Re: [MBZ] Pressure and volume

[Rick Knoble via Mercedes]

I work afternoons. Just unwinding from work. Sleep in five..four..three... z

Rick
  Original Message
From: Meade Dillon via Mercedes
Sent: Monday, July 17, 2017 2:01 AM
To: Mercedes Discussion List
Reply To: Mercedes Discussion List
Cc: Meade Dillon
Subject: Re: [MBZ] Pressure and volume


3 a.m. snack time, I failed to eat enough dinner tonight.  Back to bed in a
bit...

How about you?

-
Max
Charleston SC

On Mon, Jul 17, 2017 at 2:58 AM, Rick Knoble via Mercedes <
mercedes@okiebenz.com> wrote:

> You are up late/early.
>
>
>
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Re: [MBZ] Pressure and volume

[Meade Dillon via Mercedes]

3 a.m. snack time, I failed to eat enough dinner tonight.  Back to bed in a
bit...

How about you?

-
Max
Charleston SC

On Mon, Jul 17, 2017 at 2:58 AM, Rick Knoble via Mercedes <
mercedes@okiebenz.com> wrote:

> You are up late/early.
>
>
>
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Re: [MBZ] Pressure and volume

[Rick Knoble via Mercedes]

You are up late/early.

Rick
  Original Message  
From: Meade Dillon via Mercedes
Sent: Monday, July 17, 2017 1:53 AM
To: Mercedes Discussion List
Reply To: Mercedes Discussion List
Cc: Meade Dillon
Subject: Re: [MBZ] Pressure and volume

Bravo!

-
Max
Charleston SC
‎
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Re: [MBZ] Pressure and volume

[Meade Dillon via Mercedes]

Bravo!

-
Max
Charleston SC

On Mon, Jul 17, 2017 at 12:19 AM, clay via Mercedes 
wrote:

> I took her for a longer drive.  Not as hot today, but was cold enough to
> make the cabin chilly.  As it cooled off this evening, I had to adjust the
> ACC up and it was still rather chill.
>
>
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Re: [MBZ] Pressure and volume

[clay via Mercedes]

I took her for a longer drive.  Not as hot today, but was cold enough to make 
the cabin chilly.  As it cooled off this evening, I had to adjust the ACC up 
and it was still rather chill.

clay

> On Jul 16, 2017, at 12:57 AM, fmiser via Mercedes  
> wrote:
> 
>> clay wrote:
> 
> 
>> The IR probe was not used to measure at those places specified.
> 
> Even just using your hand can work.  I don't think I would touch
> the condenser inlet for very long. It can be hot enough to
> _hurt_.  But evaporator inlet and outlet temp can be compared by
> touch.
> 
>> I have not tried the rest pressure test.
> 
> You hadn't said and I wanted to be clear. *smiles*
> 
> Usually I see low side pressures very low when it's
> under-charged.  Unless the low-pressure switch is bypassed, this
> means the compressor doesn't run for very long before shutting off.
> 
> Full disclosure - I have done little with the Mercedes AC.  Lots
> with Chevy and some with Ford.
> 
>> I did take the car out for some short (under 10 mile) trips and
>> was pretty impressed with cabin temps and cooling.
> 
> Even a little refrigerant will provide some cooling.  If the
> outside temperature isn't Poos or Bob Rentfro hot it might be
> enough.  And driving, with lots of air flowing through the
> condenser, makes it easy for the air conditioner.  
> 
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Re: [MBZ] Pressure and volume

[fmiser via Mercedes]

> clay wrote:


> The IR probe was not used to measure at those places specified.

Even just using your hand can work.  I don't think I would touch
the condenser inlet for very long. It can be hot enough to
_hurt_.  But evaporator inlet and outlet temp can be compared by
touch.

> I have not tried the rest pressure test.

You hadn't said and I wanted to be clear. *smiles*

Usually I see low side pressures very low when it's
under-charged.  Unless the low-pressure switch is bypassed, this
means the compressor doesn't run for very long before shutting off.

Full disclosure - I have done little with the Mercedes AC.  Lots
with Chevy and some with Ford.

> I did take the car out for some short (under 10 mile) trips and
> was pretty impressed with cabin temps and cooling.

Even a little refrigerant will provide some cooling.  If the
outside temperature isn't Poos or Bob Rentfro hot it might be
enough.  And driving, with lots of air flowing through the
condenser, makes it easy for the air conditioner.  

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Re: [MBZ] Pressure and volume

[clay via Mercedes]

Ah, useful data

I was running the engine with the manifold on and the service line feeding goo. 
   I have a chart that lists both high and low side at specific temp in f and 
C.   The system was showing pressures consistent with the chart, but the charge 
was low.   The IR probe was not used to measure at those places specified.

I have not tried the rest pressure test.  Figured it would show what it would 
but that would not be indicative of useful data.  I do know how much goo was 
injected, as I have evacuated the system, such that there should be nothing 
left inside prior to beginning the charging.  I should be shy 24oz.

