Sitting here in Minnesota in the dead of winter, I am trying figure out why my coach was so hot inside last summer. Its an MC-5 with 8" roof raise and Hehr RV style windows. Two 13,000 BTU roof units and a 7K Kohler generator. Bus air was removed by PO.
When we were parked, we had plenty of cool air but going down the road on 90 degree days, the two roof units barely would keep it 86 inside. How can I fix this problem? Would adding a driver's air (automotive style) help? Or do i need basement air? or is bus air the only way to really keep one of these things cool.
Fred
Hi Fred,
I would intice you to look into a dash system which runs off your engine.
Look in Red Dot's site or even call them, they are very helpfull with set-up information.
OTR engine A/C is going to be the only system powerfull enough to overcome the heat gain that
the wind and the sun creates while under way.
Good Luck
Nick-
Good information nick, we have that problem too, on the road the bus gets pretty warm inside, can you post the red dot site for us?
I open the windows, but watch the paper towels.
Bill
So if one purchased a bus with a fully functional OTR air system would it be beneficial to them to keep the system for use during driving. Then have a second system for while parked? I was considering removing the OTR system to get some funds for other projects, would this be a good idea?
Hi Guy,
Try this
http://www.rdac.com/Pages/product_pages/units_pages/5075_unit.html
or this
http://www.rdac.com/Pages/product_pages/units_pages/5040_unit.html
Nick-
If the temps are high it's very difficult, if not impossible, for the roof air(s) to keep the coach comfortably cool. Just too much heat in through the front windshield.
The front roof AC can be run of course by the generator, or a systems which allows the AC to be run though the Inverter and the big engine alternator/generator recharges the batts while going down the road, faster than the front AC can run them down.
Some people place a temp barrier directly behind the front air, such as a sheet or blanket. The sheet is hung from the roof and stretched from wall to wall. Works so well for some, they use it all the time during high temps.
If nothing else it will give some comfort till you decide "your way" for permanent.
I realize maintaining an OTR system, getting it to work in the first place, can be expensive. The general suggestion for converters is to remove the OTR air. I kept mine, and it works great, but I do have to add R134a each year. How cool do buses that rely on 2 or 3 roof units really stay on a hot day, driving down the road, facing the sun? Even a couple pounds low on refrigerant my OTR air will freeze the front 2/3's of the bus (the back 1/3 is comfy) on a hot July day in Georgia on the interstate. I didn't even use the dash air. Maybe my system's down in capacity (5-6 tons?) with the low refrigerant, but I can't imagine being cool enough with a couple of roof units.
I also suggest something that runs off the engine. I've seen some nice units (Red Dot, I believe) that look like they would fit above the windshield if one has a raised roof. If not, I'm sure something could be mounted in the spare tire bay and ducted upwards... it would likely be lots quieter than a system mounted in the factory location in the dash or anywhere in the bus itself. Another possibility would be a mini split, although not meant for vehicles, with the inside section mounted above the windshield or on the side right behind the driver. A 12,000 btu unit will run off 120 volts. If your generator is set up for 240 volts, you could use a 18,000 btu model. I suppose the easiest option, though, would be another roof unit (15,000 btu) mounted close to the front and ducted to right above the driver to cool the area heated by sun on the windshield. Good luck with it. Let us know what you decide to do. Being hot and driving for hours really sucks.
David
I made up my own system for my 4106, two 22500 btu evaporators, one in dash one half way back mounted in dinette seat, one condenser and a jap compresser, never run the roof air on the road, no need, these are small sized street rod evaporators but pack a pretty good punch. one of the best things i ever did to my bus
Frank Allen
kingfa39,
where did you get the stuff? took out my OTR air and have regretted it ever since. except for the genset space I gained.
Devin
Assuming the OTR system is gone and the gen set is now where the condenser was. You want to put in a dash air unit. Where do you put the condenser? The former AC lines to the engine compartment are now full of wires. Where do you run the new lines? I have a MC7 BTW. Suggestions?
TOM
Quote from: oldmansax on February 02, 2008, 02:03:02 PM
Assuming the OTR system is gone and the gen set is now where the condenser was. You want to put in a dash air unit. Where do you put the condenser? The former AC lines to the engine compartment are now full of wires. Where do you run the new lines? I have a MC7 BTW. Suggestions?
TOM
Hi Tom,
Behind one or both of your engine radiators is a good spot.
