Compressor vs shop vac to blow lines?

Jul 20, 2013
299
Northeast
I found a few articles in regards to this, but I'm still confused on what to get.

I tried 6.5hp shop vac and it'd do skimmers just fine, but for whatever reason it would not do returns or even vacuum line. I can't figure out why, as vacuum line works just fine when used, and it doesn't go through filter\heater. Main drain - forget it.

I know yellow and orange Mighty Vac do the job, but spending over $300 for something I'd use only once a year seems like an overkill.

As for compressors, can someone recommend the specs on what's needed?
Someone (I believe on this site) mentioned that 2 scfm is not good enough. And then pancake ones are not good enough. Then 2HP may not be enough. I don't know anything about air compressors, so need help:)

What is good enough and safe to use? how much psi is too much and can damage lines?

hp
psi
cfm
gallons

Thanks.

P.S. Would something like this be enough to blow all lines?
http://www.sears.com/craftsman-3-gallon ... 915310000P

Or do I need something like this (my neighbor will have this one on upcoming garage sale for about $150. just found out :))?
http://www.craftsman.com/craftsman-33-g ... 916472000P
 
I use a leaf blower, just duct tape the plastic chute over the pipes. I just lower the pool level to below the returns, i have tile that will freeze so I have to (gunite pool). Personally I'd be wary about putting too much pressure on any line. With the water level lowered, "blowing things out" is much, much easier. With a vinyl cover, I'm not sure how much you can safely lower it, however.
 
how about main drain? do you drain it at all or don't bother because you water is low enough? Also, do you have mesh or solid cover?

Also, do you know if you leaf blower would blow returns when water is not lowered at all? the reason I ask is because I tried with shop vac but got no air coming from returns nor vac line. I assume that could be because water wasn't lowered, I just wanted to try the vac, but I also never had water lowered below returns. I was told with solid $3k cover you don't want water to be too low.
 
The cheapest compressor will easily blow out lines. The volume flow rate really does not matter. It will take a few minutes, but it will work just fine. Blowing out an 8 foot deep Main Drain line only takes about 3.5 psi.

ShopVacs are not made for pressure, but for volume.
 
Thanks guys. I ended up with 33gal compressor (got it cheap) and it seems like it did the job. The only thing I noticed - I have two main drains, but only the first one was bubbling. When pool guys used cyclone blower, both were bubbling. I guess it is ok, since both are connected to the same pipe.

I was blowing at about 5psi and it got most of the water out of the skimmers, but not all. As I was blowing skimmers I plugged the skimmer pipe with rubber plug for a few seconds and then I had about a quart of water shooting out.

Question -
1. is it ok to do it the way I did it - by plugging the skimmer for a few seconds? I had someone check the PSI gauge on the compressor it it merely moved, but it appeared the water was just a little brown or rusty and I hope it just picked up some dirt from the pipe.
2. Do I even need to worry about the water left in the pipe, which may not be that much and Antifreeze is cheap in walmart ($3 for a gal of -50)
3. Do you blow heater with returns open or plugged? And also do you leave heater plugs in or out for the winter? Same pool guys left them out first time and then in the 2nd time, saying they got new instructions..

Thanks
 
JamesW said:
The cheapest compressor will easily blow out lines. The volume flow rate really does not matter. It will take a few minutes, but it will work just fine. Blowing out an 8 foot deep Main Drain line only takes about 3.5 psi.

ShopVacs are not made for pressure, but for volume.


I can agree with the OP. I couldn't get my mains to bubble even with a backpack leaf blower duct taped to the line. When I removed the blower, I got a huge whoosh of air back, so I know I was building pressure. The return jets went fine, but I couldn't get the spa returns to go either. Odd. Going to try an air compressor next weekend.
 

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I tried my stihl leaf blower- nothing. My air compressor hooked to the pump drain fitting, regulated down to 25psi blew out the skimmer and returns (after I reversed my pre-pump check valve), but I still had water in my SWG (clear window on the pool pilot bypass valve). I showed it to the pool guys when they were installing my cover. He said that wasn't any good and pulled out their cyclone blower and holy cow- a lot more water came out. Cost me $150 for them to do that. I'm going to buy a real pool blower next year when I close it again.
 
The issue is that leaf blowers and shop vacs have lots of volume but don't have enough pressure to clear the lines and air compressors have plenty of pressure but not nearly enough volume to blow out the lines. If you didn't want to invest in a proper blower you coud make an air receiver out of 4" schedule 40 PVC pipe and cap one end and put a 4" to 1½" reducer and valve on the other that would hook to the plumbing. You could charge it with an air compressor to about 50 psi and use it to blow the lines.
 
Bama Rambler said:
The issue is that leaf blowers and shop vacs have lots of volume but don't have enough pressure to clear the lines and air compressors have plenty of pressure but not nearly enough volume to blow out the lines. If you didn't want to invest in a proper blower you coud make an air receiver out of 4" schedule 40 PVC pipe and cap one end and put a 4" to 1½" reducer and valve on the other that would hook to the plumbing. You could charge it with an air compressor to about 50 psi and use it to blow the lines.

That's a great Idea, now you got me thinking. But on the other hand if you look at why pipes burst then it may not be necessary to get every drop out. Pipes burst because there full of liquid with no air space, so when they freeze and expand something has to give, like the pipe.

But if you blow out the lines to where your skimmer/and returns are bubbling then plug them, you know you have an air space in that line. Same with the main drain, when she bubbles plug it.

No need to get every drop out.
 
A compressor will push out all water to where the pipes go from vertical to horizontal. This is below the freeze level on most pools. As long as the place where the bubbles come out is below the freeze line, there should be no risk of freezing.

If there is water trapped in the system, such as in a "U" or check valve, the water can be removed from that area quite easily in most cases.
 
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