What are normal R134 pressures?

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Old 31 Aug 2006, 10:07 am   #1 (permalink)
geronimo
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Default What are normal R134 pressures?

I am going to try a 134a retrofit, what should normal hi/low system
pressures be when operating?
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Old 31 Aug 2006, 10:38 am   #2 (permalink)
geronimo
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Default Re: What are normal R134 pressures?




Should have mentioned that it is an 1988 Camry wagon. COuld not find
any R12 refrigerant charge/capacity sticker on it. The retro fit kit
comes with two 4 oz cans of oil. It says to use both...but do I really
need 8 oz of oil on this little car?
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Old 01 Sep 2006, 10:10 am   #3 (permalink)
johngdole@hotmail.com
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Default Re: What are normal R134 pressures?

Low about 20-35; Hi about 200-230. Towards the higher end with higher
ambient temperatures. I don't know why any company spec out 25, because
the pressure switch typically shuts off at 25-28psi. Check
http://www.id-usa.com/how_to.asp

Interdynamics has how-to videos and other FAQs on their web site.
Excellent reading/viewing.

geronimo wrote:
> I am going to try a 134a retrofit, what should normal hi/low system
> pressures be when operating?


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Old 01 Sep 2006, 11:00 am   #4 (permalink)
geronimo
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Default Re: What are normal R134 pressures?

Before I do it, I am thinking it would be good to drain out at least
some of the old mineral lubricant. What are the low points where there
are fittings I can take apart to drain? bottom fitting on condenser?
receiver/dryer? I figure whatever is the low point should be where
most of the oil has collected. Don't know how to get to fittings on
the evaporator....would oil drain out from there?


On 1 Sep 2006 08:10:45 -0700, johngdole@hotmail.com wrote:

>Low about 20-35; Hi about 200-230. Towards the higher end with higher
>ambient temperatures. I don't know why any company spec out 25, because
>the pressure switch typically shuts off at 25-28psi. Check
>http://www.id-usa.com/how_to.asp
>
>Interdynamics has how-to videos and other FAQs on their web site.
>Excellent reading/viewing.
>
>geronimo wrote:
>> I am going to try a 134a retrofit, what should normal hi/low system
>> pressures be when operating?


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Old 01 Sep 2006, 11:51 am   #5 (permalink)
johngdole@hotmail.com
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Default Re: What are normal R134 pressures?

The oil will be distributed in the pipes, evaporator, condenser, and
compressor, mostly in the compressor and then in the evaporator and
condenser. If you drain only the compressor there will still be about
40% left in the system. There are no "drain plugs" on evaporators or
condensers.

There are AC cleaners used by the shops to flush out the system, and
Interdynamics sells the following:
http://www.id-usa.com/catalog.asp?CID=12

A typical r12 --> r134a conversion does not require you to drain the
oil -- that's what the Interdynamics video on the conversion says.
Doing so takes extra time and may introduce dirt and moisture into the
system. You may want to consider draining/flushing when you need to
open up the system for other work like replacing the compressor if
ever.

Actually, you can contact Interdynamics about these questions. But
check their FAQ and how-to videos first. Let us know if you do.

Consumer Assistance:
Have you tried our Frequently Asked Questions (FAQ) section?
CONSUMER@ID-USA.COM
888-318-5454




geronimo wrote:
> Before I do it, I am thinking it would be good to drain out at least
> some of the old mineral lubricant. What are the low points where there
> are fittings I can take apart to drain? bottom fitting on condenser?
> receiver/dryer? I figure whatever is the low point should be where
> most of the oil has collected. Don't know how to get to fittings on
> the evaporator....would oil drain out from there?
>


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Old 01 Sep 2006, 01:24 pm   #6 (permalink)
geronimo
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Default Re: What are normal R134 pressures?


OK, the website answers the questions not specific to a particular
car. Mines' a 1988 Camry 3SFE, 4-cyl. I would like to have an idea
how many ounces of R134a and how many oz of ester oil I will need to
put in. I think this varies from car to car? I will be starting with
an evacuated system but with mineral oil still in. Seems like mineral
oil left in would take up space in the system, allowing less R134a and
oil for the recharge....but it doesn't significantly reduce the
recharge volume if a lot or all of the old oil is left in? I looked
all over for a sticker stating the original R12 refrigerant charge,
but could not find any, so I don't know what to expect should go in if
all is going right. The Haynes manual doesn't say much at all on the
AC!

