Vacing system & JohnsonsControll V46AB Valve?

[The MG Pony]

I built a system that has a V46AB-1C in it, do I need isolate this during a vac? or can I just proceed and vac the entire system with out pulling its sensing tube out?

[star882]

Every part in a refrigeration system should be able to survive a vacuum.

[The MG Pony]

Not quite, when deep vacing you should protect parts with bellows as not to over strain them.

Any case I remembered what we did be for with the valves. We isolated them and vaced system broke vac with N2 and placed valve sense back on.

[star882]

Actually, the difference between a low vacuum (29"Hg) and a high vacuum (500 microns) is not much in terms of pressure difference.
If it can survive a low vacuum, it will most likely survive a high vacuum.

I'm not sure how else can you remove moisture from the part. Pulling a vacuum is what is normally done.

[The MG Pony]

Vacing is primarily for removing non condensible.

Frankly my brain has gone haywire lately here. It is things with gas filled bellows that are most in danger of being damaged by vacuum. thus such things if possible should be isolated or precautions taken. The valve I am using is not gas filled thus I could have left it in, but better safer then sorry. with thermal statics I have been told during deep vac to put the bulb in cold water or water with ice, I guess the reasoning is to keep pressure in the top of the bellows low as possible its self.

1:24am here so brain is shuting off now. or has all ready hard to tell now days.

[goodguy]

The MG pony,
I would say vacuum away, have done it lots of times, if in doubt ask Johnson Controls. Also here is a thought, would you pull a vacuum on a TEV? (gas charged power element)
good luck in your project.
Goodguy

[Sledge]

. It is things with gas filled bellows that are most in danger of being damaged by vacuum. thus such things if possible should be isolated or precautions taken. The valve I am using is not gas filled thus I could have left it in, but better safer then sorry. with thermal statics I have been told during deep vac to put the bulb in cold water or water with ice, I guess the reasoning is to keep pressure in the top of the bellows low as possible its self..

I have never heard of this as being a problem? Will this crack the bellows? Are they designed to only flex in one direction? I thought that the pressure in the bulb would only end up driving the valve onto the seat. I cannot remember ever experiencing a problem with this. I always thought that you could vacuum the whole system.

[The MG Pony]

I'm not sure if the engineer who was teaching me was just being neurotic or if there is an issue, either way it doesn't hurt, so simple to shove the bulbe on ice and no worries :) Though I do think Sporlan mentiond some thing about it in their PDFs.

[hvac01453]

Thinking of the pressures they survive a vacuum is only about 1 or 2 PSI in the negative isn't it????

[NH3LVR]

Thinking of the pressures they survive a vacuum is only about 1 or 2 PSI in the negative isn't it????
14.7 LBS = 29.9" if I recall correctly:)