[s-cars] a/c capacity...recharge

[Tom Green]

There are no VAG specific tools used to evacuate and charge the
system Jim, even at the dealer.  The high pressure port fitting fits  
on a standard
automotive a/c gage set, Kent-Moore or similar, or the newer recovery  
units with
integral gage set.  Your HVAC friend should have no trouble  
evacuating and
charging the system using the standard high pressure port.  There may  
be some
question of how much oil to add back to the system.  With your system  
already
back together you won't be able to drain the compressor to change the  
oil and
check quantity.  If you didn't drain or blow any oil from the  
compressor, I would
assume it is still full and only add the make-up for the accumulator,  
evaporator
and condenser, or 2 oz according to Bentley.  If it was drained, add  
2.7 oz in the
compressor through the drain plug and the rest through the gage set when
recharging to make up the 8.5 oz total.  There are some universal  
oils out there,
my compressor has pag 100 in it.   Oh, the drain is on top of the  
compressor, so
you can't drain it if it is bolted to the engine.

An accurate scale to measure the amount of refrigerant removed from  
the tank
should result in around 100 psi on the gage, and 290 psi operating  
(close tank
valve first).  The electric fan should operate and the engine fan  
clutch locks up
when the engine gets to operating temperature.  Turn the a/c to low  
and recirc
and you should have cold air at about 40 F.

What your a/c friend may not like is there is no service port to  
check the system
balance and and fill and fine tune the system while operating, so you  
have to
shut down, cool off the system after you've got it really hot  
checking it out, just
to add another 1/2 oz or so to fine tune the operating pressure and  
duct temp
for optimum performance.  I guess you could put the gage low pressure  
hose
connection on the compressor fitting for a reading, but the one you  
want is at
the orifice, and don't even think about adding liquid refrigerant  
there.  You need
to know what you are doing to add it at the orifice so no liquid  
reaches the
compressor.

The threads you have been following and a friend with HVAC tools should
make this a no-sweat (pun intended) operation.  The extensive threads  
are
just guys wanting an easier way because they don't have a HVAC  
friend, and
just need a little make-up after 10 years operation.  Bentley has  
extensive
coverage for a/c diagnosis and repair.

Check the links I just gave to Floyd on his oil pressure and other  
questions.
The corporate history of several years of s-car ownership and repair  
are on
those sites and a few others.

Tom

> Date: Thu, 2 Aug 2007 14:55:21 -0400
> From: "James C. Mairs" <jmairs at cetaq-americas.com>
> Subject: Re: [s-cars] a/c capacity...recharge
> To: "'s-car-list'" <s-car-list at audifans.com>
> Message-ID: <01c601c7d536$ada4d6c0$0b03a8c0 at CeTaQJCM>
> Content-Type: text/plain;	charset="us-ascii"
>
> Greetings Tom,
>
> Excellent information, I have been following the AC threads for  
> some time
> now, trying to determine if anyone actually has followed through  
> with a
> recharge without going to the dealer.  Lots of information but not  
> a lot of
> BTDT with answers...
>
> Appreciate the info, side note the charge in the system was working  
> fine
> before I tore the entire front end out and apart for a head  
> rebuild, coupled
> with a lot of while I am in there fixes and replacements.
>
> AC in the car was working before breaking open the system, however  
> I wish I
> had gone through the diagnostics to see how well it was working  
> (HVAC codes
> and such) before taking it apart.  Alas a compromised head was  
> leading me to
> not wanting to run the car for long periods of time.
>
> AC system was sealed back up after replacement of the dryer and new  
> Variable
> Orifice Valve.  All lines separated were put back with new seals,  
> and of all
> the lines only 1 was I able to flush completely before reassembly,  
> mostly
> due to being to far into the project to want to spend more time and  
> money.
> The others were just disconnected and compressed air to blow out  
> whatever
> black sludge wanted to go flying out from whatever end wasn't pointed
> downward.
>
> Hope some other folks post up information if they have completed  
> this as a
> DIY job.  Especially the fittings and procedure when not having the  
> correct
> VAG tools...
>
> Thanks again Tom, if anyone else has any links or key words of  
> wisdom to
> offer I am more than all ears.  Or if you happen to have any good  
> archive
> thread searches I can use, mostly looking for BTDT's or things to  
> watch out
> for, it would be appreciated.
>
> Thanks,
>
>
> -Jim
>
>
> -----Original Message-----
> From: Tom Green [mailto:trgreen at comcast.net]
> Sent: Thursday, August 02, 2007 11:14 AM
> To: s-car-list; jmairs at cetaq-americas.com
> Subject: Re:[s-cars] a/c capacity...recharge
>
> Jim,
>
> Capacity is 21.2 to 23 oz refrigerant and 8.5 oz of Pag oil.  The
> high presssure port on the passenger side of the condenser is the only
> port used and evacuated and charged with engine off.  You can only
> measure the oil charge if you drain the oil (at the condenser) and
> change the accumulator since an unknown amount collects there.  The
> real trick is accurately measuring the refrigerant charge.
>
> If the system is in good condition with all fans and flaps working
> correctly in
> recirculate mode, the result should be about 40 F duct temperature at
> 95 F ambient.
>
> The system base pressure is 113.1 psi at 95 F (engine off) and 290 psi
> operating pressure with a full charge.
>
> Tom
>
> -----Original Message-----
>> Date: Wed, 1 Aug 2007 18:24:47 -0400
>> From: "James C. Mairs" <jmairs at cetaq-americas.com>
>> Subject: [s-cars] AC Capacity...Re-Charge
>> To: "'s-car-list'" <s-car-list at audifans.com>
>> Message-ID: <015801c7d48a$c4c727b0$0b03a8c0 at CeTaQJCM>
>> Content-Type: text/plain;	charset="us-ascii"
>>
>> Greetings all,
>>
>> Bentley Manuals are in route via shipping, so I can not confirm the
>> following, or even if its listed.
>>
>> Does anyone know the capacity/recharge pressure amount for a 93 //S4?
>>
>> I have been following the threads here as much as possible on the
>> whole AC
>> snow flake conversation, as well as a quick search in the archives.
>>
>> I have a HVAC friend who is willing to run a vacuum test on my
>> system before
>> recharging it.  He doesn't seem to think it will be an issue, but
>> informed
>> me I should confirm what amount of R134 should be in the system.
>>
>> He has a large amount of fittings/adapters and such, its possible
>> we may
>> even just plumb in a connector with a generic fitting to make this
>> easier in
>> the future.  If/when I come up with a solution I will be sure to
>> post up my
>> findings... However in the mean time sitting in 93 degree heat in a
>> black on
>> black S4... I have to ask...
>>
>>
>> Anyone care to toss out a number?
>>
>>
>>
>> -Jim