Air Conditioning Malfunction

[Ext User(Clockmeister)]

"Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
news:w_Sff.22057$Hj2.21839@news-server.bigpond.net.au...
> Clockmeister wrote:
>> "Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
>> news:tnQff.21914$Hj2.9962@news-server.bigpond.net.au...
>>
>>>David Springthorpe wrote:
>>>
>>>>On Sun, 20 Nov 2005 09:21:38 +1000, "The Red Krawler"
>>>><redkrawler@hotmail.com>
>>>>
>>>> >.....Probably best to take it to a pro :)
>>>>
>>>>In my case, I would say yes.....
>>>
>>>Nope, what you have to do is simply understand and fix it
>>>yourself.
>>>
>>>Really not that hard, A/C is so piss easy I'd inflict it
>>>on primary skooll kids.
>>
>> Back to school for you then.
>
> LOL, my A/C actually works, though.
>

Plenty have problems properly diagnosing A/C faults, you know the kinds that
can't be fixed with a "service".

> You have a serious problem on this issue???????

Neh, just ****ing with you ;-)

> Or making $ from it?

I get to fix other peoples ****ups if that is what you mean. Diagnosing
actual A/C faults seems to be beyond the capabilities of most technicians
let alone wannabe's ;-)

[Ext User(Clockmeister)]

"ken" <kkerrison@ozemail.com.au> wrote in message
news:1132456854.333864.254330@g47g2000cwa.googlegr oups.com...
> Hardly relevant this time of year but I put in my usual advice on a/c:
> If your car fogs up (more likely in winter) turn on your air
> conditioning. It will clear the fog in no time.

Yep A/C + Heat = No Fog

> More importantly, this practice will cause you to run your a/c several
> times during the winter so that an obscure carbon bush will continue to
> retain your gas rather than losing it in a flash.
>

Yep, in fact on a lot of Euro stuff the A/C compressor is switched on when
reverse is selected for that very reason.

[Ext User(John_H)]

Clockmeister wrote:

>
>"John_H" <john4271@hotmail.com> wrote in message
>news:gd20o1162g12tcu5vo4clipp67ng3u42a3@4ax.com.. .
>> Clockmeister wrote:
>>>
>>>"Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
>>>news:OxOff.21831$Hj2.4640@news-server.bigpond.net.au...
>>>>
>>>> Is there fluid visable in the receiver dryer? (should go from bubbly to
>>>> clear when the compressor kicks in)
>>>
>>>Nope, not on R134a systems. You should see bubbles moving if it is working
>>>properly.
>>
>> Not in my limited experience with R134A.... Admittedly though, my own
>> personal contribution to DuPont's coffers hasn't been a large one. :)
>>
>> R134A systems generally don't have sight glasses, but I've recharged
>> the odd one where the the replacement aftermarket receiver drier did
>> have a sight glass. No bubbles whatsover with the correct (weighed)
>> charge. Last one was only a couple of days ago.
>
>The main reason why sight glasses were deleted from R134a systems is to
>prevent overfilling.

Sight glasses were also deleted from the last of the R12 systems for
exactly the same reason -- to force those servicing the system to
measure the charge. Most systems have always specified a correct
charge weight, most servicemen couldn't be stuffed reading the manual!

Charging a system solely by looking at the sight glass was never the
the best way to do the job.

>It is very normal to have bubbles in the sight glass of a R134a system.

It's normal to see bubbles in an operational R12 system as well -- it
indicates a reduced charge. As I previously stated, none of the few
R134A systems I've recharged which have had sight glasses have had
bubbles when initially filled with the correct amount of refrigerant
(measured by weight). I also doubt if any would ex factory.

>
>> AFAIK the bit about seeing bubbles is part of the bullshit they used
>> to feed those who retrofitted R12 systems -- presumably to avoid the
>> system throwing out on the standard high pressure switch due to the
>> higher operating pressure of R134A.
>
>It's because retrofitted systems don't take the same amount of gas, about
>80% of the volume of R12. A properly charged R134a system is likely to
>exhibit bubbles, so charging by sightglass was no longer possible.

