Trouble blowing out main drain

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
Greetings. New homeowner here but not "so" new to the pool scene. Always had above ground pools growing up but with my new home purchase, I have a 18x36 in-ground finally. Nevertheless, I went through the procedure today to close the pool (after reading online) but I wasn't able to blow out the main drain and I'm not sure why. After lowering the water below the skimmers and returns, I removed the chlorinator and the pump.

First, I used the shop-vac to blow out the water from the returns using the return inlet where the pump is located. Water started coming out return #2 (see the picture) but nothing out of return #1. I stuck the shop-vac into return #1 and water/mist started coming out of return #2. After the water/mist stopped spraying, I went back the return inlet by the pump, stuck the shop-vac in there again and only air was coming out of return #1 and #2. I figured the return lines where clear at this point so I capped off both returns with plugs. For safe measure I poured a little pool antifreeze in the inlet section and used the shop-vac to push the antifreeze all the way through the lines.

Now I put the shop-vac into the skimmers/main drain inlet located by the pump. I put the "off" section of the valve in the center to see where the water/air would come out. Water started squirting out of both skimmers BUT no air bubbles were coming out of the main drain. I rotated the valve and put the "off" section to the main side. A little bit of water and a lot of air was still coming out of the skimmers but nothing out of the main. I put the shop-vac directly into skimmer #1 and more water was started coming out skimmer #2. Swapped sides and only air was coming out at this point. I figured the skimmer lines were clear of water at this point. I put the gizmos into the skimmers, poured a little antifreeze into the skimmer box and down both skimmer lines for safe measure again.

Now I turn the valve and put the "off" section to the skimmer side. Stick the shop-vac into the inlet where the pump is located and nothing is happening. You can here the shop-vac struggling because the air wasn't going anywhere. No air bubbles coming out of the main either.

So whats going on here? The only thing I can think off is that the line for the main drain was full and the shop-vac is not powerful enough? Or did I do something wrong here?

I called my local pool store and they told me not to worry about it because the main is located deep in the ground and wont freeze. Thoughts?

Thanks

Oh yea, what is that little pipe in the ground that I put a question mark?








 

blazer58

Silver Supporter
May 29, 2018
227
Chicago, IL
I am sure the expects will reply, but my thoughts are your shop vac is not strong enough to blow the main.

The ? line....maybe an old side suction line. My pool has one that's also 3/4 pipe.
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
Anthony:

If you are comfortable with how you cleared the returns, that is fine. Personally, I would have only recommended lowering the water 1" below the skimmer at most. This way, as you are clearing the returns, if bubbles appear in the winter plugs, it is quite evident. With the skimmers, you could have actually siphoned some water out of the skimmer ports, and then blew air back towards the pump (main drain valve should have been closed off). Or you could have worked from the pump, as it really does not matter. If you closed off one skimmer and pushed air through the other, and reversed the process, then you should feel comfortable with the process.

Regarding the main drain, the shop vac will probably not have enough air volume to push the water along (I assume the main drain shut off valve was in the open position, where the skimmers were closed), made an attempt without any bubbling or success? You could try to Blow-Thru plugs with an air compressor. I started a thread for this reason. Please see thread below.

In addition, there is (conflicting information), well really a few options on how to approach the main drain issue, in where some pool professionals leave the line open for expansion and freezing, while others are more comfortable clearing the line out and trapping air, the "air lock" method. Personally, I am not comfortable leaving anything open, and clear my line. So, entirely up to you how you want to handle the main drain. It would be great if someone could have clear tubing underground with cameras that would follow any freezing process in this country, but I doubt we will ever see that.

Blow-Thru Valve Winter Pool Plugs
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
Place some Teflon lube on the O-Rings and then place a small clear plastic bag with some rubbers bands over the piping as protection. For me, I created a dummy pump setup with the old pump and housing. Purchased the same unions, had the 2" piping and adapters. The cutting, and gluing took less than 5 minutes. The measuring took a long time as there could be no mistakes. The dummy piping actually fits better than original as the 1/8" of plumbing shifted from the suction side over the years, but still fits like a glove. Now, I swap out my pump for the winter. I do not want the pump buried in snow for months at a time. Let alone the rain that we get.

