Vacuum Pump question.

[wdrzal]

I would giggle too, I would buy that man a few beers lol

don't giggle yet, I hooked 2 compressors togeater and was not able to get a micron reading ,my meter starts at 2000. That alone does not prove 2 comprseeors won't work.

But more testing needs done.One could hook them to the low side of a system while conecting the bottle to the high side,then doing the same experiment. first to see if you can get it to boil.Then by trying to remove just a few drops of water fro the bottle on the other side of system.

lines losses &restrictions are critical in deep vacuum,just havig a condensor and evap in the loop may prove to much to overcome.but maybee not we'll see.

[matttheniceguy]

What are the chances of someone testing a pair of compressors on a system with a micron guage?

Before wdrzal tried it I would have said low. People who have a micron gauge don't use compressors to vacume a system, and people who use a compressor as a vacume don't own a micron gauge.

Then by trying to remove just a few drops of water fro the bottle on the other side of system.

I'm not too keen on the idea of putting a glass bottle on the high side of the pump, but I was thinking of putting volume marks on the bottle and measuring the rate of evaporation.

As far as figuring out how much of a vacume my pump can pull, I was thinking of trying to boil water at lower temperatures. At 20 degrees the pressure needs to be lowered to 2.339 kPa, which my pump was able to do. At 0.01 degrees the pressure must go down to 0.6113 kPa, or about 4600 microns. If my junkyard compressors can do that, I will be thoroughly impressed.

Here's a question though, why do you need to pull such a deep vacume? I understand the need to evaporate the water from a system and remove most of the gases, but why do you need to pull the vacume so deep? At what pressure/temperature would the compressor oil start to evaporate?

[expansionvalve]

What do you define as low vac?
100micron is a normal figure in my field.
Pulling this sort of vac level gives me peace of mind that all moisture/air in the system has pretty much gone thus reducing the chance that the equipment will breakdown/wear out prematurely, it also helps me sleep at night because if it does breakdown at 3am guess who has to be there by 4am to fix it??
Also, by pulling a deep vac or trying to a micron guage will tell you a little more about the condition of the system, it will indicate the tinyest of leaks and also give you a tiny hint into moisture levels. There have been so many times I have leak tested a system to 300psi and it's held the charge overnight only to find I can't pull a vac due to tiny, tiny leak the next day.
A few effects of moisture and air in systems...
blocked expansion devices or a partial blockage reducing perfromance and wasting electricity, copper plating that ruins compressors, the breakdown of compressor oils... all very important.
I reall am going to sit on my boat here, basically, if you cant pull and maintain a low vac the systems only half good.