Vacuum pump CFM's?

[mooka]

Whats a usuable CFM for a vacuum pump for someone wanting to start a smaller a/c repair shop?
5.0 is what I have been told, but would like the input from the experts:)
Thanks
Tim

[The MG Pony]

2cfm is plenty for smaller systems.

[The Viking]

The size of the pump is only part of the story....

One of the vacc pump manufacturers once told me that if you take a 5 cfm pump, attach it to an 1/4" hose through a manifold and then another 1/4" hose before it go through a schrader valve, well then you are left with the capacity of less than 1 cfm.

The only time a bigger pump will be better is when you have large systems to vacc out and connect the pump through large bore hoses or pipes.

(Tip, use a shraeder removal tool to lift the schrader out of the way as well)

But remember to get yourself a good vacc gauge, that's where you want to spend the extra cash you saved on the pump!

[The MG Pony]

These two are nice tools and I love em.

[US Iceman]

I agree with The Vikings comments.

It's not so much the size of the pump as it is the hose diameter. I normally used 1/2" to 5/8" copper tubing from the vacuum pump to the system connection.

And the other issue is the volume of the system itself. A small system may only require a small vacuum pump.

On the other hand, I have worked on large R-22 systems where we had either a very large vacuum pump with cold traps, or many smaller vacuum pumps hooked up to select locations in the system.

[paul_h]

I just bought myself a 4cfm one. Seemed like a good compromise in price/performance for small units.
I would buy a larger one if doing commercial stuff, but the size is fine for domestic split air cons and small fridges.

I've got to buy myself one of those in line schrader core removers. ;)

[The MG Pony]

I got a 1.5 CFM 38 Micron one from ebay :) May I highly suggest you get a supco VG64 Vacuum gauge, extremely use full tool.

[paul_h]

Yeah, those vacuum gauges look OK. No one in australia sells them though.
After searching through the heaps for sale on US ebay, I found one that will ship outside of the USA. :(
I'll hit them up for a postage quote.

[The MG Pony]

Ebay, you'll get them some what cheap, well worth it.

[paul_h]

What do you normally evacuate down to when using this gauge anyway? Do you feel running the extra 1/4 guage hose line makes a difference in the length of time to get that vacuum?
I'm well used to going to ebay for my gear. :D
I've bought pipe benders, vac pump, spare 72" gauge lines and 80mm gauges, masonary 55-75mm hole saws, a bunch of hand tools, oxy acetylene set, cheap reliable megger, Fluke mulitimeter direct from USA, electronic leak detector and capacitor tester from china, bearing puller set, the list goes on. I spent about $1600 on ebay this year, all about half retail prices here, getting gear for myself before I start my own business.
If only I could buy a cheap oil less reclaimer from there:(
Damn you 110v ac supply in USA, nothing there for us people on 240v.
New reclaimers here list for au$2k, and the second hand market doesn't exist. US ebay has heaps for only us$300.

[The MG Pony]

I go untill it goes down no more, then hold it there for a bit, then isolate the pump and watch for rise, at very min you should all ways go down to or lower then 500 microns.

[Samarjit Sen]

For larger systems what capacity of vaccum pump would you advice.

[robin r33 gtr]

I use a 6 cfm robinair vac pump and as i find they work so well i would now not use anything else.

[The MG Pony]

They say a 1.5cfm is good up to a 20Ton system!

Wether or not I'd put that to practice is another story, I'd say from .5 to 30 use a good high quality 4cfm one.

and from 30 to 100 use a good 6cfm one

[sepp]

I just bought myself a 4cfm one. Seemed like a good compromise in price/performance for small units.
I would buy a larger one if doing commercial stuff, but the size is fine for domestic split air cons and small fridges.

I've got to buy myself one of those in line schrader core removers. ;)

Hi Paul_h

I'm in Melbourne and only do car A/C (currently using an used, large commercial A/C compressor for a vacuum pump). Looking at buying a two stage commercial.
Where did you buy yours and how much - if that is not too personal.
US vac pumps seem so much better value than what i saw here.

Your thought would be much appreciated.

Cheers

[nike123]

If you buying vacuum pump, you should also buy electronic vacuum meter to be able to know when your work is done properly. If you has had it before, then you would know that that A/C compressor could not pull even near decent vacuum required for properly done job.

[Grizzly]

A lot of the guys seem to like to use electronic vacuum gauges.

Although I have got one I rarely use it.

I much prefer to use a Torr Gauge the ones that work issue.
Start at 20 torr so you have to wait forever before you get an indication of what is going on.

So I tend to use my own which starts at 50 torr.

In fairness as has been stated the size of the equipment needed is relevant to the size of the system under vacuum!

So Mooka to answer your question.
Look at what size of systems you will be working on.

And also what you can afford!!

If Canada is like the U.S. they should be pretty good value. (Like Paul H i Ship kit from U.S. via Ebay.com )

[paul_h]

Hi Paul_h

I'm in Melbourne and only do car A/C (currently using an used, large commercial A/C compressor for a vacuum pump). Looking at buying a two stage commercial.
Where did you buy yours and how much - if that is not too personal.
US vac pumps seem so much better value than what i saw here.

Your thought would be much appreciated.

CheersYou can get cheap vac pumps on ebay.au for $210, (i got my from tritrade299) or robinaire ones from actrol for ~$270.
Robinair get them made cheap in china now, so they are virtually identicle to the ebay ones
Actrol occasionally has the robinaires cheap.

Last time I went to actrol I ended up buying an inficon oil-less reclaimer for $900, pretty cheap for normal australian prices. I personally would have bought the $270 vac pump from them too if I already hadn't bought the ebay one, the price is good considering longer warranty and being easier to return.
I agree with everyone saying get a decent vacuum gauge. Time is money, there's no point running a vac pump for 30min if you're not getting a decent vacuum, and there's no way to tell without a decent vac gauge.

[techie]

hey man
a h 5 is more than enough but personaaly i believe bigger is beter when it comes to vacuum pumps but a 5 cfm is perfect

[norfolkboy]

hi all,
does any one know of and can recomend a company that will overhaul vac pumps in the uk. i seem to have a bit of a colllection of old pumps that only need a bit of tlc. it seems a shame to scrap them.
many thanks.

[Chunk]

hi all,
does any one know of and can recomend a company that will overhaul vac pumps in the uk. i seem to have a bit of a colllection of old pumps that only need a bit of tlc. it seems a shame to scrap them.
many thanks.

Hi Norfolkboy

I googled vacuum pump repair and it bought up hundreds of places,so have a look and see if theres anyone near you:cool::).