Nick-
I have a 40 x 102 transit with very large single pane windows with a light tint. I also have 2" of sprayed in insulation in the walls and ceilings (nothing under the floor except my carpet with pad). Last summer coming through mojave desert, it was 107 degrees and with the two front A/C's running (have three) was a comfortable 76 degrees inside while driving. I also have a dash fan that blows air in my face that works well.
I think that instead of looking to add more A/C (those two roof tops should freeze you out of a 35 ft'r) you should look into insulating the bus better and look for air leaks going down the road that lets hot air in. Good Luck, TomC
I installed a Red Dot 5045 and it is a great unit. It is rated at 46K BTU heating and 33K cooling. Think about it, that is more than two roof airs!
It fit very nicely under my new dash. I have attached a photo that sort of shows the installation.
The unit has a cable controlled flapper that diverts the air flow from the front four fully adjustable outlets to the back opening. On the back I made a plate with 4 outlets that connect to the defroster outlet hoses.
I plumbed the heater to my AquaHot and that really makes a really nice setup. This morning is was a bit cool, so I fired up the Red Dot and had great heat flowing towards the passenger seat where I was sitting. I can defrost the windows without even starting the engine! The heat going down the road has been sufficient for any condition we have encountered (have been in Zero degree weather) while going down the road
The AC is absolutely great and can handle most any condition we have encountered except heading west in the late afternoon on a hot day and even then it makes the drive bearable. My bus is not well insulated and still has some air leaks that I am working on.
Jim
OTR A/C is on the bottom of my "I'll get to it someday" list. Mostly due to money, but in part because I want to get the engine rock solid first and the interior mostly done. I still have some fairly minor oil leaks on my Series 60 I need to fix.
On my bus it would be pretty well impossible to place the condenser behind the radiator. With the cooling issues inherent to most buses would it be a good idea place the condenser in front of the radiator like modern cars?
I've been considering a rooftop condenser like Van Hool, but I don't want the big one like a Van Hool and the ones Red Dot sells are fairly small it seems although I really have no idea how much A/C I really need, especially the driver with the large Dina windshields.
The nice thing about Red Dot is the many different configurations you can get. With the marginal cooling on most buses, I would highly recommend using a remote mounted condenser with a built in 12v fan. Personally I would think there would be enough unused space up front near or under the drivers seat that the condenser could be mounted there. Then all that would be added to the engine would be the belt driven compressor. Red Dot makes the A/C systems for Freightliner, Peterbilt, Kenworth and others-so they are both tested and reliable. Good Luck, TomC
I think air infiltration is the real FIRST ISSUE. Insulate all you want and get as big an air conditioner unit as you wish, but leave a window open and you are going to be at ambient. The frontal area of the bus has to be hermetically sealed and all the front has to be air tight cause that is a high pressure area and you let a really efficient flow of air into the bus with a comparitivly smallish hole up there.
Just sitting with the heat on I'll bet it is easy to keep toasty warm....even with holes in the front, so that isn't proof of good sealing.
Good hunting.
John
Fredward,
You have way to many air leaks causing huge heat gain while driving. Things like door seals, window seals, unplugged old ducts etc. I use a single 18,000 BTU/h ductless minisplit and can maintain 72 inside while driving 65mph on a sunny 95 degree day. On a similar day parked in the sun it was 70 in the bus.
Your results are about what I was getting with 2 'portable' heat pumps rated at 10, 000 BTU/h. The portables were simply fraudulently rated and really weren't delivering even 5,000 BTU/h .
Regards
Jerry 4107 1120
Jerry,
I think that is my problem. The RV windows are cheap and they rattle when I drive which means they must leak. I don't know that I have any major leaks in the front, but obviously there is a lot of hot air coming in somewhere. I've considered replacing the new windows with higher quality new windows. I still like the idea of putting a Red Dot or similar supplemental AC because then i wouldn't need to run the generator as much. We have a 2K inverter which will handle anything else necessary while driving down the road.
Fred
Fred- the power to run the A/C has to come from somewhere-whether it be running the generator, having a belt driven compressor on the engine, or extra drag on the engine alternator running the A/C through the inverter. Personally, just stay with the roof tops running the generator (it's what I have and like it) then you won't have the extra A/C system to contend with and the 35 ft of freon lines from the engine to the front of the bus.
Whether it be a 5hp draw on the big engine, 5hp draw to run two roof top airs, the amount of fuel burned is nearly the same to create the needed power for the air conditioning no matter what's powering it. Good Luck, TomC
So how much do these Red Dot units cost on average?
