear of the bus and hot wind was blowing the condensor discharge back on itself. Temps begin escalating quickly with only the front CA running. In the Marathon design, the front CA is the least efficient so we were going downhill quickly.

Time to make a change. Fired up the engine on high idle, and ran the OTR. Brought interior temps down from near 90 to mid 70's in about 20-30 minutes. By sundown the outside temps were around 105, and the 2 remaining CA's could keep up given the head start the OTR gave them.

Saturday, round 2. Ran the OTR from 12 to 6 all afternoon. Ambient temps again above 110. Interior temps - salon area was in the mid 60's and the front and rear of the bus were around 70. Could have run the front down lower by running the driver blower on high but there was no need. Fortunately the "park" we were in was fairly deserted so the noise wasn't noticed or complained about.

BTW, I burned 1.17 gph on high idle with the OTR running. Best $30 I have ever spent on Saturday afternoon.

AAP shipped me a new CA compressor this morning.

[merle&louise]

Great post Gordo..... If that doesn't make an OTR believer out of the skeptics I don't know what will !!!!!

I sure wish I had it in my coach. There is nothing like redundancy in AC systems.

Remind me to park next to you at POG 10 - just in case we get a heat wave!

[Danss]

As you know Tuga, I have 4 roof top air cond on my bus and just returned from a 3 week trip up to Michigan and Wisc. Of course it was cool there but extremely hot going up and back thru MS., TN. KY, IL, AR, IN, MO, AL and on the road never ran anything but Dash air and one roof top unit off of the invertor and never had problem with heat. When parked at night ran only 2 roof top units. I am happy with performance and the fact that they can be replaced so cheap. No problems to date after 11 years.

[Jon Wehrenberg]

Must be a southern thing Dan. What you consider heat and what I consider heat might be two different things. When I visited my aunt and uncle in FL they would not turn on the AC in their house until it got to 85 degrees inside the house.

By then I was gasping for air and trying to dial 911.

But when they get down to 75 in the house they are walking around with winter coats on.

[Danss]

It was cool enough with me wearing a t-shirt, but I am sure I would not be as happy running in West Tx , az., NM but you can probaly guess that I am not going to try it!!! Sold my first Bus with 3 cruise airs and delivered to Flagstaff because it was much cooler than Phoenix.If I were traveling a lot in the very hot states I am sure the OTR would be very desireable, however I am just a poor redneck from MS and cannot afford the fuel to go that far!!

[truk4u]

I'll bet if Gordon had roof airs, the outcome would have been much better. The roof airs don't shut down like the CA's. We just finished up a month of travel with the worst ambient temp of 101 and most of the time running was in the 90's. All we needed for most of the trip was the dash and the 2nd overhead evaporator running and only had to fire the gen with the roof airs one day while getting through the Chicago area at 101.

With the extreme temps Gordon experienced, OTR would be a must.

[rfoster]

Gordon: When the temps were the highest, did you look outside and see a big guy that looked like Winchester holding a pitchfork?

[GDeen]

Tom, I have never experienced CA shut down before. We have been in 107 before with no problem, but all 3 were working. With only 2 CA's working and ambient temps over 110, we started a downward spiral. The OTR was a life saver in this case for sure.

Roger - all 6'6" of him, except he was orange instead of red.

Dan - you Mississippi boys are used to the delta heat and love it that way.

[Neal&Carla]

This thread started about how terrible Prevost Nashville was for not having R-12available. Jon has for years has told us how bad it is to have Prevost work on our buses. If the seals and R-12 are so easy to fix why did not Jon do the work for Colorado Bus in Knoxville. Since we have been part of POG, Jon has bashed all Country Couch buses as inferior and any bus with slides or without OTR as not desirable. Now Jon talks about about how good new technology and slides are. I have not owned a bus with Cruise Airs but Cruise Airs seem to be the inferior product rather than OTR being superior.

[Coloradobus]

Neal and Carla, Whoa, cool your jets and seek out dry cheerios!!.