Dummy Pump.jpg

Hayward Pump (Nice & Warm).jpg
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
If you are comfortable with how you cleared the returns, that is fine. Personally, I would have only recommended lowering the water 1" below the skimmer at most. This way, as you are clearing the returns, if bubbles appear in the winter plugs, it is quite evident.
Good advice. Since this is my first time, I figured it would be easier this way to watch the water in the lines turn to mist then finally to air only.

With the skimmers, you could have actually siphoned some water out of the skimmer ports, and then blew air back towards the pump (main drain valve should have been closed off). Or you could have worked from the pump, as it really does not matter. If you closed off one skimmer and pushed air through the other, and reversed the process, then you should feel comfortable with the process.
I did go back and forth a few times from each skimmer to the pump, the pump to each skimmer just to be extra cautious.

Regarding the main drain, the shop vac will probably not have enough air volume to push the water along (I assume the main drain shut off valve was in the open position, where the skimmers were closed), made an attempt without any bubbling or success? You could try to Blow-Thru plugs with an air compressor. I started a thread for this reason. Please see thread below.
After continued reading last night, it appears the shop vac isn't powerful enough to push water down the 8-9 feet. However, I only left the shop vac running for one minute max to try and push the water through the main drain. Perhaps another minute or 2 would have done the job? Not sure. And yes, the valve was properly closed to allow the main drain only the receive the air pressure.

Guess Ill have to pony up and buy the cyclone since I will be closing my pool myself every year. Is the cyclone still the best tool for the job?

In addition, there is (conflicting information), well really a few options on how to approach the main drain issue, in where some pool professionals leave the line open for expansion and freezing, while others are more comfortable clearing the line out and trapping air, the "air lock" method. Personally, I am not comfortable leaving anything open, and clear my line. So, entirely up to you how you want to handle the main drain. It would be great if someone could have clear tubing underground with cameras that would follow any freezing process in this country, but I doubt we will ever see that.

Blow-Thru Valve Winter Pool Plugs
I would like to try the air lock method. Are there thread pvc caps that you can install on the ports for the returns and skimmer/drain?



Or will a cap not work and you need to use the blow-thru valve?

Im trying to understand the air-lock method. Does it work like this? Your blowing air through the main drain line until you see air bubbles. Turn the valve on the port to close the main drain while continuing to blow air. Now you air-locked? Now cap off the port with a rubber grommet/threaded cover and thats it?

- - - Updated - - -

Place some Teflon lube on the O-Rings and then place a small clear plastic bag with some rubbers bands over the piping as protection.

I put a ziplock bag over each port and wrapped some duct tape around the bag LOL. I drained the pump and the filter and put them in the shed.
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
Or will a cap not work and you need to use the blow-thru valve?
Yes, they will work, but you will need to see what size fits best. They can stick out, but if flush inside the piping, this would be a better fit. Try # 8, # 9 and # 10 plugs before you go out purchasing them. I will see if there is any spare 1.5" plumbing laying around and will tell you what size fits it there. The Schrader valve will act as an air lock. Thanks!


I put a ziplock bag over each port and wrapped some duct tape around the bag LOL. I drained the pump and the filter and put them in the shed.
If you want to be creative, purchase another 2 unions, some piping and caps for the system. You can then close off the system instead of using bags, etc. I actually have a dummy pipe with unions for the backwash hose (which I never use - at least once per year) in where I can close it off. I have heard that if something goes wrong in the MPV, that water will discharge from the backwash port and not the filtration, therefore causing issues. Temporarily I can close this off, cut still in the research process of what the ill effect is.
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
Update:

The # 10 plugs are for 1.5" plumbing and the # 11 plugs are for 2" plumbing. These can be used to clear your main drain. Do not over pressurize the air compressor. Start with 10 PSI and do not go past 20 PSI. Let the system run for a while until you see bubbles coming from the main drain. You do not need pressure, but air (That simple). The Cyclone only produces 3.5 PSI (of pressure at least).
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
So I bought the cyclone and attempted to clear the main drain and air lock it. Turned the valve to close the skimmer inlet leaving the main drain to accept the air from the cyclone. Turned the cyclone on and massive air bubbles were coming from the main drain. After 30 seconds or so while the cyclone was still running, I turned the valve to close off the main drain. I put my ear next to the inlet and I hear a very slight hissing sound.