In my opinion, a separate engine driven bus A/C is the first class way to go. If I bought a coach that had it, I would attempt to keep it going. That is one reason I have considered a Wanderlodge in the past. That stated, since the coach I have does not have one, I would stick with the roof airs. For the front unit to really work for the driver, it would have to be as far forward as possible although I have seen a rooftop unit ducted to the front. I suppose this could even be a for-the-road-only removable duct or some sort of booster fan could be included to get the air where you need it. Our first regular motorhome had dash air but, since we lived in the desert, we found it best to curtain off the front of the cabin anyway. Unless one has unlimited resources, it's always a matter of prioritizing time and money. A new dash air system would not be at the top of my list.
If I were to buy another bus, I would give serious thought to keeping the over the road air and heat. That said, the system I have in my RTS is very comfortable. There are two Carrier 13,500 btu ducted roof airs with ceiling vents located where we need them. there are four vents up front that keep it cool. Last summer we drove for several hours with an oat of 98* with the sun comming in my side window, and it was still very comfy with the air on low speed.On High it freezes us out. Granted I have a lot less interior volume than a lot of you, but a properly designed roof air system will work fine, provided there is good insulation. Donn
Guys, if its so easy to cool these buses with 1 or 2 units why does it take 5 or 6 units with over the road air to keep the converted Prevosts cool that are foamed at the factory. just asking
Maybe size or glass area. I have 3 rooftop airs and I like to be cool. When my over the road air developed problems on a trip last year, the rooftops didn't come close to keeping me as cold as I like.
I also like to be cool ... some would call it cold... when I drive. The 76° mentioned in an earlier post, although at very extreme outside temps, wouldn't be cool enough for me. Our humidity sucks, too. I'd like it closer to 70°. The heat radiating off the windshield and driver's window is also pretty intense. I'm thinking that some of the factory 'conversions' have so many units (5) is because they're often painted black or some other dark color on the roof and that it takes 3 units to keep it cool throughout the bus normally, 4 to cool the back area, and the fifth one for when one's trying to cool the bus down initially or if one of the other units fails.
David
Last year I purchased a Red Dot system like Jim has with a remote mount condenser I haven't installed it yet because of all the work so I am thinking about selling it and going with the 110 unit from Proair or Dan Hard that way the inverter or generator ( if I need the crusie air to help) can supply the power on the road or I can use a power pole at RV camp ground.I know it won't have the BTU as the Red Dot but I won't have the 40 ft of hose and freon to worry about
Removing the o/t/r for space in this area, the bus was equiped with helper system in the back, this removed. I would like to use it up front.
Danny
What could one sell a complete working OTR air system for? (102a3) I think this would have alot to do with whether one would keep in it and deal with the extra maintnence or look elsewhere...
Many years ago, I sold a good compressor and condenser for $1000.00 and I don't expect their value has gone down. Those are the two components that get frequent replacement, while the rest of the components probably have not much resale value. Give them to the buyer of the compressor and condenser as a bonus if he gives you a good price.
Stan, did you sell those to me in Peterborough, back a number of years?
Big factory conversions have 5 roof airs, because at that price point, I'm not waiting for the coach to cool down if it has been parked in the sun. There is NO EXCUSE for the AC to ever not cool the coach in a noticeable way. No waiting. Excess capacity is part of the price of entry.
Bragging rights to make up for hidden inadequacies might play a part as well...
Riches have their rewards, and their expectations...
In commercial use, think band/entertainer/VIP bus, if there is a failure in a unit, there is redundancy and the coach can continue until it gets the time or to a location convenient for service (or is just left for the next user/owner by the less reputable leasers)
I was told, can't remember the source or the validity, that openings the equivalent of a 4 inch round hole would defeat our busnut efforts at AC, due to the air infiltration issue. Easily that kind of opportunity at the front of the coach, pedals through the floor, defroster, suction around the door is massive, through the electric panels beside the driver, the gap around the old door opening pushbutton on the front, the old air intakes on the sides, and out around every window seal, slider, crack and crevice.
Lots of places blow in by pressure, lots of places suck out by vacuum, due to the coach punching through the air.
Another reason the stock system was sized so large? infiltration, pull down and 39/41/43/47/55/56/57 people all living, breathing and sweating inside. Oh and the driver.... A busnut has only removed the large number of people, the rest of the loads remain.
happy coaching!
buswarrior
I have gotten Red Dot units out of a 15 year old school bus for free because those in Florida convert them into "goat" units for orange pickers. You could look up salvage yard for roll-over or badly front end damage or coach body already removed from chassis. It is a large unit that sets next to driver and another heater unit near above the rear dual wheel. School buses are very hard to cool & heat due to thin wall or no insulation and never ending infiltration....in other words their heating & cooling are bigger to accommodate the coach design.
