[s-cars] a/c capacity...recharge
Jerry Scott
jerryscott at wispertel.net
Fri Aug 3 19:21:05 EDT 2007
Thanks Tom for the info.. I guess I just have to keep looking for an
adapter for the cowl port.
Jerry
Tom Green wrote:
> Jerry,
>
> No, this won't work. That port on the compressor is the suction or
> low pressure side and goes directly into the compressor. You have no
> means to vaporize
> the refrigerant that you add before it reaches the compressor pistons
> as a liquid and locks up the compressor destroying its value even as a
> core return. This
> valve has no use for the DIY person.
>
> The several posts recently on the subject of an adapter are for guys
> searching for an affordable adapter for that connection your guy used.
> It is under the
> low pressure switch near the evaporator. It has a schrader valve
> under the switch so you can remove it without losing refrigerant.
> However, the fitting is not
> the same as the compressor fitting, but a 10mm X 1.5 threaded fitting.
> The adapter will allow you to attach a standard gage set or the DIY
> can hose you have.
>
> You should still gage pressures, but at least, this will allow a DIY
> a/c tune up. The compressor needs to be running to add to the low
> pressure side. The low
> pressure side pressure drops when operating and allows you to use the
> small cans to replenish refrigerant--slowly. If you have gages on the
> system, you
> just watch the high side pressure to get it to the target pressure. I
> can only surmise that Audi left out a low pressure service port to
> eliminate the DIY mis-
> use. It is the most environmentally sound approach since it promotes
> capture and reuse of refrigerant for any a/c service. It's just not a
> very sound use of
> my dollar when I am not discharging any refrigerant.
>
> I had written an answer to your post to Jim Mairs to the effect I
> though it might be taken as advice to use the compressor port. But, I
> got a little too sarcastic and
> decided it would serve no useful purpose and dumped it rather than try
> to revise it. :-)
>
> Tom
>
>
>
>
> On Aug 2, 2007, at 9:15 PM, Jerry Scott wrote:
>
>> Tom
>>
>> So if one had the small cans to recharge the system, could it be
>> injected at the lower port on the compressor? The guy who did mine
>> with a large tank of R12 injected at the cowl port on the passenger
>> side, but I don't think that my can hose fitting will fit anything
>> but the compressor. He also had the a/c running while filling.
>> Should the system be running if filling at the compressor?
>> Jerry
>>
>> Tom Green wrote:
>>
>>>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
>>>>>
>>>>>
>>>_______________________________________________
>>>S-CAR-List mailing list
>>>S-CAR-List at audifans.com
>>>http://www.audifans.com/mailman/listinfo/s-car-list
>>>
>>>
>>>
>
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