I opened up the valve and this is what I see. I'm no expert but the seal looks fine to me. It still has a rubbery feel to it and doesn't show any signs of cracking.


I have gizzmos in the 2 skimmers. I figured the only way I could make an air lock for the main drain was to seal off the skimmer inlet with a rubber plug inside the valve, utilize the cyclone to drain the main again, turn the valve to seal off the main drain inlet and finally sticking another rubber plug into the inlet for the valve. Will this work?




I confirmed that if the main drain is not cleared, then water is literally filled in the main drain pipe even with the grass. That for sure will freeze.

I'm still not confident that my air lock method will work this way but I have no way to confirm. I don't hear any hissing but even the slightest release of air will continue to leak over the next few months and likely have no pressure left. What should I do?

When you guys do the air lock method, does your valve completely seal and block all air from escaping?
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
Anthony:

I ran into the same problem as you did this year. Well guess what? My valve looks identical with no indication of wear, etc. My friend who is in the business came over with a new valve. We removed the parts from the new valve and swapped out the parts, leaving the body intact. We then cleared the drain again, and closed the valve (no more hissing). In addition, I contacted Pentair customer support by phone and by e-mail, as these valves are 100% positive seal.

What you have done is fine for now, and it will work, but I would recommend fixing this in the spring. Purchase a new valve, and remove the internal parts (all one piece) and swap it out. It really is an easy fix. I had the same issue with a diaphragm on my sprinkler lines and swapped out the parts as well. The valve would not close, remaining open all the time (almost same concept).

The valves must be air tight, as in the first few years, upon opening, when the main drain valve was opened, I could hear air escaping out of the system. It is very possible that the valve went bad during the last closing and I was never aware. I really believe that the 100% positive seal expectancy of these valves is only a few years, and nothing longer. There is a lot of air trapped in the line, especially with the use of a Cyclone.

Even if the air leaves the valve slowly, the water in the main drain will be level with the pool water. For me, I had originally used a plug in the bump basket and turned the shut off valve on the skimmers towards the main drain as I was going to fix this in the spring. Eventually, I decided to swap out the parts and call it a day. You are fine with what you have done and smart thinking.
 

Pool_Medic

In The Industry
Apr 1, 2018
1,197
Bangor Maine
Attempting to air lock a main drain is silly. Yes it will let air in eventually. Put a bottle in the freezer half full of water, zero damage, the ice expands up and out. Now try it with a cap on it, it’s not pretty. Thousands of pools in freezing climates never are closed this way.
 

Kiss4aFrog

LifeTime Supporter
TFP Guide
May 22, 2013
2,738
Hudson, WI
Guess Ill have to pony up and buy the cyclone since I will be closing my pool myself every year. Is the cyclone still the best tool for the job?
Plenty of people say you can do it with a shop vac, I never tried. I finally broke down a couple years back and bought the Cyclone. I made an adapter that screws into the skimmers and I blow to the pump. Works great and with this year I figure I've paid for the Cyclone in not having the 125-150 bill for the company to come out and close the pool. Blows the main drain easily.

.
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
Clearing the main drain line is necessary. The industry has been winterizing the main drain lines for decades. Whether or not to winterize the main drain has plagued the industry for decades as well in certain parts of the country. In addition, most pool professionals winterize the main drain line by clearing the line and shutting off the valve. If a pool owner is worried about a leaking shut off valve, then clearly he/she can place a plug behind this in the basket as secondary backup, or replace the internal components if there is an issue.