We went to Prevost and Nashville for a couple reasons. One, of course was to get the OTR sorted. We visited the Wehrenbergs for their hospitality and friendship. Thanks to Jon and Di, we have a greater understanding of the Great Smokies area. We are big boys and deal with our repairs. We could have replaced the seal ourselves providing we had the RoBinAir machine to evacuate what Freon R-12 was still in the system and the nitrogen to charge the system to 250 psi for the leak check. and the RobinAir machine to add the new freon R-12 after pulling a vaccuum to remove the nitrogen and anything else in the system once the clutch pulley seal was renewed.. We could have done all this when we got home and gone to the shop we use.. But we didn't, nor did we have the time to do the repair if we had all the equpment. We weren't carting around enough spare change to go to Harbor Frieight and buy it, the best option was Prevost. We do service visits at Prevost Ca several times a year. Sure, I could change our oil, or tranny fluid at home, but what DO you DO with the used fluids. AutoZone frowns upon a customer bringing in 10 gallons of oil from a Change all at the same time.. I know, I tried once.

We have had 3 Prevost Conversions equipped with Cruise Airs and one with rooftops. Our first bus was a 2001 Country Coach XL 45 ('99 Shell) with slides had 4 rooftop units. We had no qualms about roof airs! They certainly are easier and less costly to replace or repair. The CC had rooftops, and the next coach had Cruise Airs, later on personally we just like them. We don't require under bay storage where we could transport the contents of the Biltmore.

My biggest gripe that precipated this thread was the fact having made the appoinment 6 days in advance of our arrival and Nashville falling short., During my call I had indicated that our coach had an R-12 Freon system on board, and I was assured Nashville had enough R-12, (24 pounds) to completely refill our system once deemed leak-free. Between my appointment call (7-25-2011) and our arrival (Aug 1st), the R-12 they had instock was used for someone elses needs, with no re-order for us. That's what this was about, nothing more.
Mostlly, reading all these threads is time consuming yet informative, so much so most of us have gleaned information, whether we do the work ourselves or not for whatever the reason, time, location, available equipment etc, we have knowledge to intelligently watch our coach's backside..
No one is bashing one converter over another, it has been in jest in the past. Just ask Fast Roger. Heck, if you want, pm me and I will tell you a hair-rasing story about our XLII!!..and it wasn't a Country Coach!! Every bus out there has its issues whether someone is wililng to admit it. Man built the bus, and the bus will break!!

The newest Prevost techmology is a tremendous step forward to aiding the owner/driver's knowledge of the bus. Being informed is the most important thing when it comes to the operation and maintenance and safety of our coaches. The new Multi-plex system does just that, it INFORMS.
Some on this forum who are great people and great friends enjoy working on their busses exclusively. We do some, but the really big stuff we hire out. Its about pacticality and efficientcy, and having this resource to float a quesiton about a particular item of interest.

As memtioned, we have gone to other Prevost service centers with glowing results. But I feel the point to be made, there are other service operations that work on Prevosts who are competitive to Prevost and dont require a special 1000 mile trip to get to them. If our OTR issue had cropped up before we took our trip, I would have dealt with it locally.
In our case, we drive 12 miles to Stewart and Stevenson. I just bet someone out there has an "S and S" horror story. None are perfect, we were caught with our guard down, and didn't ask the necessary questions to CYA when we had our appointment.
We were hot, and were hoping for "instant cool" altho the final outcome with R-12 if Prevost had it, would have been very spendy after the appointment. It was a lesson learned.
By the way Prevost did right by us when the bill arrived yesterday.

[Jon Wehrenberg]

This thread started about how terrible Prevost Nashville was for not having R-12available. Jon has for years has told us how bad it is to have Prevost work on our buses. If the seals and R-12 are so easy to fix why did not Jon do the work for Colorado Bus in Knoxville. Since we have been part of POG, Jon has bashed all Country Couch buses as inferior and any bus with slides or without OTR as not desirable. Now Jon talks about about how good new technology and slides are. I have not owned a bus with Cruise Airs but Cruise Airs seem to be the inferior product rather than OTR being superior.

Here's my response in case anyone is interested.....At one time Prevost was the standard by which I measured every other business. Prevost was that good. Di and I had never had service and customer support the equal of that which was provided by Prevost and Liberty. However things changed with Prevost. It wasn't an instant change, but over time more and more Prevost owners reported on this forum and P-Stuff how they were overcharged or experienced poor quality work. A few examples were a customer who was quoted about $7000 for slide repairs, and ended up with a bill for $14,000. Another customer who needed a hub seal replacement went back 3 or 4 times before it was made right, and part of the repair was an axle replacement due to the original being damaged by the technician. For a while a number of owners who experienced the leans got the soapy water treatment. They paid for hours and hours of a technician's time while he spent time spraying the underside of the coach to find out why the coach leaned. More than one owner was quoted more than $4000 dollars for air bag replacement when we know air bags cost about $1200 or less and the labor is about 10 hours. My point is that Prevost still possesses the greatest expertise when our coaches need service, but every owner needs to be very aware that expertise has at times been sproradic and the best approach is to get quotes, know and understand the coach, and regardless of who does the work, to follow Ken Z's practice of documenting everything so if there is a problem with the bill you have the data.

