Air Conditioning

[Don Bradner]

There've been a few A/C discussions in various threads recently - must be a
calendar thing. I thought I would add my own.

I've always been very impressed with how well the overhead chassis air cooled
driver and passenger in Blue Thunder. In previous SOBs on really hot days the
dash air was never enough - had to run the generator and a house A/C as well.
Blue Thunder is one of the 90s with the condenser back at the radiator rather
than on top of the front cap.

10 days or so ago there was a big heatwave on the west coast, and I turned on
the A/C for the first time in a couple of months - no cold at all, sigh. Ran the
generator as needed to keep things decent, and waited until we got home to check
things out.

On top of the hoses as they leave the compressor are R12-to-R134a elbow service
ports. Both were loose, and a small amount of pressure on the high-side fitting
caused it to separate. There was no gas escape, indicating that it was all
long-since leaked out.

I assume that I am the culprit on this. I had to drop the pump in order to
disconnect one of the gate valves when I was searching for my chassis heater
problems, and I'm guessing I hit the fittings at some point during the process.
They are rather exposed and easy to collide with.

A local outfit did the service, replacing both fittings and using 7-1/4 lbs of
R134a. An expensive lesson, for sure, over $600 bottom line.

The records from the coach's second owner shows a $700 bill in July of 2001 for
"A/C repair" so I'm guessing that may have been the original conversion.

I know there are a number of folks who have posted that their dash air does not
work, and they just use the generator/house air solution. We considered that,
but even with the high cost of repair the economics appear to be in favor of the
repair route. Our generator pulls about 1/2 gallon per hour when doing light
work like a single air conditioner. At $5 per gallon that would mean $600 would
run the A/C for 240 hours. At most that would be a couple of years for us, and
probably less. We will be traveling to the East Coast in August, and are likely
to be in hot weather until we leave Florida in November.

I'll be sorry if it turns out that I have a leak somewhere else, but I'm fairly
confident that I don't. The tech put plenty of fluorescent dye in with the
refrigerant, and nothing has shown up anywhere.


Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA