[s-cars] AC low side recharge adapter

[Young, Steve]

Just be careful with jumping out safety switches.  If your system is so
low on charge that it is being held off by the low pressure switch,
jumping it out and running the compressor can cause damage and toast the
compressor.  In most A/C systems, the refrigerant carries a portion of
the oil throughout the system.  With no refrigerant, there may not be
enough oil at the compressor for proper lubrication = toast.  Jumping
out the low pressure switch is fine if you are just topping off the
charge.  If the system is empty, not the best idea, especially if you
are a DIY'er.  If you are an A/C tech, you can probably meter in the
charge fast enough to keep the compressor from lunching.  The tendency
as a DIY'er is to DUMP in the charge fast.  This puts liquid refrigerant
at the compressor valves = toast.

When I get to servicing mine, I'll post if I have any luck with a
permanent adapter fitting.


Regards,

				TRANE
Steven Young
Local Operations Manager
Albany Office




-----Original Message-----
From: Tom Green [mailto:trgreen at comcast.net] 
Sent: Tuesday, July 03, 2007 1:00 PM
To: chris chambers
Cc: Young, Steve; s-car-list at audifans.com; kentmclean at comcast.net; Aaron
Ryba
Subject: Re: [s-cars] AC low side recharge adapter

That "adapter", perhaps in group buy quantity, is what this list
desires.
Your help in finding the what and where to source this part  would be
appreciated, Chris.

I didn't elaborate before, but it is below the low pressure switch, and
you can just leave the switch disconnected and short across the
electrical contacts so the compressor will run while using the port.

Tom

On Jul 3, 2007, at 12:37 PM, chris chambers wrote:

> Gentz,
>
> There is a switch on the passenger's side up near the windshield, a 
> local tech uses an "adapter" where he threads out the switch and puts 
> in the adapter and fill/reads gas there.
>
> I'll ask him for more specifics next time I'm down there.
>
> Chris
>
>
> --- "Young, Steve" <sryoung at trane.com> wrote:
>
>>
>> Having read these A/C posts with interest, I'll add my $0.02.  I will

>> be looking into my A/C system soon, as it provides no cooling.  So 
>> bear with me as I have done no investigation to date.  If the low 
>> pressure cutout switch is the type that screws onto a threaded 
>> schrader valve port, any refrigeration supply house should have a tee

>> fitting that could be installed between the A/C line port and the 
>> cutout switch leaving an additional port for gauge hookup.  This 
>> assumes that there is physically enough room to add the tee, and then

>> orient it so that a gauge hose can be attached.  It also assumes that

>> Audi did not use a fitting with a non-standard thread.
>>
>> http://www.grainger.com/Grainger/items/3GD02
>>
>> An alternative would be the pick up a braise in port fitting and 
>> install it in a manageable place on the low side of the system.  If 
>> you system is already empty, this option will take about 30 minutes 
>> to install by drilling the proper hole in the low side line, and 
>> braise in the fitting.
>>
>> http://www.grainger.com/Grainger/items/3X729
>>
>> Or use something like this.
>>
>> http://www.grainger.com/Grainger/items/3WU91
>>
>> YMMV, and please verify the line size before purchasing.
>>
>> Regards,
>>
>> 				TRANE
>> Steven Young
>> Local Operations Manager
>> Albany Office
>>
>>
>>
>>
>> -----Original Message-----
>> From: s-car-list-bounces at audifans.com 
>> [mailto:s-car-list-bounces at audifans.com] On Behalf Of Tom Green
>> Sent: Tuesday, July 03, 2007 10:31 AM
>> To: s-car-list at audifans.com
>> Cc: calvin at earthlink.net
>> Subject: Re: [s-cars] AC low side recharge adapter
>>
>> This issue has been revisited many times without any definitive 
>> answers given to the list.  The most often asked is about adapting a 
>> gage set to the low pressure port for a DIY recharge.  But no one has

>> offered any specific details for this even if they said " I did this 
>> myself".
>> Even
>> the local dealer service manager claims they never use the low 
>> pressure port, only connect to the high pressure port at the 
>> condenser, evacuate and refill a measured charge with the engine off,

>> and measure the high side pressure and interior duct temperature for 
>> any fine tuning of the charge with the engine running at 2K rpm.  
>> There is some risk of introducing liquid refrigerant into the 
>> compressor by using the low side port if you are not careful or 
>> overcharge the system even though shops use this system on most 
>> vehicles, and of course, the high side pressure will burst a DIY can 
>> and will only allow a recharge with the compressor off.
>>
>> My high side valve is on the front right side of the condenser and 
>> easily accessible on the S6.  I don't know about the R12 systems on 
>> the S4.
>>
>> Is there someone on this list who can put these issues to rest?
>> That is, can someone provide a source for a low side adapter?  Does 
>> anyone have specific details of the differences in the URS4 systems 
>> using
>> R12 and the URS4/6 systems using R134a?
>>
>> Tom
>>
>>
>>> Date: Mon, 02 Jul 2007 21:24:49 -0400
>>> From: Kent McLean <kentmclean at comcast.net>
>>> Subject: Re: [s-cars] AC low side recharge adapter
>>> To: s-car-list <s-car-list at audifans.com>
>>> Message-ID: <4689A561.5060607 at comcast.net>
>>> Content-Type: text/plain; charset=ISO-8859-1
>>>
>>> Aaron Ryba wrote:
>>>> Like others have mentioned I took off the low pressure switch (F
>>>> 73) located in
>>> the right
>>>> plenum and planned on filling her up there however it seems like
>> the
>>>> threaded male connection with the schrader valve there is a metric
>> 10
>>
>>>> mm thread size which won't work with anything I can get at
>> Autozone
>>>> or Advance Auto parts. I am trying to avoid spending $100 bucks on
>>
>>>> the high end manifold gage set or paying a shop $120 to fix it for
>>
>>>> me.
>>>
>>> I'm almost in the same boat.  With 3 Audis with weak or no AC, I 
>>> thought I'd be better off investing in the equipment and doing it 
>>> myself. I bought the not-quite high-end manifold gage set ($60 at 
>>> Robbins, a supplier to mechanics in S. NH, not the $39 set at the 
>>> local national consumer chain.
>>> Plus another $30 in the R134a-specific hoses.). I bought the R134a 
>>> adapters.
>>> I haven't gotten around to actually doing the conversion(s) yet.
>>> But my
>>> understanding so far is that the gage sets needs to tap into both
>> the
>>> high- and low-pressure sides of the system, so you still need to
>> have
>>> access to a low-pressure side valve.
>>>
>>> My am also under the impression is that the valve on the compressor
>> is
>>
>>> meant to drain the oil from the compressor, but as it is on the
>> low-
>>> pressure side,
>>> -- and here I'm not 100% sure/convinced -- it can be used to
>> recharge
>>> the system. I'll leave it to someone with more experience to
>> confirm
>>> or reject that idea.

>>>