I did take the car out for some short (under 10 mile) trips and was pretty 
impressed with cabin temps and cooling.

clay



> On Jul 15, 2017, at 12:26 PM, fmiser via Mercedes  
> wrote:
> 
>> clay wrote:
> 
>> I evacuated the system once more (it had been tested overnight)
>> and did a refill.  Well, sort of.  It calls for 3.3# of R12.
>> There is a pressure/temperature chart that gives pressures based
>> on outside temp.  Using that, I reached the required pressures,
>> but am short on volume? 
> 
> At rest pressure CANNOT be used to figure out how much is in the
> system.  Once there is about 20% change, the at-rest pressure will
> match the chart.  It won't change until thy system is
> over-charged.  That's the nature of gas. (not gasoline/petrol)
> 
> With the compressor running, looking at the low side pressure can
> give a pretty good clue as to the change.  The high side doesn't
> tell much about charge.
> 
> Weight is the most consistent way to determine change.
> 
> That's hard to do on an partly-changed system 'cause it's hard to
> weigh what is inside.  Without a machine to remove it all, (and
> scrub it clean and weigh it before putting it back in) the only
> way I know is to monitor temperatures in the evaporator. Checking
> inlet and outlet temperatures can be enough.  A no-contact IR
> thermometer is handy - but remember most of those are calibrated
> for black, not aluminum, surface.
> 
> Out of the compressor should be hot.  Out of the condenser should
> be quite warm.  After the expansion valve and inlet to the
> evaporator should be cold.  Out of the evaporator should be about
> the same or a bit colder.
>  


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Re: [MBZ] Pressure and volume

[Kaleb C. Striplin via Mercedes]

That's why I love having an ac machine. I pull it out, and charge with the 
correct amount by weight.

Sent from my iPhone

On Jul 15, 2017, at 2:26 PM, fmiser via Mercedes  wrote:

>> clay wrote:
> 
>> I evacuated the system once more (it had been tested overnight)
>> and did a refill.  Well, sort of.  It calls for 3.3# of R12.
>> There is a pressure/temperature chart that gives pressures based
>> on outside temp.  Using that, I reached the required pressures,
>> but am short on volume? 
> 
> At rest pressure CANNOT be used to figure out how much is in the
> system.  Once there is about 20% change, the at-rest pressure will
> match the chart.  It won't change until thy system is
> over-charged.  That's the nature of gas. (not gasoline/petrol)
> 
> With the compressor running, looking at the low side pressure can
> give a pretty good clue as to the change.  The high side doesn't
> tell much about charge.
> 
> Weight is the most consistent way to determine change.
> 
> That's hard to do on an partly-changed system 'cause it's hard to
> weigh what is inside.  Without a machine to remove it all, (and
> scrub it clean and weigh it before putting it back in) the only
> way I know is to monitor temperatures in the evaporator. Checking
> inlet and outlet temperatures can be enough.  A no-contact IR
> thermometer is handy - but remember most of those are calibrated
> for black, not aluminum, surface.
> 
> Out of the compressor should be hot.  Out of the condenser should
> be quite warm.  After the expansion valve and inlet to the
> evaporator should be cold.  Out of the evaporator should be about
> the same or a bit colder.
> 
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Re: [MBZ] Pressure and volume

[fmiser via Mercedes]

> clay wrote:

> I evacuated the system once more (it had been tested overnight)
> and did a refill.  Well, sort of.  It calls for 3.3# of R12.
> There is a pressure/temperature chart that gives pressures based
> on outside temp.  Using that, I reached the required pressures,
> but am short on volume? 

At rest pressure CANNOT be used to figure out how much is in the
system.  Once there is about 20% change, the at-rest pressure will
match the chart.  It won't change until thy system is
over-charged.  That's the nature of gas. (not gasoline/petrol)

With the compressor running, looking at the low side pressure can
give a pretty good clue as to the change.  The high side doesn't
tell much about charge.

Weight is the most consistent way to determine change.

That's hard to do on an partly-changed system 'cause it's hard to
weigh what is inside.  Without a machine to remove it all, (and
scrub it clean and weigh it before putting it back in) the only
way I know is to monitor temperatures in the evaporator. Checking
inlet and outlet temperatures can be enough.  A no-contact IR
thermometer is handy - but remember most of those are calibrated
for black, not aluminum, surface.

Out of the compressor should be hot.  Out of the condenser should
be quite warm.  After the expansion valve and inlet to the
evaporator should be cold.  Out of the evaporator should be about
the same or a bit colder.

