A lot of posts say to use a compressor to blow out the lines/main drain etc. What is the minimum size....or the just-right size compressor one would need to close the pool. Seems like it might cost much less than the mighty vac. And, since I need a compressor to attach to the schrader valves to blow out my Paramount in floor system, a compressor is definitely the way to go for me. Also, for those that attach the compressor hose to the drain port on your pool pump, what is the size of that port? Is it an industry standard, or is each manufacturer different? I have a Jandy Max pool pump.

Could you please post a model #, or specs as far as gallons, CFM etc?
Thank you very much!!!

I use a Craftsman 6. Gallon pancake, 1 HP. It pressurizes to 150 psi. I set the regulator to 8 psi. The motor is big enough to keep around 15-20 psi in the tank so I can keep a constant 8-10 psi going into the lines. I connect it to the pump drain port with a 1/4" nipple screwed into the plug port with the other end screwed into a quick connect attched to the compressor hose.

That sounds like the same size as my Porter Cable 6 gallon that came with my nail gun etc. That'll do the main drain as well?

The main drain only needs about 4 psi to clear.

So what are people talking about when they say their pancake compressor, or smaller compressor took upwards of 4 hours to clear all of the lines? I saw in one video on youtube, a guy using a small portable Husky model to do the pool...as seen here: http://www.youtube.com/watch?v=al0HukSJ ... re=related Their are people on here purchasing $300 Dewalt's etc. I would be thrilled to do it with my Porter Cable 6 gal 150PSI dialed down to 10PSI!!

I use a very small sears compressor with no tank and it only takes a few minutes. Anyone claiming to take 4 hours is probably referring to all of the work involved in closing, not just clearing the pipes.

The main drain 8 feet down requires a pressure of over 3.46 psi to clear. Plumbing does not hold that much volume. For example, 100 feet of 2 inch PVC is only 2 cubic feet of volume. A compressor that can put out 4 psi and 2 cubic feet per minute will clear the line in 1 minute.

My compressor is rated at 1.0 CFM at 30 psi. Since it never gets to 30 psi, the volume is going to be somewhat higher, but probably not more than a few Cubic Feet per Minute. It is about 0.5 Horsepower (120 volts at 3.3 amps).

Is this your Sears compressor?:
http://www.sears.com/shc/s/p_10153_1260 ... stAvl=true

I use a 4 gallon, 1.3hp, 3.7scfm dual tank compressor. When I closed last year I think it was only putting out 5psi when I blew all the lines including the main drain.

What make/model. I want to buy something that people are using successfully.
Thanks for all of your help!!!

It is the same thing as the Black and Decker 9527 Air Station (It's probably made by B&D). I don't think that it is made anymore. It really does not take much; your Porter Cable will work just fine. As long as the compressor can exceed 5 psi and 1 CFM, it is going to work.

Note: You will get a little bit of a pressure spike right when you turn on the compressor because the line is full of water and it takes a second for the water to get moving. You will notice the same thing when you start your pool pump, the filter pressure will spike up for a second before settling down.

...and I'm assuming since I'm running it around 10PSI...the pancake compressor won't have to be constantly running out of air and refilling itself. I wonder if that is the problem that others have with a smaller compressor. That they are running it around 40PSI and constantly playing catch-up with the compressor.

If anyone is taking more than a few minutes to clear the plumbing, then they are doing something wrong. 40 psi is unnecessary and a bad idea. You want to avoid over pressurizing the lines. 5 to 10 psi is more than enough.

Sounds good.
Just to play devils advocate. Buying the "Mighty Vac" is totally unecessary unless you are installing vinyl liners. Right?

You do not need the "Mighty Vac" to winterize your pool. Pretty much any compressor will do the job of blowing out pool plumbing. If you have a compressor, then it should work just fine, and there is no need for you to buy anything else.

Note: I drain the system and clear the suction side separately from the returns. I don't try to clear the system with water in the filter and other equipment. If I do clear the entire system, I will drain all of the equipment first.

Some people pressurize the entire system without draining anything first. If the person is clearing the entire system, then it will take a little more than a few minutes. Example

2 skimmers at 100 feet of 2 inch PVC..............4 cubic feet
1 main drain at 100 feet of 2 inch PVC.............2 cubic feet
1 Polaris line at 100 feet of 2 inch PVC............2 cubic feet
1 vacuum line at 100 feet of 2 inch PVC..........2 cubic feet
2 Return lines at 100 feet of 2 inch PVC..........4 cubic feet
3 foot diameter sand filter...........................14 cubic feet.
Miscellaneous.............................................2 cubic feet.
________________________________________________

Total......................................................30 cubic feet

If someone was using a 1 CFM compressor to clear the entire system without draining anything first, then it could take up to 30 minutes. Therefore, that should be about the slowest that it would take to clear a system. And, that does not include the fact that water is going to drain out anyway, which will speed thing sup.

For most pools, the lines will not be that long and if you don't include the filter or other equipment, then it should not take more than 10 minutes in most cases, even with a 1 CFM compressor, which is about as slow as compressors get. Most compressors will do at least 2 CFM at low pressure.

Great advice. Thank you.