The bubbles don't indicate whether or not a different refrigerant
requiress a different amount to do the job. The absence of bubbles
merely indicates that the gas to liquid phase is being completed.

A precise charge using the sight glass was never possible since
temperatures also play a part. In my experience, particularly with
R12, a measured charge will invariably take the system beyond the
point where the bubbles disappear (ie tending towards an overcharge by
around 200g seems to be the norm). No doubt this is also designed to
allow for a certain amount of unavoidable loss -- via molecular
diffusion, less than perfect compressor seals, etc.

>
>> Even basic text book theory suggests that any gas which doesn't
>> liquify will do SFA for the refrigeration cycle.
>>
>
>Overgassing reduces performance and puts extra stress on components.

Sure it does, since it inhibits the complete cycle... ie gas to liquid
to gas. Similarly if there's not enough refrigerent to complete the
gas to liquid cycle then efficiency is also affected.

Bubbles are a sure sign that the gas to liquid phase isn't being
completed. Same as a hyperthetical sight glass on the low pressure
side would indicate an overcharge by the presence of liquid.

So far you've given us no sound reason why there should be bubbles in
an R134A system with an optimum charge.

--
John H

[Ext User(The Red Krawler)]

> The main reason why sight glasses were deleted from R134a systems is to
> prevent overfilling.
> It is very normal to have bubbles in the sight glass of a R134a system.
> It's because retrofitted systems don't take the same amount of gas, about
> 80% of the volume of R12. A properly charged R134a system is likely to
> exhibit bubbles, so charging by sightglass was no longer possible.

Pht, use some 34m/SP34E you suckers.


NB - Agree completely with bubbles in the sight glass.

[Ext User(The Raven)]

"David Springthorpe" <david.springthorpe@idx.com.au> wrote in message
news:5abvn11slemrinap28kvjge3nsaio1bcgv@4ax.com...
>I was driving my Astra back from the Central Coast to Sydney yesterday with
>the
> fan and cold both on full (I'd been walking in Bouddi NP and the car had
> gotten
> hot parked) when after a while I noticed that it wasn't cold anymore. I've
> now
> checked it again this morning and it's still not working. I checked all
> the
> relevant fuses, and yes, I did actually have the air conditioning switch
> on (it
> lighted up okay). What else could have gone wrong please ?


If it's like Australian built Holdens, the air conditioning compressor will
not activate if the gas pressure had dropped below a certain point. It's a
safety feature to prevent people ruining their compressors.


--
The Raven
http://www.80scartoons.co.uk/batfinkquote.mp3
** Now I will bring chaos to the world!

[Ext User(Patrick Young)]

Clockmeister wrote:

> It's because retrofitted systems don't take the same amount of gas, about
> 80% of the volume of R12. A properly charged R134a system is likely to
> exhibit bubbles, so charging by sightglass was no longer possible.
>
>>Even basic text book theory suggests that any gas which doesn't
>>liquify will do SFA for the refrigeration cycle.
>>
>
> Overgassing reduces performance and puts extra stress on components.

R134A should not be allowed near R12 systems. Won't work, never did
and never will (learnt that the hard way).

Not that any of this worries me, I use R290, which pisses on
both R12 and R134A.

Converting an R12 system to R134A is something similiar to infant
circumcision - ie: needs death penalty, unless you work for Dupont ?