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Re: [MBZ] Pressure and volume

[clay via Mercedes]

It is never that easy…

SDL has a non operational compressor, or it at least will not kick on, and the 
aux cooling fan does not kick on either.  I only got the car to suck up about 
7oz of duster air, so that both hi and low are sitting at 70psi

clay


> On Jul 14, 2017, at 3:58 PM, clay via Mercedes  wrote:
> 
> I am doing the AC recharge in the w126 cars today and have had an interesting 
> learning curve.
> 
> FIRST, check to make sure the system is complete with Schrader valves!  High 
> side did not have one and after charging the AC and getting nice cold air, I 
> tried to unhook the manifold.  It all came spewing out in a great hurry.  
> Must be why PO had installed R134 fittings.  I am going to be swabbing oily 
> dye mist from all manner of items for a long while.
> 
> I evacuated the system once more (it had been tested overnight) and did a 
> refill.  Well, sort of.  It calls for 3.3# of R12.  There is a 
> pressure/temperature chart that gives pressures based on outside temp.  Using 
> that, I reached the required pressures, but am short on volume?   Oil 
> injected was only 2.0oz, and Duster cans gave a bit over a pound.  Vent temps 
> are only 60f.  
> 
> Do I proceed with intalling the rest of the charge to at least 3.0#?
> 
> At the moment I am doing the vac hold test on the other car prior to recharge.
> 
> 
> clay 
> 
> 1974 450sl -  Frosch - Two tone green
> 1986 SDL - Polei
> 1982 300 SD - Allen
> 
> retired models-
> 2002 s430 - Victor, a Stately & well tailored crap
> 1976 300D - Blei Vanst - it looks silvery
> 1972 220D - Gump - She was green, simple and ran
> 1995 E300D - Gave her life to save me against a Dame in a SUV
> POS 1987 SDL - Beware Nigerian Scammers
> 
> 
> 
> 
> 
> 
> 
> 
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> 
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> 
> To Unsubscribe or change delivery options go to:
> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
> 


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Re: [MBZ] Pressure and volume

[Kaleb C. Striplin via Mercedes]

I always charge to 80% or r12 amount. 

Sent from my iPhone

> On Jul 14, 2017, at 5:58 PM, clay via Mercedes  wrote:
> 
> I am doing the AC recharge in the w126 cars today and have had an interesting 
> learning curve.
> 
> FIRST, check to make sure the system is complete with Schrader valves!  High 
> side did not have one and after charging the AC and getting nice cold air, I 
> tried to unhook the manifold.  It all came spewing out in a great hurry.  
> Must be why PO had installed R134 fittings.  I am going to be swabbing oily 
> dye mist from all manner of items for a long while.
> 
> I evacuated the system once more (it had been tested overnight) and did a 
> refill.  Well, sort of.  It calls for 3.3# of R12.  There is a 
> pressure/temperature chart that gives pressures based on outside temp.  Using 
> that, I reached the required pressures, but am short on volume?   Oil 
> injected was only 2.0oz, and Duster cans gave a bit over a pound.  Vent temps 
> are only 60f.  
> 
> Do I proceed with intalling the rest of the charge to at least 3.0#?
> 
> At the moment I am doing the vac hold test on the other car prior to recharge.
> 
> 
> clay 
> 
> 1974 450sl -  Frosch - Two tone green
> 1986 SDL - Polei
> 1982 300 SD - Allen
> 
> retired models-
> 2002 s430 - Victor, a Stately & well tailored crap
> 1976 300D - Blei Vanst - it looks silvery
> 1972 220D - Gump - She was green, simple and ran
> 1995 E300D - Gave her life to save me against a Dame in a SUV
> POS 1987 SDL - Beware Nigerian Scammers
> 
> 
> 
> 
> 
> 
> 
> 
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> 
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> 
> To Unsubscribe or change delivery options go to:
> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
> 


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Re: [MBZ] Pressure and volume

[Mitch Haley via Mercedes]

I've seen conversion ratios given at 75%, 80%, or 90%.
I'd start out with 3/4 the weight of the specified R12 charge and go up slowly 
from there.

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[MBZ] Pressure and volume

[clay via Mercedes]

I am doing the AC recharge in the w126 cars today and have had an interesting 
learning curve.

FIRST, check to make sure the system is complete with Schrader valves!  High 
side did not have one and after charging the AC and getting nice cold air, I 
tried to unhook the manifold.  It all came spewing out in a great hurry.  Must 
be why PO had installed R134 fittings.  I am going to be swabbing oily dye mist 
from all manner of items for a long while.

I evacuated the system once more (it had been tested overnight) and did a 
refill.  Well, sort of.  It calls for 3.3# of R12.  There is a 
pressure/temperature chart that gives pressures based on outside temp.  Using 
that, I reached the required pressures, but am short on volume?   Oil injected 
was only 2.0oz, and Duster cans gave a bit over a pound.  Vent temps are only 
60f.  

Do I proceed with intalling the rest of the charge to at least 3.0#?

At the moment I am doing the vac hold test on the other car prior to recharge.


clay 

1974 450sl -  Frosch - Two tone green
1986 SDL - Polei
1982 300 SD - Allen

retired models-
2002 s430 - Victor, a Stately & well tailored crap
1976 300D - Blei Vanst - it looks silvery
1972 220D - Gump - She was green, simple and ran
1995 E300D - Gave her life to save me against a Dame in a SUV
POS 1987 SDL - Beware Nigerian Scammers








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