Putting freon in the road air system

[Dietrichfarms]

my 78 MCI still has all the road AC system in place.  PO told me when I purchased it that the system was low and he didn't ever run it. I have 2, 30lb bottles of freon 12 to charge it with but can't find any pressures in the manual. Do I go solely on level in sight glass up at condenser ?

[chessie4905]

   Is it "low" or empty? If empty, you need to pressure check it before wasting the R12. Rarely is it practical to try to maintain coach AC unless it is only a couple of years old $$$$$. I won't even go into proper training and certification to handle refrigerant/ AC systems.

[Dietrichfarms]

I believe it's low, I haven't turned it on yet. PO had run it and it wasn't getting very cool, bus came from northern Ca so he didn't need it he said. I'm in texas so different story.

[luvrbus]

1/2 of the glass on the lower glass at the receiver is normal you may need to adjust  

[eagle19952]

It went somewhere...

Why wouldn't you suck it down and pressure test it...??

[krcevs]

Are you sure the road air uses R12 and not R22?
What kind of system? Is it a sanyo automotive type compressor that you could find in a car, or maybe a trane  multi piston type of compressor that you find in a coach?

Ken

[luvrbus]

If his 8 hasn't been changed over to R134 A they did use R12 or R500 mine did before I changed to 134

[moosemanusa]

Conversions to 134a usually have lots and lots of stickers everywhere showing that fact..

Would have to check the whole R12 / R22 question with the make and model of the unit, all the buses i work on are typically R22.

As stated already regarding the sight glass, if nothings visible, vacuum it down to see if it holds pressure.

[Jim Eh.]

Does the A/C clutch "engage"?

[luvrbus]

If his is original he does have a 3 cylinder compressor and it does takes R 12 or 500 no R22 it is a 7 ton unit and when working you can hang meat in a MCI 8.It was disappointing to me when I changed over to 134 all the money spent and less cooling lol the stickers where made by a Mark A Lot felt pen 

[Hi yo silver]

The previous owner of the MC9 I owned had put R-414 in the OTR system. Shortly after I bought it I took it to the folks at Thermo King. They advised the 414 was intended for stationary systems. They pulled a vacuum on it, replaced a faulty valve with one I ordered through Southern Refrigeration, and refilled the system with Freeze 12. It was still cooling well when I sold the bus a few years later. That said, the bus, having been converted new by Custom Coach, didn't have a million miles on it. If I was looking at a system with many more miles/hours on it, my decision to put $$ into it might have been different. Just my experience.

[muldoonman]

Put the gauges on it. If it's got ANY pressure on it, just freon it up. If all gone , I would look for a leak or leaks.  On the quote "Rarely is it practical to try to maintain coach AC unless it is only a couple of years old $$$$$." That's nuts. Mine is 24 years old and after changing the rotten hoses after I bought my coach 4 or 5 years ago, still a cooling. If you get it working, nothing better than freezing folks out in 100 degree weather riding down the road.

[moosemanusa]

I've found that the AC industry will do its most to scare people away from doing their own maintenance.. Go read the forums on HVAC, its comical!

The AC automotive certification is an open test book online!

You'd think these "pro's" were defusing IED's the way they speak (on HVAC forums)

[luvrbus]

I am curious where he found 60lbs of R12 at a price you can afford I sure hope he didn't get taken like me and paid for propane

[moosemanusa]

Lots of those..

A few years back we were sold some R22A HC (Super Freeze).. was just propane..

Didn't work one bit! had to vacuum out the system and charge with the real stuff!

I heard the FBI calls customers (internet rumors) to obtain order information.. just search R22a and you're see the posts..

Now if we get sciencey, propane will work to a certain point but thats too boring to go into!