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Thread: Advice regarding blowing out lines

  1. Back To Top    #1

    Join Date
    Sep 2014
    Location
    Herndon, VA
    Posts
    4

    Advice regarding blowing out lines

    Background:
    17,000 gallons, chlorine, Virginia, 2 return lines (via cartridge filter), 1 pool cleaner return line, 1 skimmer, 1 main drain. I am planning or replacing filter, pump, plumbing in pool shed, and adding a heat pump for next season. Reasons: filter cartridges are old & want to go SAN, pump is causing suction side air leak and plumbing has some leaks, and pool only gets 80+ on very sunny and hot VA days.
    I have closed my pool three times by myself but now I am starting to question how I am doing it and how I did it this month. I made an error during blowing out the lines this time and I want to see if it is an issue and how to address if it is.

    My written instructions for how I blow out my lines based on observing a professional:
    • Blow out pool cleaner return on near side of pool
    o Front lever pointed left (toward skimmer)
    o Back lever pointed right (toward pool cleaner)
    • Blow out two returns on far side of pool
    o Front lever pointed left (toward skimmer)
    o Back lever pointed left (toward returns)
    • Blow out main drain
    o Back lever pointed down? Toward pool cleaner? Does it matter? (see last question in question section)
    o Front lever toward main drain

    Dilemma:
    Prior to blowing out the lines, I drained the water from the pump and filter to lessen the amount of water I have to blow out. But then I forget to put the plugs back in the pump and filter. I did not realize it until I put antifreeze down the skimmer. I did see water come out of the lines when I blew them out but it is difficult to judge compared to years past because I have never drained the filter and pump before (i.e., it seemed like less water than in the past but that is probably largely due to the draining I did).

    Questions:
    Do you think it is possible or likely that there is water sitting in my return lines because air probably escaped through the filter and pump plug opening while I was blowing out the lines?
    If you think there is water in the lines, is it not a big deal anyway because I put antifreeze down the skimmer (but I don’t see how that would get to the return lines) or it is just an extra precaution?
    If you think I should blow out the lines again, what should I do about the antifreeze? Suck it up with some sort of wet vac? Just blow it in the pool because it is harmless?
    It is my understanding that you plug the return lines after you blow them out. But how does that work when you are blowing out the main drain? Wouldn’t air get trapped? I got nervous about this and unplugged pool cleaner line and pointed the lever toward it when blowing out main drain. I did not notice a big air bubble coming out of the main drain when blowing it out but I could be mistaken.

    Thanks!

  2. Back To Top    #2

    Join Date
    Sep 2014
    Location
    Herndon, VA
    Posts
    4

    Re: Advice regarding blowing out lines

    Anyone have any input? I would really appreciate it.

  3. Back To Top    #3

    Join Date
    Nov 2013
    Location
    Elkridge, MD
    Posts
    81

    Re: Advice regarding blowing out lines

    So I closed mine this year and had a pool company close it last year. i'm not an expert, and my setup is different from yours because I also have a spa using the same equipment, but we can ignore my spa because during the close, the spa intake valve is 'off' and the return line is pointed to the pool with the spa off.

    Since the idea is to clean out the lines using the 'path of least resistance' idea, you want the system still closed off (plugs are all in the filters/pump). When you hook up the air compressor/vacuum, the air will go to whatever valves you have open/unplugged. So you can plug up all but 1 at a time and blow them, then close them off and do the next one. repeat until they're all done.

    So for my system, I had the pool drain closed, skimmers open. The pool returns are obviously open, and I opened the pool cleaner. Once the majority of the water blew out, I plugged the skimmers and the returns up, leaving only the pool cleaner line open. At this point, all of the air only has 1 way it can leave the system: through the pool cleaner line. Once no more water comes out, I plug it up and turn the valve off so no more water can get in through there. Then I opened up a return plug and let water come out. Plug it up and do the other return. Repeat if necessary to get all water out of the return lines. Leave these plugged and no water should get back into these.

    Then I unplugged a skimmer (water should almost geyser out of these). Then I opened the other skimmer and got the water out. I repeated this a few times until as little water came out as possible and plugged them up. At that point, you can turn the valve on the intakes to close the skimmer and open the bottom drain. The air will then bubble out of the bottom drain. I then shut off the air compressor and put the drain valve to off at the same time so that the air stays in the pipe (think putting a glass into a bucket of water upside down). I opened up the skimmer drain plugs and added antifreeze to these last, then plug them back up and put more antifreeze in the skimmer itself.

    As to your dilemma, it depends on how you blew the lines. Did you use an air compressor connected to the pump drain, did you use a shop vac blowing through one line or another? I used an air compressor connected to the pump, with everything still completely closed off so the full pressure pushed out through the returns/skimmers. First thought is you should probably redo it. If you don't and it isn't clear, the pipes may freeze, costing you money. But if you think they may be fine...you could risk it.

