R134a Thread size?

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I want to recharge the refrigerant in my auto air conditioner. I've
assembled all the necessary tools except for one item. My vacuum pump
is outfitted with a 3/4" female NPT fitting and the discharge tube
from the gauge set is a R134a female fitting. I plan on machining an
adapter to get the 2 fittings connected to each other.

But I can't figure out what the thread size is on the R134a. Please
enlighten me!


Gary

Re: R134a Thread size?
gary wrote:
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1/2" Acme as I recall but I don't remember the pitch, sorry!

MikeB

Re: R134a Thread size?

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1/2" - 16 Acme according to this chart

http://www.epa.gov/ozone/snap/refrigerants/fittlist.html



Re: R134a Thread size?
wrote:

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  Don't reinvent the wheel by machining the fittings, it's silly to
waste $100 to $200 of your time on a $5 part - you only do that when
it's made out of pure Unobtanium...  Go to any refrigeration supply
house or search online.

  They have in-stock adapters to go from NPT pipe thread to 1/4" SAE
Flare (HVAC and Refrigeration charging hose fittings) 3/8" SAE Flare
(manifold to vacuum pump hose connection) and 1/2" Acme Flare (R-134a
Automotive Manifold hose fittings)

Your vacuum pump should have 1/4" SAE Flare and 3/8" SAE Flare
fittings if it was made for refrigeration work - you connect the
manifold hose with the 3/8 fitting, and can attach the micron vacuum
gauge to the 1/4" to monitor your progress.

  (If the system under vacuum has an extra service port, connect the
vacuum gauge sensor directly to it.  That way you can isolate the
system with a ball valve and shut off the vacuum pump, and monitor the
vacuum levels for leaks and/or trapped moisture still evaporating from
the refrigeration oil.

  If you are adapting an industrial vacuum pump, you'll have to
bushing down from 3/4" NPT down to the threads needed for the adapter.

--<< Bruce >>--

Re: R134a Thread size?
gary writes:

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Beware you don't commit an EPA felony.  Such adapters are not government
approved.

Re: R134a Thread size?
On Sun, 14 Jun 2009 23:59:03 -0500, Richard J Kinch

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  What the (heck) are you talking about?  They don't have to be
"government approved".

  Unless they've made some serious changes since I took and passed the
test, there are no approvals processes or "lists of approved
machinery..."  You just have to use procedures to reduce accidental or
incidental release of CFC's and HCFC's as much as possible.  And
deliberate release is instant trouble.

A car using R-134a is running an HFC.  No chlorine.

--<< Bruce >>--

Re: R134a Thread size?
Bruce L. Bergman writes:

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The EPA via the Clean Air Act regulates what fittings can be used with what
refrigerants.  Not the marketplace, not engineering standards, not the
convenience or expedience of you or me or the OP.  I don't agree with the
despotism of the government, I'm just warning you.  The law makes us all
criminals, even for things like cutting metal. The tender mercies of the
bureaucrats decide who is punished and who is given lenience.

Re: R134a Thread size?
On Tue, 16 Jun 2009 02:40:58 -0500, Richard J Kinch

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  The service fittings permanently installed on the vehicle or
stationary system, yes.  If you do a conversion from R12 to R134a or
another refrigerant you have to change the fittings to the proper
style to avoid accidentally mixing refrigerants.

  But not an adapter made so you can hook up your service manifold
hoses to the car or refrigerator being serviced, or hook up the hose
from your vacuum pump to your service manifold.  They may be stupid
MF's working for the government, but they ain't THAT stupid.

  It's the mouth breathing politicians who wrote the impossible to
follow laws the bureaucrats are trying to (selectively) enforce who
*are* that stupid.  Which is why politicians are like diapers - they
need to be changed often, and for the same reasons.

--<< Bruce >>--

Re: R134a Thread size?
Bruce L. Bergman writes:

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The EPA holds that if certain fittings are required, then adapters to
circumvent them are not permitted, since that defeats the very purpose of
the fittings, namely to make impossible the mixing or confusing of
refrigerants.  While the utility of adapters is obvious, you're supposed to
have a separate set of gages and hoses for each refrigerant.  That's the
governmental logic: intelligent economizing must give way to backstopping
presumed stupidity.

As Uncle Al sez, environmentalism is expensive, shoddy, and deadly.

Re: R134a Thread size?
Bruce L. Bergman wrote:
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Want to bet!

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True, It is a shame that the Constitution was written by folks who felt
that serving in government was such a PIA that nobody would WANT to do
it. Term limits were not considered because of that.

I'd like to see term limits for ALL elected offices. Never going to
happen though.



--
Steve W.

Re: R134a Thread size?
Steve W. wrote:
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The founders all had things to do, like managing a business.
Government duties detracted from that.

I sure wish the people in Washington DC had other things to do.
Idle hands truly are the devils workshop

Re: R134a Thread size?

RB wrote:
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   Even the Devil has standards.


--
You can't have a sense of humor, if you have no sense!

Re: R134a Thread size?
Michael A. Terrell wrote:
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Like the old joke about the testing lab that is switching from rats to
lawyers:

1 - Lawyers are more numerous
2 - Nobody cares what you do to a lawyer
3 - There are some things even a rat won't do

Re: R134a Thread size?

RB wrote:
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   They multiply exponentially.

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   Except another lawyer, but they don't matter.

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   Not when there are so many out of work law students who weren't smart
enough to bribe their way past the bar.



--
You can't have a sense of humor, if you have no sense!

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