I would be sure all leaks are stopped before changing to larger unit.
You can find leak the easy way by temporary attaching a discarded furnace blower on top of overhead vent or escape hole. Close all vents & heater air valves, then pail of warm water with ¼ cup of dish washing soap. Take a sponge mop with handle and apply the soapy water over joints (seal, metal, and fiberglass) and look for bubbles. You can use portable hand-pump pressure tank to wet-spray over what mop can't do. You will be surprised how many leaks you find.
FWIW
Sojourn for Christ, Jerry
I noticed in this posting that several have mentioned putting equipment in the spare tire compartment. Does that mean that you are running without spare tires? If so, what is the logic, and if not, where do you put the tires? Thanks
Lin,
There was a poll on spares; you can see the results and comments at
http://www.busconversions.com/bbs/index.php?topic=7148.0 (http://www.busconversions.com/bbs/index.php?topic=7148.0)
Bringing this topic back to life - would the consensus be that either using the coach AC or a Red Dot unit would be the way to go for over the road? After going through the maintenance manual I was enlightened to realize the factory coach AC was 90,000 BTU's :P
No wonder my puny 14,500 Furrion roof unit couldn't keep the front below 80 going down the road.
All it takes is money to make the coach HVAC work as intended.
And then more money...
That is why many busnuts remove the AC bits and design alternatives.
Happy coaching!
Buswarrior
Always a controversial subject. Here's my 2 cents worth...
If you have a OTR a/c system which is largely intact and which won't require too much effort and/or money to get and keep running, it can't be beat. Otherwise, unless you have an endless budget, look for other alternatives.
We were fortunate enough on both of our buses to have working OTR a/c systems. Our current bus was fully functional but for the compressor, and our compressor was not difficult or expensive to replace. The system was returned to fully functional (both heat and a/c) for about $3500, including a full recharge and a new compressor. Now it will turn the bus into a meat locker on a 90-degree plus day.
Were the system to ever take a deep dive, I'd be looking to other options. If you have a good working generator then your options are pretty wide open, including a pair of mini-split units or a pair of repurposed commercial refrigeration units like we have on our house systems. If you don't have an adequate generator, then the cost for one needs to be added to the mix.
Of course, there are options using inverters and a large battery capacity as well.
Consider the following fact - Restoring service on a typical roof air unit experiencing problems will be quicker and less expensive due to availability of parts and service than that for a 40 year old commercial passenger bus.
Unless you want another money hole, don't fool with it unless it is 1990 or newer. For what Richard has spent, for example, can buy 4 or 5 rooftop airs. Rarely do the majority of them require annual freon replacement or service. Add a bigger unit upfront and use the curtain idea to isolate the rear 3/4 or 1/2 of coach. Don't forget all the crud in the ductwork of the factory hvac system, which you'll never get completely clean. If you are starting a conversion, have the interior foamed before starting. That will reduce a lot of heat load. Probably a couple hundred dollars to service and add freon every year, and some freons are being phased out. You can run a generator going down the road for ac or use batteries and inverter, whichever you prefer. Also depends on how many miles you will be travelling every year in hot weather. Two or three hundred hours a year, then the factory system makes more sense. Driving into the sun is hot with a good hvac even in a car, due to radiant heat.
In a few months, we'll be talking about how to keep warm in the coach.lol🤔
I love all the speculation about OTR air by owners who don't have OTR, etc. Tends to be good entertainment. But I have a serious question about the compressor. What is the correct procedure to add crankcase oil? Is the crankcase pressurized?
I just added about 15lbs of r134 to my OTR and it was just barely enough to bring it up to the lower sight glass in the accumulator. Pressures were 50/225. Should it have a couple more lbs? If so what are the max pressures I should watch for?
A 30lb tank costs about $100, cheap for keeping the OTR air. I could handle that once a year.
Jim
Just be sure that your camping HVAC can pitch in to help, when there is a failure on the stock HVAC. It won't crap out at home in the driveway...
Empty system takes the whole bottle.
Compressor shaft seal, aged hoses, decayed o-rings, corroded condenser, half-assed repairs by previous owners, rubbed through metal piping from rubbing...
Once those are overcome, it's good until the usual busnut sitting around dries the seals and you start again.
Been there, done that, and will do it again.
Nothing performs like the stock HVAC.
