# Time for an HVAC quiz



## hvaclover (Oct 5, 2008)

Ques: Evacuation to well below 200 microns is:

A] Desirable and even even mandatory to remove all moisture.

B]The lowest level system should be pumped down to because ..(describe the changes that would be detrimental to the sealed system)

C] What is an evacuation?









Winner gets a No-Prize. 
__________________
Just slow, not stupid.


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## flashheatingand (May 3, 2008)

B. Because you have several other calls waiting and it's time to get to the next job. Seriously, I don't have an answer to detrimental changes. Only thing I can guess it has to do with charging the system and some type of chemical reaction?


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## ScipioAfricanus (Sep 13, 2008)

A. is correct.

B. would cause a total vacuum which is an impossibility thereby causing untold catastrophic consequences to the very fabric of the universe itself, tearing it asunder and plunging us all into a quantum world of black holes and uncharming quarks.

C. An evacuation is what my bowels do.

Andy.


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## MALCO.New.York (Feb 27, 2008)

A Dipshiiit quiz posed by a Dipshiiit quizzer?


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## NickTech (Feb 13, 2005)

no, 500 microns (29.9"hg) is not only the manditory rate, but it is the pressure at with water will boil at -12 deg f. 
anything lower will not cause any problems but just a waste of time. it is not possible to over evacuate a system!
EPA mandates all vacuum pumps pull down to min. of 500 microns.
evacuation is the dehydration of a system by the use of a vacuum pump to remove water and water vapor by dropping the boiling point.
i'm not only smart, im good looking too!..............where is my "no-prize"


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## hvaclover (Oct 5, 2008)

flashheatingand said:


> B. Because you have several other calls waiting and it's time to get to the next job. Seriously, I don't have an answer to detrimental changes. Only thing I can guess it has to do with charging the system and some type of chemical reaction?


Gotta answer the whole question.


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## hvaclover (Oct 5, 2008)

ScipioAfricanus said:


> A. is correct.
> 
> B. would cause a total vacuum which is an impossibility thereby causing untold catastrophic consequences to the very fabric of the universe itself, tearing it asunder and plunging us all into a quantum world of black holes and uncharming quarks.
> 
> ...


No. Your bowels void, not evacuate. There is no correlation with quantum mechanics.


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## hvaclover (Oct 5, 2008)

MALCO.New.York said:


> A Dipshiiit quiz posed by a Dipshiiit quizzer?



I know that interview by heart and love the hell out of it.

I been funin' 'ya this time.

I am a HUGE Bruce Lee fan. I just threw some **** at you only in fun cause I studied Okinawan :thumbsup:

No more wise cracks about Bruce.I promise.

Now let's go harass the the Korean Stylists:laughing:


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## hvaclover (Oct 5, 2008)

NickTech said:


> no, 500 microns (29.9"hg) is not only the manditory rate, but it is the pressure at with water will boil at -12 deg f.
> anything lower will not cause any problems but just a waste of time. it is not possible to over evacuate a system!
> EPA mandates all vacuum pumps pull down to min. of 500 microns.
> evacuation is the dehydration of a system by the use of a vacuum pump to remove water and water vapor by dropping the boiling point.
> i'm not only smart, im good looking too!..............where is my "no-prize"


You failed to make a choice.

Si have to say your answer is incorrect.

This is not a crank quiz. The question comes from leading hvac source and a nationally recognized hvac mfg.


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## hvaclover (Oct 5, 2008)

step up and give it a shot...


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## kevjob (Aug 14, 2006)

you have a test coming up?:blink:


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## NickTech (Feb 13, 2005)

A. False
B. 500 micron (29.9" hg)/ no detrement-overevacuation is impossible
C. evacuation is the dehydration of a system by the use of a vacuum pump to remove water and water vapor by dropping the boiling point.

Well if i'm incorrect then the thousands of students i've trained are incorrect as well as the EPA and RSES (my sources)


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## hvaclover (Oct 5, 2008)

NickTech said:


> A. False
> B. 500 micron (29.9" hg)/ no detrement-overevacuation is impossible
> C. evacuation is the dehydration of a system by the use of a vacuum pump to remove water and water vapor by dropping the boiling point.
> 
> Well if i'm incorrect then the thousands of students i've trained are incorrect as well as the EPA and RSES (my sources)



you may only pick one.

your response "no detriment-over evacuation is impossible" is not accurate.


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## flashheatingand (May 3, 2008)

hvaclover said:


> Gotta answer the whole question.


Ok, I think I have the answer to the question about why one doesn't want to evacuate way too low.

The reason, when approaching the perfect vaccum level, you will boil the refrigerant oil which will result in vapors in the line.

I fancy myself a guru of such matters. 

Honestly, I just googled evacuating refrigerant lines, and I read something in regards to the vapor.


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## hvaclover (Oct 5, 2008)

So does Fat Eddy...


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## oldguy2 (Jan 7, 2009)

i choose D: impossible 
a perfect vacuum is only possible in outer space
like the space between my ears


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## beenthere (Mar 5, 2009)

NickTech said:


> EPA mandates all vacuum pumps pull down to min. of 500 microns.


Wha section is that mandate in.


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## beenthere (Mar 5, 2009)

oldguy2 said:


> i choose D: impossible
> a perfect vacuum is only possible in outer space
> like the space between my ears


Even outer space is not a perfect vacuum.


Some inner spaces, may be though.


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## NickTech (Feb 13, 2005)

min evac. level mandated by epa on vacuum pumps are 500 microns, even if you could pull down to 200 microns the vacuum would only be 29.91"hg. vacuum pump oil has a boiling point under atmospheric conditions between 721-1004 deg f,and will not vaporize at that point under that vacuum.


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## NickTech (Feb 13, 2005)

section 608 of the federal clean air act, under prescrided evac. rate. (EPA.gov)


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