Date: Thu, 7 Sep 2000 12:28:14 +1100
Reply-To: David Del Ben <ddelben@AIRINTER.COM.AU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Del Ben <ddelben@AIRINTER.COM.AU>
Organization: Air International Transit
Subject: Vanagon Air Conditioning
Content-Type: text/plain; charset="us-ascii"
I'll aswer your question in a number of parts;
1. What I did to my existing A/C
I bought my Vanagon just over a year ago now - and it had exactly th same
set-up you described - down to the 2-piece condensers located in front of
the radiator. It was an R12 system, and it wasn't working.
I looked at it and said Yuk, Yuk, Yuk - ripped it all out and threw it
away.
What I 'intend' to replace it with is:
Hi-Tech Parallel Flow Condenser
Plate and Fin Evaporator Blower unit located under the rear seat
Electronicly speed controlled High pressure blower that will blow the socks
of you in terms of airflow
More modern Sanden SD7H14 Compressor
Electronic Climate control
I've got all the bits and pieces [from when I worked in our automaotive A/C
division - samples, prototypes, etc - he he) - I just need to find time to
do all the design of the Blower unit, mount the condwnser , etc and get
someone to pipe it up. Thought I would have it in by last
Summer............still not there.
2. Why I took the old system out
A number of reasons:
a) There are so many hoses, connections, etc that there WILL be gas leaks.
All automotive A/C systems leak gas - through the crimp connections on the
hoses, through the pipe to pipe flare fittings, throughthe rubber hoses.
They all leak, and they have 'permissable' leak rates in grams/year. The
hose & conection nightmare on the system I (and you) had promotes leakage.
b) I am fully confident that my (and your) system was installed by - maybe
not backyard mechanics - but not experst either. It is bloody hard to
design and balance a system like that - 1 Condenser/2 Evaporators. What
happens if you turn 1 coil off - what happens to the other system? What
about oil return back to the compressor? I've never designed/balanced a
system like that before - and I don't really trust anyone else doing it
unless I'm sure they were competent. I'm sure that you'll get cold air out
'most of the time'. But - how cold? And what about those high condenseing
temps/pressdures you're describing. And what about the compressor cutting
out on HP/engine overheating?
Not a very well designed system!!!!!!
3. My advice to you
I agree the cold air out the vents at the front is desireable. (I intend to
convey the cold air from under the seats to the inlet of the A/C box under
the dash. Apparently there is an opening there for the Booster Heater unit
if supplied but plugged up otherwise. I intend to convey cold air through
it instead of hot air. My High static blower should push the air more
substantially through the front vents, and also through the front doors, to
the rear overhead vents. That way - I'll use the excellent vanagon
distribution box - that's the theory anyway - I guess there will be a bit
of mods here and there to make it work!!
a) I don't advise you doing what I did - not patronising here - but you
don't have the expertise or access to the bag of goodies I have.
b) As far as the condenser goes - I've got the same problem. I don't have a
genuine VW Condenser - but it's a good one. Don't know how or where to make
it fit at the front - and I've crawled all over my car to look for an
alternative spot. I've also got a high capacity slim-line condenser fan to
boot. So.....can't offer anything there. I thought of doing what you
suggsted - it may work - but going from my experience 'it's not a good
idea' - not very robust. The best I've come up with is to mount the
condenser to my Bull Bar at the front, and protect it accordingly. I
actually saw a Type II air-cooled bus a few months ago that had exactly
this.
Again - I don't think it's a good idea - not very robust. So, the jury is
still out on this issue.
c) Your Overheating problem
hhhhmmmmm. I would probably recommend against the additional condenser and
fan - simply because of the mounting, additional pipes/connections (read
leakage points) etc. Also not too sure if the condensers in series will
reduce your head pressures that much. [One of our bus A/C's had the
condensers in series a while back & testing showed that it didn't make that
much difference to the pressures - I still don't think it's a good idea -
that's personal with no evidence to back up].