As a Liberty owner I will continue to bust the balls of owners of every other conversion. That's just the way it is. Having said that however I recognize that my coach as produced by Liberty has features that might not equal those of some other conversions. I think my former Liberty had a Cruise Air installation that was not equal to my current bus. They shut down when I tried to use them on a heat soaked highway. On my current bus I think that problem is gone. I really like the way Marathon does their plumbing bay. I wish my coach had a water manifold insteasd of shut off valves hidden inside or behind cabinetry. Country Coach has in our opinion some of the nicest interiors and floor plans in the industry. There was a CC at the first Kerrville rally that we really liked because it was so well done and laid out so well. We both think Liberty is more over the top with their decor, but we have gotten to like ours because it is different than how we live and who we are. But what's the sense of having an ornate interior if we cannot pick on people who drive coaches with equally well done interiors. But I DO have issues with CC. When Ray Davis first joined POG and had his new-to-him CC (which was a great looking coach) they treated him like dirt and pushed him off when he needed service. If I recall he got an appointment for repairs six months down the road. That was inexcusable. If he had a coach that did not have proprietary systems he could have shrugged it off and gone anywhere.

So now let's fast forward to what my thinking is regarding a new coach (which is not going to happen unless I pass a couple of very big hurdles). I think Prevost has the slides right. Until Prevost developed the current slide design there were many infancy problems with slides. With each generation they got better and much more reliable. That is not to say they are perfect because to get to this point a Prevost slide coach has had to have structural changes that affect the utility of the bays and they still have seals that have a rather short service life. But we aren't getting any younger and if we intend to upgrade to a new coach it isn't going to be a no slide coach because that is what we have now (and really, really like). OTR is mentioned. Cruise Airs are mentioned. Apples and oranges. OTR is an AC and heating system used while the coach is being driven. There is nothing out there that is as good. That is not subject to debate. Prevost makes a 109,000 BTU (current capacity) system that will keep the coach occupants comfortable in any conditions on this planet. Cruise Airs and roof airs are a different story and in my mind are intended for keeping the coach comfortable while the coach is parked. They each have their advantages and right now, with the new bay layout available on the X3-45 roof airs are likely the AC of choice for too many reasons to go into here.

The new Prevost buses are amazing. The multiplex system is so logical, offers so much benefits such as reducing wiring and devices such as relays and circuit breakers by as much as 30%. The multiplex is a powerful diagnostic tool and with the message center there is not much a driver has to guess at. The system provides information our older coaches require computers or diagnostic equipment to access. But it goes further. The new coaches have adaptive braking, stability control, and a Volvo engine that brings back some of the mileage lost with the EGR engines. Are they exactly what I want? No. I cannot get a solid front axle or long range fuel, but the benefits in other areas makes the overall coach a huge step up from what I am driving right now.

As to working on Chris and Jim's bus that was their call and they had already scheduled service at Nashville by the time they visited. We got together to visit and enjoy each other's company. I would have gladly jumped into the problem if they asked, but they did not. Also I don't have a new seal kit for the compressor, I don't have R-12, and we just never discussed a repair because they got here late Friday and during the weekend I would have had no access to parts or supplies anyway. I like working on buses, but I hope that is not always why folks come to visit.

If you want to go into greater detail on any of this, let me know. Keep in mind however we are all entitled to opinions and as one who has not been shy about offering opinions I do not feel bad when asked to defend mine. Or change my opinions.

[truk4u]

This POG bunch is a class act! Neal's post was answered in a logical gentlemen's manner and not subject to the flaming, rock throwing crap you see on almost every other forum.

This is exactly what sets this forum and group aside from the others.

[michaeldterry]

This POG bunch is a class act! Neal's post was answered in a logical gentlemen's manner and not subject to the flaming, rock throwing crap you see on almost every other forum.

This is exactly what sets this forum and group aside from the others.

What Tom said!

[Gary & Peggy Stevens]

Tom your post was SPOT ON, and I think everybody on this forum as the same appreciation for the answers provided to Neal, from Jim / Chris and Jon. Great job guys.

Gary S.