Park in some wide open sunshine venue parking lot, closed up and heat soaked, the usual busnut solutions will take well into the night to cool the coach interior when you return after a day of recreation.
And the Admiral is not enjoying that...
happy coaching!
buswarrior
Ours took an entire bottle as well to bring it up from empty. Just shy of 30 lbs.
Quote from: DavidInWilmNC on February 02, 2008, 12:23:00 PM
... Another possibility would be a mini split, although not meant for vehicles, with the inside section mounted above the windshield or on the side right behind the driver. A 12,000 btu unit will run off 120 volts. If your generator is set up for 240 volts, you could use a 18,000 btu model. I suppose the easiest option, though, would be another roof unit (15,000 btu) mounted close to the front and ducted to right above the driver to cool the area heated by sun on the windshield. Good luck with it. Let us know what you decide to do. Being hot and driving for hours really sucks.
David
Hi, David. You're right about these possibilities, but I'm pretty sure that I remember Clifford ("Luvrbus") who writes on this forum has said that you need to have at least 48K Btu to keep the average bus cool going down the road. Of course, it the bus is unusually non-air tight and/or poorly insulated, you need to go up from there. That's why you see the "entertainer" coaches from Nashville with 5-6 12K Btu units on the roof.
Speculation??😚
Speculation??😚
Well, the DL has a 10 ton main evaporator, and 3ea 1-1/2 ton smaller evaporators, one behind the dash and two in the overhead bins. I'm not sure the system fully supports all of those since I seem to remember it being rated at 13 tons overall but they add up to 14-1/2 tons which is 174,000 btu. Even 13,000 tons is 156,000 btu. So somewhere between those two.
That's a lot of cooling. Even six roof units wouldn't really come close.
You can't get that from a shore-line. No how, no way. To get it from a genset would probably take a 40kw unit so that's not practical either. So the real question is, how much can you get?
New Homeowner's A/C units have been showing up with variable output compressors unless I'm mistaken. I do know efficiencies have risen to seer 22 or better, whereas the efficiency of the DL OTR might very well be under 12. So a modern compressor about half the size should give acceptable results.
How large of a compressor can you drive on a 50 amp shore line? Or a 30 amp line? That's the limiting factor.
Jim
Stock HVAC has a heavy fresh air component, and has to potentially cool 55 passengers.
Roof airs are closed loop, only wind driven air infiltration, and a handful of bodies.
Can't remember the BTU heating of each human body, it adds up...
Apples and Oranges, pick your fruit.
Happy coaching!
Buswarrior
Anyone want to hazard a guess as to what the pressures would be when you put enough r134 in the DL to fill the lower sight gage on the accumulator? I know on mine it would have to be over 50/225.
2nd question, is the compressor crankcase pressurized or not?
What is the correct procedure to add compressor oil?
What oil is specified?
Finally, has anyone had an issue with closing the condenser/door where it drags on the bottom and how did you fix it?
Jim
Condenser doors all drag, used to be a skid plate it rode on into place on some models. Nothing to fix. Lots of weight hanging there, don't be careless in leaving it hanging open except when directly working on it, you can see the mess a hinge or attachment failure will be to remediate...
Long ago, and I had knowledgeable help... we did the R12 to 134 swap, changed the oil from old kind to new compatible kind, it came in gallon cans, it drained and filled via plugs. There's a name for each of them, and they shouldn't be mixed up.
Yes, compressor is a sealed unit, that's why the shaft seal is a devil.
Gauges were the other guy's specialty, and he was more interested in the gauge readings than the sight glass.
Happy coaching!
Buswarrior
You boys Compressor look like this one?? Carrier O5G-Bus 41CFM
Nothing like a fresh compressor!
Happy coaching!
Buswarrior
That thing is huge compared to the little rotary compressor in my GM. Hard to believe that ours stays cool after seeing that monster.
Think it's a 6 cylinder monster. Bought this one from Carrier last fall and found out mine just needed a seal behind pulley. Now I have a 150 pound spare. Might have to bequeath it you somebody that needs a redo.
For comparison, here's the one on our GM 4108. It's not much different than what you'd find on a 60s or 70s Chevy or Olds.
Yeah, it's a beast.
So if the crankcase level is a bit low how do you add oil? (It just comes up to the bottom of the sight glass.)
I couldn't help noticing that there are valves on the lines so the pump can be isolated. So if you shut those off, open the crankcase and add oil, can you then evacuate the pump using the fill fittings on the compressor that you normally use to charge the system? It seems to me this would be the way but I thought I should ask.