Thanks, Geronimo


On 1 Sep 2006 09:51:15 -0700, johngdole@hotmail.com wrote:

>The oil will be distributed in the pipes, evaporator, condenser, and
>compressor, mostly in the compressor and then in the evaporator and
>condenser. If you drain only the compressor there will still be about
>40% left in the system. There are no "drain plugs" on evaporators or
>condensers.
>
>There are AC cleaners used by the shops to flush out the system, and
>Interdynamics sells the following:
>http://www.id-usa.com/catalog.asp?CID=12
>
>A typical r12 --> r134a conversion does not require you to drain the
>oil -- that's what the Interdynamics video on the conversion says.
>Doing so takes extra time and may introduce dirt and moisture into the
>system. You may want to consider draining/flushing when you need to
>open up the system for other work like replacing the compressor if
>ever.
>
>Actually, you can contact Interdynamics about these questions. But
>check their FAQ and how-to videos first. Let us know if you do.
>
>Consumer Assistance:
>Have you tried our Frequently Asked Questions (FAQ) section?
>CONSUMER@ID-USA.COM
>888-318-5454
>
>
>
>
>geronimo wrote:
>> Before I do it, I am thinking it would be good to drain out at least
>> some of the old mineral lubricant. What are the low points where there
>> are fittings I can take apart to drain? bottom fitting on condenser?
>> receiver/dryer? I figure whatever is the low point should be where
>> most of the oil has collected. Don't know how to get to fittings on
>> the evaporator....would oil drain out from there?
>>


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Old 02 Sep 2006, 12:10 am   #7 (permalink)
johngdole@hotmail.com
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Default Re: What are normal R134 pressures?

Yeah, I talked about the ratio but didn't mention the numbers. Here are
the ones for 92-96 (don't have 84-88):

Receiver .34 oz
Condenser: 1.4oz
Evaporator: 1.4oz
Compressor: 4.9oz

The total freon/oil charge is on the sticker for each production run
and would likely be different even slightly from time to time.

Interdynamics says their R134a with oil charge has the right ratio.
Unless you have major oil leaks from the system beside the oil mixed in
the freon, it might be ok just to use the standard freon/oil charge.
This is a question you can check with Interdynamics using their
customer service number/email.


geronimo wrote:
> OK, the website answers the questions not specific to a particular
> car. Mines' a 1988 Camry 3SFE, 4-cyl. I would like to have an idea
> how many ounces of R134a and how many oz of ester oil I will need to
> put in. I think this varies from car to car? I will be starting with
> an evacuated system but with mineral oil still in. Seems like mineral
> oil left in would take up space in the system, allowing less R134a and
> oil for the recharge....but it doesn't significantly reduce the
> recharge volume if a lot or all of the old oil is left in? I looked
> all over for a sticker stating the original R12 refrigerant charge,
> but could not find any, so I don't know what to expect should go in if
> all is going right. The Haynes manual doesn't say much at all on the
> AC!
>
> Thanks, Geronimo


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Old 02 Sep 2006, 09:39 am   #8 (permalink)
Daniel
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Default Re: What are normal R134 pressures?

geronimo wrote:
> OK, the website answers the questions not specific to a particular
> car. Mines' a 1988 Camry 3SFE, 4-cyl. I would like to have an idea
> how many ounces of R134a and how many oz of ester oil I will need to
> put in.

============================
You know if you just refilled with R-12 you would have no concerns
about seal or lubricant compatibility and wind up with a system that
cools more efficiently.
R134a systems were designed with larger condensors to compensate for
the reduced cooling capacity of the more environmentally friendly
refrigerant.
Ck eBay for R-12, and for online inexpensive licensing:
http://www.macsw.org/

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Old 03 Sep 2006, 06:29 am   #9 (permalink)
geronimo
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Default Re: What are normal R134 pressures?


Thanks....all helpful info, but the sticker that had the freon charge
info is gone. This info isn't in the Haynes manual, and so I am in the
dark about how refrigerant and oil should go in, assuming I leave the
old mineral oil in the system.


On 2 Sep 2006 07:39:18 -0700, "Daniel" <nospampls2002@yahoo.com>
wrote:

>geronimo wrote:
>> OK, the website answers the questions not specific to a particular
>> car. Mines' a 1988 Camry 3SFE, 4-cyl. I would like to have an idea
>> how many ounces of R134a and how many oz of ester oil I will need to
>> put in.

>============================
>You know if you just refilled with R-12 you would have no concerns
>about seal or lubricant compatibility and wind up with a system that
>cools more efficiently.
>R134a systems were designed with larger condensors to compensate for
>the reduced cooling capacity of the more environmentally friendly
>refrigerant.
>Ck eBay for R-12, and for online inexpensive licensing:
>http://www.macsw.org/


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Old 03 Sep 2006, 08:08 am   #10 (permalink)
Daniel
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Default Re: What are normal R134 pressures?

geronimo wrote:
> Thanks....all helpful info, but the sticker that had the freon charge
> info is gone.

==============
There was no sticker.
Just use the sight glass.

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