lowering micron readings

[Randykissling]

Hi Was thinking of purchasing 3/8" vacuum hoses . I was told this would speed up evacuation and get me a lower micron reading. But the hoses will still attache to 1/4" schrader valves with 3/16" openings. Mostly work on split systems and 10 ton or less roof top units. Wonder what you guys think. Thank you
Randy

[cool runings]

Hi Was thinking of purchasing 3/8" vacuum hoses . I was told this would speed up evacuation and get me a lower micron reading. But the hoses will still attache to 1/4" schrader valves with 3/16" openings. Mostly work on split systems and 10 ton or less roof top units. Wonder what you guys think. Thank you
Randy


3/8 shared to your gauge manifold will increase the speed of the vac, slightly.

But speed is not always best. Depth of vac or a good tripple vac is better than a fast evacuation.

cool runnings

.

[Randykissling]

thanx but will I get a lower micron reading with the larger hoses?

[james10]

My tutor at college had an old manual that said an increase in hose diameter decreases the evacuation time also that every time you double the length of the hose you double the evacuation time. As regards to lowering the micron reading hose daiameter is irrelavant as time and a good vac pump are the only factors in this also as Cool Runnings said triple vac is the best way of getting a good vacuum

[cool runings]

thanx but will I get a lower micron reading with the larger hoses?


No..

You will only get a lower Micron reading if the vac pump can pull that low (and as long as the system is gas tight).

No mater what size pipe you vac with you will pull a low vacuum, but the pipe will affect the speed so if you want to vac a system in a few mins you need a hugh vac pump and hugh pipes!! If you have hours to vac out you will always achieve the same level, only time will vary!!

A tripple vac is the way to go..

cool runnings.

.

[Randykissling]

Thank you guys you have saved me a few bucks

[sedgy]

hi , just read your coments , I allways understud the vacing situation as=2 shaders valves removed 2x 1/4 lines from unit to gauges, then a 3/8 line from gauges to vac pump for maximum effect if you only got a small set of gauges= 3 x 1/4 fittings , you can fit a 1/4 femail 3/8 male addaptor to the middle 1/4 outlet to screw your 3/8 pipe to get the same effect.
any comments ?

[Brian_UK]

You can always remove the Schraeder cores to improve the vacuum experience.

[Gingerair]

I agree with Sedgy, use 4-valve manifold set with 3/8 hose for vac. Can always put remaining 2 or even 3 x 1/4 hoses on system without worrying about any restrictions.
Use 2-valve sets for taking readings, etc.

[airmate]

Hi, There are some other small basics to keep in mind for reaching good evacuation levels. Using correct size and stage of vaccum pump on different capacity, changing oil after every use to reduce contamination of pump and vaccum gauges, keeping the o rings on your manifold hoses wet with lubricant so they dont wear quickly and seal to give good vaccum levels.

[nike123]

I see lot of different answers and some misconceptions.
Check this document:
http://www.mediafire.com/?zmyztx5gnzm

[AlexLPD]

I see lot of different answers and some misconceptions.
Check this document:
http://www.mediafire.com/?zmyztx5gnzm


Huge contribution in deed... I read it and help me a lot, know am searchin for 4 way mainflod, 3/8" ... or meaby 1/2" inch... IOL

[Grizzly]

Everyone should take the time to read Nike's post.
I Quote "

Exactly how much does the size of the hoses effect conductance speed? The easy answer is BY A FACTOR OF 4! Which
doesn't mean very much unless I add this bit of information; for every 1/8 Inch increase in hose size! That's right, for every
1/8 Inch increase in hose size the conductance speed is increased by a factor of 4!"

So in simple English.
Increasing the hose size by 1/4" makes achieving your vacuum 4 times faster.
Not any lower than the pump can achieve but faster.

Nice one! Nike. ( Sorry I am not allowed to give you points at the moment. I must spread the warmth around apparently.)
Grizzly

[Magoo]

The bigger the pipe and the shortest pipe will increase flow to vac pump. Most pumps are rated on free flow rating, not flash below zero pressure.

[lana]

Hi guys,

I just wanted to share these files.

BTW : Vacuum is a very strange science, isn't it? :cool:

Cheers

PS : Sorry the file name spelling is incorrect !!!