As for the condenser door, it has sagged so badly that even with the skid plate it won't shut completely. In fact it hits the outside edge of that skid plate and stops. And if the fans are running when I try to close it it pushes the screen over into one of the fans. Not good. Not good at all.
Jim
Quote from: richard5933 on August 11, 2019, 07:55:05 AM
For comparison, here's the one on our GM 4108. It's not much different than what you'd find on a 60s or 70s Chevy or Olds.
Just curious, Does that ac/compressor set up keep your bus cool in extreme heat. Just got back from the Gulf Coast last week (Galveston) and in 103 degree heat, mine (Prevost stuff) would freeze you to death.
Quote from: muldoonman on August 11, 2019, 11:17:49 AM
Just curious, Does that ac/compressor set up keep your bus cool in extreme heat. Just got back from the Gulf Coast last week (Galveston) and in 103 degree heat, mine (Prevost stuff) would freeze you to death.
My bus was originally purchased for operation in NJ and surrounding states. I've used it in the summer between NJ and Gillette WY. So far we've driven in outside temps pushing the upper 90s, and the interior stays about 73 degrees. The driver's area is slightly warmer since it's in front of the air intake on the floor, but if the driver's fan is running it circulates the air and keeps things comfortable. With outside temps in the 80s the bus will be a meat locker if I want.
For operation in southern states and hotter climates, GMC offered an option to have two of the compressors mounted side-by-side to double the capacity of the system. The shared a common manifold on the rear so that they both tied into the refrigerant plumbing.
On the double-compressor setup I don't know if both were always running, but I suspect so. On mine the compressor can only be turned on with the oil pressure below a certain setpoint, and I would guess the same is true on the double setup.
I'm sure that if mine can keep things comfy in the 90s, the double compressor setup could easily cope with warmer temps.
Is this double compressor supposed to help me to know how to add oil somehow?
Jim
Quote from: Jim Blackwood on August 12, 2019, 12:38:34 PM
Is this double compressor supposed to help me to know how to add oil somehow?
Jim
Not really. I was just answering the question asked about it.
Doesn't the manual for the bus indicate how much oil is supposed to be in the compressor?
I would think his manuals, if he has them, would indicate this info.
I see, so basically there's one guy on here who might know and he ain't sayin'. S'OK, I can figure it out.
Jim
So, then you don't have any manuals? I can give you the info on the Trane 3 cylinder used on GMC's, but it may be too different from yours. BTW, they pump it in. A specific procedure.
I plan to buy the manuals on CD when I run down to Louisville to get a windshield but that will probably be sometime next summer. In the meantime I've got a not-very-good downloaded manual that doesn't match the bus and has missing parts and is on a computer I don't use very often to work from. I can look at it, it's in an out of the way place.
It's not the most urgent thing though, I'd rather get the condenser door fixed first. And somewhere along the line I need to get a tank I can evacuate the freon into. I have a refrigerator compressor pump that should be able to do that. Might be slow but I have time. For a tank I suppose I could use a 100lb propane tank that I have handy.
Sometime in the next couple years I plan to do some research and buy a couple of compressors to run off the shore line (may end up buying household condenser units depending on the price breaks and just remove the pumps) at which point I'll need to evacuate the system to work on the plumbing. Part of that plan includes solenoid valves to isolate the evaporators. In the end I expect to be able to run the three smaller evaporators (2 bin units and the dash air) off the new compressors, selecting the ones I want to run based on heat load and power available.
So, If I haven't added oil I can do it then. In the meantime I just want to keep the system operational and run it occasionally.
Jim
I looked up a few things.
System charge with r134 is 36lbs.
A full charge should show freon in the lower sight glass after running 30 minutes.
High pressure safety switch is 300psi.
Pump suction can be used to suck oil into the crankcase without purging any freon.
Oil should be checked after running for 30 minutes and with the engine off.
Level should be full at the engine side sight glass and empty at the curb side.
Do not overfill.
Jim
Excellent report!
Takes a lot of time to work on the coach AC
Definitely not yer car!
Happy coaching!
Buswarrior
I found that the condenser door can be muscled shut by lifting and shoving in stages, no doubt that is the accepted practice. Next time around I will look for some way to use a pry-bar on the bottom rear corner.
Some updated info.
Dash TXV is 1 ton, not 1-1/2 so total is 14 ton.
Evaporator motors are 2hp each (~65A) and appear to be set up to run in series or parallel. (for high and low speed)
Jim