[Danss]

I believe that Jon has as much or more knowledge about all these Buses than anyone else in the country! He would be the 1st person I would call if I had a serious problem. This is one of the most informative and nices group that I have had the opportunity to be associated with. Lets bury all this and all go to Austin!!

[Alek&Lucia]

Just because of very mature posts like that POG is still rated AAA and no chances to be downgraded to AA+ or less :p

Alek

[Kenneth Brewer]

This POG bunch is a class act! Neal's post was answered in a logical gentlemen's manner and not subject to the flaming, rock throwing crap you see on almost every other forum.

This is exactly what sets this forum and group aside from the others.

If only Congress communicated internally as well as this forum.

[Neal&Carla]

Jon. I would have never replied had your post to Dan not implied you are the only one who can judge cool or comfort.

Coloradro. You blasted Prevost Nashville in the start of this post but note they try to correct it at the very end of a long dissertation about how bad I was to question you or Jon.

If you check our previous posts you can find an absolute mess with our bus and Stewart and Stevenson.

We had such a positive experience with Prevost Nashville on a non scheduled basis in March that when we realized we needed more service we altered vacation plans to have service finished there yesterday. We were extremely pleased by the service again.
Neal

[phorner]

Just because of very mature posts like that POG is still rated AAA and no chances to be downgraded to AA+ or less :p

Alek

Man.......never thought I'd see the day when "very mature" and "POG" would be used in the same sentence :cool:

[Coloradobus]

Neal and Carla,
I never like hearing about bad experiences but I knew there could be an S&S story. No sense beating a dead horse over and over, we experienced disappointment and have moved on. The Denver area has R-12 available at reasonable prices. I have a standing appt at our S & S to fill 'er up, As I said a few posts back,we didn't do our CYA's upon arrival. The old shouda, coulda, woulda applies here about making sure there was R-12 available at Nashville once we were on site, but we didn't. Our bill that was emailed was satisfactory, so the story should end.

[Jon Wehrenberg]

Jon. I would have never replied had your post to Dan not implied you are the only one who can judge cool or comfort.

Neal

Neal,

If my words suggested I was the only one who could judge cool or comfort I need to restate my intent. I AM the only one who can judge my cool or comfort. I thought I stated that others may feel comfortable at 85 or some such temperature, but I begin to get comfortable as the temps start dropping through 70F. That is why for a lot of folks a 45 foot coach with slides and one AC working is fine, but subject me to a coach like that with outside temps at 90 or above and I would have heat stroke. I'm still a northern boy.

Regardless of what temperature any of us deems comfortable, for me the bottom line is I need OTR for a variety of reasons.

[Gary & Peggy Stevens]

Neil and Carla are great people. I'll never forget how Peg and I met them the first time @ Rayford RV Resort in the Woodlands, TX. I'll bet Neal & Carla won't forget it either ?? !


Gary S.

[Jon Wehrenberg]

I'm not surprised you all (a southern phrase) got along. They saw your Country Coach bumper stickers.

[phorner]

I surely don't want to rekindle the flames of the pro/con argument regarding Prevost OTR air conditioning.

However.....

I just drove across Florida from Port Saint Lucie to the Tampa area in the middle of the day, a trip of a little more than 3 hours. Even though it doesn't match the searing heat of the desert south west during the summer, central Florida in August with temps in the mid-90's and what feels like 90% humidity, will get your attention.

Now I'm sure that other buses with alternative air conditioning systems can be comfortable on a day like this, but, if you have never driven under these conditions in an OTR equipped bus, you owe it to yourself to experience it.

The cooling capacity is simply incredible.

[Coloradobus]

A Follow UP.

Got a call from the Prevost Nashville Service Mgr, Mike Fitch apologizing for dropping the ball with regard to stocking R-12 for our visit. I told him we were satisfied with the bill as first emailed, but he offered to resubmit it to us less the total labor cost for our inconvenience and for us to cover the parts involved in the repair. I told Mike we wern't looking for any concessions, but we will incur more cost at Stewart and Stevenson to recharge the OTR to complete the job. So, we agreed with Mike to split the difference in the labor charge to help offset what we will be charged at "S" and "S" locally. I wasn't expecting anything other than contact acknowledging our disappointment, so this was a nice surprise. Thank you Prevost Nashville Mike Fitch.

[Mark3101]

Sure is nice when they step up and try to make things right. I have been very satisfied with the people at the TN branch. If there has been any question about a bill, they are very good at either explaining it better, or adjusting it to my satisfaction.

I just hope S & S gets your OTR air working to your satisfaction. Sounds like you had a miserable trip home.