    Now to answer your questions:
    1. Yes, likely there is some water in the lines. How much is hard to say...probably depends on how much air pressure was lost through the filter and pump. I'd need more clarification on what you used to close it. Maybe a picture of your equipment/pipes would help too.
    2. If there is water in the returns, you should probably reblow them. There is no antifreeze in these.
    3. If you blow the lines again, you can leave the skimmer/drain valve off. Air should not go through these. If they do anyways, doesn't matter because the skimmers should be plugged already (with antifreeze in there). If you open these up, antifreeze will blow out of it and be wasted. But it is fairly harmless in terms of the ratio of 1-5 gallons of antifreeze versus 15000 gallons of water, so don't worry if it gets in somehow (or when you open the pool).
    4. So if you blow the lines again, only worry about the returns. Make sure all of the inputs are off and the air can only go through the filter and out the returns. Unplug 1 return, it will blow out the water. Close it and open the other return, and the water will blow out. When this is done, you can shut off the air compressor/shop vac and plug up the return lines again. The only thing that should be in them at this point is air.

    Not sure what you mean by "wouldn't air get trapped". The whole point is to get air trapped in the pipes. Any water in there can freeze and damage things. If you are pushing air through and you see water coming out of any of the lines, then you have a problem. You should only see air coming out of the main drain when you're blowing the drain. If you're blowing any of the returns, cleaner line, or skimmers, you won't have air coming out of the drain. If you have the drain open at the same time, there won't be pressure enough to clean out the other lines.

    Again, you really want to have everything but 1 closed up at a time to clean it out. Once you clean it, plug it, shut it off, prevent water from getting back in, and move to the next. Make sure you don't leave everything plugged too long or you will build up too much air pressure and damage things.

    I hope this helps. Again, I'm no expert, but the idea is fairly simple. In the end, all the lines should be plugged up to prevent water getting in them from the pool or rain. The antifreeze should go into the skimmer lines only, none will make it to the returns. Then you'll want to plug the skimmer and put more in on top in case it rains and fills the skimmer up and tries to freeze.
    33,000 gallon gunite pool and Spa (in ground), SWG
    Sta-Rite System 3 Modular Media Filter (300 Sq. Foot cartridge filter)
    Jandy Lite2 Natural Gas Pool and Spa Heater

    Maryland, USA

  4. Back To Top    #4

    Join Date
    Sep 2014
    Location
    Herndon, VA
    Posts
    4

    Re: Advice regarding blowing out lines

    Thanks for the response! I blow air through the skimmer to blow out the return lines, pool cleaner, and main drain. There is no concept of unplugging/plugging a skimmer as you described except at the very end I put a plug in I guess to prevent rain from sneaking in. I pour antifreeze down the skimmer line. That is why anti-freeze will get into the pool if I blow out the lines again as I normally do. But you triggered a thought to simply blow out through the pump cutting out the path from the skimmer (and main drain, I guess) to the pump. Not sure how that would do anything with the main drain but I know blowing through the pump would reach the return lines and pool cleaner line. I guess I need to be understand my pluming -- especially the maindrain. But you said only worry about the returns which I know I can address.

  5. Back To Top    #5

    Join Date
    Nov 2013
    Location
    Elkridge, MD
    Posts
    81

    Re: Advice regarding blowing out lines

    I have expandable plugs I use to close up my skimmer to prevent rain water from getting in. You can also use a 'gizmo' or some other sort of device to close it off. If you blow air from the pump, you can either hook it up (theoretically, thinking about my equipment) to the incoming lines (towards the skimmer/drain), or on the outgoing line (through the filter/heater, to the return lines). So you could blow the returns without pushing any air to the skimmer/drain.

    If antifreeze gets in the pool from any source, not a big deal because when you open the pool it will get in anyways. But again, very small amounts compared to the size of the pool that it will dissipate.

    It was also my understanding that you had the drain open at one point and had big air bubbles coming out of it. while it was doing that, you then turned the drain valve to 'off' (last step in your list, though the directionality you used doesn't help me much because i don't know what it looks like) and air will be trapped in there, which is good. As long as you did this, you don't have to worry about the main drain again. If you opened up the cleaner line and bubbles stopped coming out of the main drain, it's possible some water got back in, and you may want to do it again.
    33,000 gallon gunite pool and Spa (in ground), SWG
    Sta-Rite System 3 Modular Media Filter (300 Sq. Foot cartridge filter)
    Jandy Lite2 Natural Gas Pool and Spa Heater

    Maryland, USA

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