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Point being, is this Harbor Freight vacuum pump able to draw as good a vacuum as a pro-type pump, but it takes longer getting there, or is it not able to pull as high a vacuum?
Anybody know?[/quote]
The HF pump will pull vacuum fine, but probably will not last. As in all else, you get what you pay for. The HF pump will last for a year, maybe, whereas a Robinair that you can buy off ebay will last the rest of your life.
On an a/c system you are only pulling -18 of vacuum, max, and any vacuum pump is capable of that. The question is how much hassle you are willing to put up with. As DYI it may make sense to buy a cheap one and drive to the tool store for the warranty every year. You can buy a good used Robinair for 100-125 on ebay plus 30 bucks for shipping--my experience with them is they are tanks, heavy and built to last for a lifetime.
Pay a little and lose some time, or pay a lot and have no worries. They will all do the job, it just depends on how long you want them to do that job.
The HF pump will pull vacuum fine, but probably will not last. As in all else, you get what you pay for. The HF pump will last for a year, maybe, whereas a Robinair that you can buy off ebay will last the rest of your life.
On an a/c system you are only pulling -18 of vacuum, max, and any vacuum pump is capable of that. The question is how much hassle you are willing to put up with. As DYI it may make sense to buy a cheap one and drive to the tool store for the warranty every year. You can buy a good used Robinair for 100-125 on ebay plus 30 bucks for shipping--my experience with them is they are tanks, heavy and built to last for a lifetime.
Pay a little and lose some time, or pay a lot and have no worries. They will all do the job, it just depends on how long you want them to do that job.
Most people that buy HF stuff don't use it every day. I don't see how you can assume the pump will only last a year if its bought and used once, even once a year. The reviews for the small Harbor Freight pump have been good on various forums.
Point being, is this Harbor Freight vacuum pump able to draw as good a vacuum as a pro-type pump, but it takes longer getting there, or is it not able to pull as high a vacuum?
Anybody know?
The HF pump will pull vacuum fine, but probably will not last. As in all else, you get what you pay for. The HF pump will last for a year, maybe, whereas a Robinair that you can buy off ebay will last the rest of your life.
On an a/c system you are only pulling -18 of vacuum, max, and any vacuum pump is capable of that. The question is how much hassle you are willing to put up with. As DYI it may make sense to buy a cheap one and drive to the tool store for the warranty every year. You can buy a good used Robinair for 100-125 on ebay plus 30 bucks for shipping--my experience with them is they are tanks, heavy and built to last for a lifetime.
Pay a little and lose some time, or pay a lot and have no worries. They will all do the job, it just depends on how long you want them to do that job.[/quote]
if he were opening up an a/c shop and going to be doing it everyday, then i would never have recommended the HF pump. but since he is just going to do his a/c system, and perhaps that of his friends and family, he might use the pump 5 or 6 times per year at best, and even that will taper off, so the HF pump will last quite a long time, as long as he properly maintains the pump, and perhaps even if he doesnt.
I am a retired profesional so my tools/equipment are overkill for what you need however;Harbor freight does have a vac-pump that will work for the ocaisional user.I use a Blue Point by Snap-on & bought it in 1976 & it works like new after all the years.This is not a rotary pump like a fast vac
that the market has seemed to prefer these days,it actuall is a compresor itself like from a refrigerator.Now with that being said you can build your own from a used compresor very cheap and it should last for years.It will pull down to 29 inches of vacum easily and takes less than a half hour to assemble once all the parts are ther.Good Luck!
I have a double-walled glass column of 25cm height ,9.3cm inner dia and 10cm outer dia.The annular space between the walls have to be maintained under vacuum to minimise heat losses.So,guys sugesst me which pump to use ?
You need a pretty good vacuum pump to draw down to 500 micron or less. That's virtually almost a perfect vacuum. Most of the cheapo vacuum pumps can do maybe 25-28 in-Hq but to get down to the 29.xx that you really need to boil out every bit of moisture will require a semi decent pump.
I have used a Robinair 6 CFM/2 stage to do so, but it's also a $600+ pump.
You should really do a triple-pump as well. Pull vacuum, fill with N2, pull vacuum, fill with N2 and then pull a final vacuum and begin your charging process. That should help ensure you've rid the system of moisture.
You need a pretty good vacuum pump to draw down to 500 micron or less. That's virtually almost a perfect vacuum. Most of the cheapo vacuum pumps can do maybe 25-28 in-Hq but to get down to the 29.xx that you really need to boil out every bit of moisture will require a semi decent pump.
I have used a Robinair 6 CFM/2 stage to do so, but it's also a $600+ pump.
You should really do a triple-pump as well. Pull vacuum, fill with N2, pull vacuum, fill with N2 and then pull a final vacuum and begin your charging process. That should help ensure you've rid the system of moisture.
I have HF pump and it pulls 31 mm mercury in about 10 seconds on sealed system.
That pump, just like any other, will last as much, as its maintenance. You have to change oil regularly and lubricate fins inside.
But you getting nowhere without AC gauge kit. This is actual Alpha in Alpha and Omega of AC servicing. Same HF store. Got both.
Why it's 30 mmHg? Cuz any ac repair manual I read so far says to pull 30 mm Hg for 10 (or more) minutes, shut it down, and let it sit. Then check on vacuum in 10 (or more) minutes if it holds. Must be some car ac thing. 30.
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if he were opening up an a/c shop and going to be doing it everyday, then i would never have recommended the HF pump. but since he is just going to do his a/c system, and perhaps that of his friends and family, he might use the pump 5 or 6 times per year at best, and even that will taper off, so the HF pump will last quite a long time, as long as he properly maintains the pump, and perhaps even if he doesnt.