[Ext User(Clockmeister)]

"John_H" <john4271@hotmail.com> wrote in message
news:5mc0o11pkkl34m486u8ecnc4ebep59jtcn@4ax.com...
> Clockmeister wrote:
>
>>
>>"John_H" <john4271@hotmail.com> wrote in message
>>news:gd20o1162g12tcu5vo4clipp67ng3u42a3@4ax.com. ..
>>> Clockmeister wrote:
>>>>
>>>>"Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
>>>>news:OxOff.21831$Hj2.4640@news-server.bigpond.net.au...
>>>>>
>>>>> Is there fluid visable in the receiver dryer? (should go from bubbly
>>>>> to
>>>>> clear when the compressor kicks in)
>>>>
>>>>Nope, not on R134a systems. You should see bubbles moving if it is
>>>>working
>>>>properly.
>>>
>>> Not in my limited experience with R134A.... Admittedly though, my own
>>> personal contribution to DuPont's coffers hasn't been a large one. :)
>>>
>>> R134A systems generally don't have sight glasses, but I've recharged
>>> the odd one where the the replacement aftermarket receiver drier did
>>> have a sight glass. No bubbles whatsover with the correct (weighed)
>>> charge. Last one was only a couple of days ago.
>>
>>The main reason why sight glasses were deleted from R134a systems is to
>>prevent overfilling.
>
> Sight glasses were also deleted from the last of the R12 systems for
> exactly the same reason -- to force those servicing the system to
> measure the charge. Most systems have always specified a correct
> charge weight, most servicemen couldn't be stuffed reading the manual!
>
> Charging a system solely by looking at the sight glass was never the
> the best way to do the job.
>
>>It is very normal to have bubbles in the sight glass of a R134a system.
>
> It's normal to see bubbles in an operational R12 system as well -- it
> indicates a reduced charge. As I previously stated, none of the few
> R134A systems I've recharged which have had sight glasses have had
> bubbles when initially filled with the correct amount of refrigerant
> (measured by weight). I also doubt if any would ex factory.
>
>>
>>> AFAIK the bit about seeing bubbles is part of the bullshit they used
>>> to feed those who retrofitted R12 systems -- presumably to avoid the
>>> system throwing out on the standard high pressure switch due to the
>>> higher operating pressure of R134A.
>>
>>It's because retrofitted systems don't take the same amount of gas, about
>>80% of the volume of R12. A properly charged R134a system is likely to
>>exhibit bubbles, so charging by sightglass was no longer possible.
>
> The bubbles don't indicate whether or not a different refrigerant
> requiress a different amount to do the job. The absence of bubbles
> merely indicates that the gas to liquid phase is being completed.


> A precise charge using the sight glass was never possible since
> temperatures also play a part. In my experience, particularly with
> R12, a measured charge will invariably take the system beyond the
> point where the bubbles disappear (ie tending towards an overcharge by
> around 200g seems to be the norm). No doubt this is also designed to
> allow for a certain amount of unavoidable loss -- via molecular
> diffusion, less than perfect compressor seals, etc.
>
>>
>>> Even basic text book theory suggests that any gas which doesn't
>>> liquify will do SFA for the refrigeration cycle.
>>>
>>
>>Overgassing reduces performance and puts extra stress on components.
>
> Sure it does, since it inhibits the complete cycle... ie gas to liquid
> to gas. Similarly if there's not enough refrigerent to complete the
> gas to liquid cycle then efficiency is also affected.
>
> Bubbles are a sure sign that the gas to liquid phase isn't being
> completed. Same as a hyperthetical sight glass on the low pressure
> side would indicate an overcharge by the presence of liquid.
>
> So far you've given us no sound reason why there should be bubbles in
> an R134A system with an optimum charge.
>

OK, I've worked with R12 and R134a systems for over 15 years and experience
tells me it is so. I don't need no other reason.

[Ext User(Clockmeister)]

"Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
news:CuZff.22379$Hj2.21380@news-server.bigpond.net.au...
> Clockmeister wrote:
>
>> It's because retrofitted systems don't take the same amount of gas, about
>> 80% of the volume of R12. A properly charged R134a system is likely to
>> exhibit bubbles, so charging by sightglass was no longer possible.
>>
>>>Even basic text book theory suggests that any gas which doesn't
>>>liquify will do SFA for the refrigeration cycle.
>>>
>>
>> Overgassing reduces performance and puts extra stress on components.
>
> R134A should not be allowed near R12 systems. Won't work, never did
> and never will (learnt that the hard way).
>
> Not that any of this worries me, I use R290, which pisses on
> both R12 and R134A.
>
> Converting an R12 system to R134A is something similiar to infant
> circumcision - ie: needs death penalty, unless you work for Dupont ?