I would recommend 2 options:
Wire the radiator fan to run on high speed when the A/C is engaged. From
what your telling me - this was not done. The engine thermostat should
temper the coolant flow to maintain the correct engine temperature.
If that doesn't work for whatever reason - you need more condensing - .
your system's sounds hopelessly inadequate. Maybe take it somewhere and ask
about the possibility of installing a bigger condenser/bigger fan - or else
do it yourself if you are that way inclined. Those fans on the WBX's (I've
seen mine) are pretty old. They have more modern slimline versions that
push more air.
4. Moral of the Story
You've probably gathered that I am a bit fussy.
I go by the principle that if you do something - put a bit of
thought/engineering behind it so it will work 100% of the time - not 90% of
the time like the system you have. Then you wouldn't have your car
overheating, you wouldn't have the compressor cutting out on High Pressure.
Ca you imagine the uproar if VW or GM or Ford put out a car that worked
great - for 90% of the time - but if you happened to turn the steering
wheel left with your foot on the gas pedal at 20% - the engine would cut
out????
That's the difference between OEM & (shonky) aftermarket.
David Del Ben
85 1.9 - Vanagon
-----Original Message-----
From: edmclean@bellsouth.net [SMTP:edmclean@bellsouth.net]
Sent: Wednesday, September 06, 2000 3:23 PM
To: ddelben@airinter.com.au
Subject: Vanagon Air Conditioning question
Hi David,
I have read your recent posts to the Vanagon mail list and I was very
interested that you said you design bus air conditioners for a living.
I have a 1986 Vanagon with a somewhat unusual problem and I was hoping
you would help me by offering some advice. My description below is
quite long but I don't think
I have a '86 Westfalia that has modified air conditioning system. The
original rear evaporator unit is supplemented by an in-dash front
evaporator unit (sold by Cooler-Air but similar to the Behr units
installed in the early '80s in the US). The compressor is a Sanden 709
unit, the refrigerant is R134a, and the condenser is the original VW
part that has two sections of coils mounted in the standard location in
front of the radiator. The thermostat for the front evaporator controls
the compressor clutch and the thermostat for the rear evaporator
controls a solenoid valve in the refrigerant line to the rear
evaporator. The system works very well when the bus is moving but is
less effective when standing still (as expected). Having a source of
cool air in the front of the bus really makes it a joy when driving in
100+ deg F weather. The only problem is the system pumps out so much
heat in front of the radiator that the engine temperature rises somewhat
when climbing up mountains at high altitudes. If I turn off the
compressor the engine temperature is very well controlled. The radiator
is in good condition (3 years old) and the radiator fan is working
correctly with the most recent version of the two speed temperature
switch. Occasionally the high speed fan comes on and the engine
temperature rapidly falls until the fan cycles off. Sometimes when I am
driving slowly or in town in hot weather the high pressure safety switch
cycles off the compressor until I increase my speed and more cooling air
is available to the condenser.
To summarize, the air conditioning system is working very well and quite
normally but I just don't have enough condenser capacity. If the
condensor capacity was greater I would be able to remain cool in
traffic. In order to increase my condenser capacity and also to move
some of the heat from in front of the radiator I would like to install a
secondary, fan cooled, condenser between the compressor and the current
condenser. There is probably enough room under the center of the bus
between the frame rails but I would need to have a very thin fan above
the condenser and I would need to protect the entire addition from road
hazards, probably with expanded metal grid and heavy screen wire. I
know this is not the optimum location because of the high temperature
close to the road with the hot air coming off of the radiator but I
think this would work. I would like to ask if you have any experience
with Vanagon air conditioner condensers not mounted in the traditional
location? Do you have any suggestions? Do you sell or know of a source
for an auxiliary condenser that could be mounted under the bus or
somewhere else? Do you have anything else to add?
Thanks for your help. If you don't wish to answer these questions,
please just reply and let me know.
Thanks for your help.
Ed McLean
North Carolina, USA
email99@bellsouth.net