Done correctly there is nothing wrong with retrofitting.

[Ext User(Patrick Young)]

Clockmeister wrote:
> "Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
> news:CuZff.22379$Hj2.21380@news-server.bigpond.net.au...
>
>>Clockmeister wrote:
>>
>>
>>>It's because retrofitted systems don't take the same amount of gas, about
>>>80% of the volume of R12. A properly charged R134a system is likely to
>>>exhibit bubbles, so charging by sightglass was no longer possible.
>>>
>>>
>>>>Even basic text book theory suggests that any gas which doesn't
>>>>liquify will do SFA for the refrigeration cycle.
>>>>
>>>
>>>Overgassing reduces performance and puts extra stress on components.
>>
>>R134A should not be allowed near R12 systems. Won't work, never did
>>and never will (learnt that the hard way).
>>
>>Not that any of this worries me, I use R290, which pisses on
>>both R12 and R134A.
>>
>>Converting an R12 system to R134A is something similiar to infant
>>circumcision - ie: needs death penalty, unless you work for Dupont ?
>
> Done correctly there is nothing wrong with retrofitting.

Done correctly would really require the entire system to be replaced
really.

You are looking at oil incompatibilities as well as the stuff plain
sucks, smaller molecule size..... goes awol? if the compressor does
not fail first from oil starvation due to lack of oil being carried
by the refigerant.

Sorry, you really need to look at this some more.





I only have a couple of years experience, however putting R134a (and
it's lubricants) near an R12 system makes no sense. Did you do this
to your own car?

[Ext User(Clockmeister)]

"Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
news:sWigf.23350$Hj2.10362@news-server.bigpond.net.au...
> Clockmeister wrote:
>> "Patrick Young" <patrick@hilux.ace.unsw.EDU.AU> wrote in message
>> news:CuZff.22379$Hj2.21380@news-server.bigpond.net.au...
>>
>>>Clockmeister wrote:
>>>
>>>
>>>>It's because retrofitted systems don't take the same amount of gas,
>>>>about 80% of the volume of R12. A properly charged R134a system is
>>>>likely to exhibit bubbles, so charging by sightglass was no longer
>>>>possible.
>>>>
>>>>
>>>>>Even basic text book theory suggests that any gas which doesn't
>>>>>liquify will do SFA for the refrigeration cycle.
>>>>>
>>>>
>>>>Overgassing reduces performance and puts extra stress on components.
>>>
>>>R134A should not be allowed near R12 systems. Won't work, never did
>>>and never will (learnt that the hard way).
>>>
>>>Not that any of this worries me, I use R290, which pisses on
>>>both R12 and R134A.
>>>
>>>Converting an R12 system to R134A is something similiar to infant
>>>circumcision - ie: needs death penalty, unless you work for Dupont ?
>> Done correctly there is nothing wrong with retrofitting.
>
> Done correctly would really require the entire system to be replaced
> really.
>
> You are looking at oil incompatibilities

Largely exaggerated.

as well as the stuff plain
> sucks, smaller molecule size..... goes awol?

Only if the hose hasn't been permeated with R12 for long enough, which is
rare for an R12 system given their age.

if the compressor does
> not fail first from oil starvation due to lack of oil being carried
> by the refigerant.
>

The oil is replaced and system flushed if retrofitted properly.

> Sorry, you really need to look at this some more.
>

I have thanks. I did say properly retrofitted.

>
> I only have a couple of years experience, however putting R134a (and
> it's lubricants) near an R12 system makes no sense. Did you do this
> to your own car?
>

Didn't need to. Done plenty of others though with only a couple of
compressor seal failures otherwise no problems at all.
Worked fine too, though not as efficient as a system designed for R134a.

[Ext User(springy)]

Alas, the latter is apparently what's wrong.....gues I'll put off that
new digital camera for a while.....

DS