Please read the thread below as there is some pretty important information with facts and science to back up the information:


Can't blow air into main drain line for closing


Please pay particular attention to post # 6 from Jason Lion, and then followed up with post # 7 and post # 8. There is logic behind this method. There is discussion on ice, and that it can form inside a pipe, thaw, and refreeze causing damage. There is also discussion on how ice has trouble expanding in 90's, and turns, etc.


Post # 8 is extremely interesting:

If ice formation can move freely between pipes without any concern, then clearly there would be no reason to use a Gizzmo, close the skimmer piping, add antifreeze, foam rope, or even pool noodles.


"If this theory were true there'd be no need to prevent ice expansion in skimmers, would there? The problem is that water freezes from the top down, potentially sealing it in place and making horizontal expansion more likely"

Another reason to use a compressor that moves the water down to the main drain and trap air is as follows:


Post # 6 from Jason Lion:


"The air will compress as it cools, so some water will get in the bottom of the pipe, but there is normally enough air to keep the water below the frost line".

In the end, a FORUM member should winterize his/her own pool with whatever methods they are comfortable with. There are only options, and there is not a "right" or "wrong" way of doing this. Imagine the amount of money that will be required and spent to correct broken pipe underground? One can not just make a blanket stament on what is the correct and incorrect way of winterizing a pool.
 

Pool_Medic

In The Industry
Apr 1, 2018
1,197
Bangor Maine
Not sure where you are getting your facts but they are skewed. Pool professionals do blow main drains always, rarely are they plugged as you suggest. You are strongky promoting air locking, which is rarely If ever done. I’m in a climate with severe freezing temps and none around here do as you are suggesting. Just because something is said enough times doesn’t make it right. You are the one suggesting air locking the main drain, yet you yourself have said it’s failed. So what’s the point of getting members to buy expensive exoansion plugs if they don’t work? Blowing the main drain will move the water down to level with the pool. Provided that line isn’t locked, the ice will and can grow upward into the line and downward into the water. You are adding an unnecessary thing to a closing. For years this forum talked closings, then you added the air lock and expansion plugs in returns. $0,99 closing plug versus $4-$8 expansion plugs.
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,445
Monmouth County, New Jersey
years this forum talked closings, then you added the air lock and expansion plugs in returns
I did not add the "air lock" and "expansion plugs", as they have been used in the past. The link shown above is from Jason Lion, the original creator of pool math and from 2008. There are many threads on closings way before I entered the picture from seasoned members and industry professionals, so please use the "search function".

I guess they must all be wrong.

Not sure where you are getting your facts but they are skewed
The facts are from the forum members prior to my postings, and from pool professionals here in NJ as well.

Again, I guess they all must be wrong.

You can go back from 2008-2015 in the closing section and read the threads if you wish.
 

blazer58

Silver Supporter
May 29, 2018
227
Chicago, IL
Pool_Medic.....If air locking the main is not needed, then what do yo do when your pipe is in the freeze zone ?
Here it can freeze down to 4 feet or so, half of my pipe is well in that range.
Personally I air locked mine
 

Pool_Medic

In The Industry
Apr 1, 2018
1,197
Bangor Maine
Pipes are never air locked here, you blow the line to move any water in the lateral piping to get it level with the pool water. The pipe is left unplugged and the water in the vertical section can freeze and thaw. The key to any pipe cracking is not allowing the freezing water to have an area to grow to. The video showing all those pipes failed because he never filled any and left them outside uncapped. Had he have done that, he would of seen the ice just growing out of the pipe. Thousands of pools in the northeast are closed this way by professionals. Skimmers are different because one end is plugged. The main drain line is never plugged, air on one side and water on the other=room for expanding ice to grow.
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
Seems to be 2 total opposite side of the coin in regards to opinions here.

Pool Medic, even after blowing out the main drain and having the water return into the line, I confirmed that the water level rose to approximately 12-14 inches below ground level. That certainly is above the frost line in NY. Is it your opinion that leaving the water in that pipe at that level will not be problematic once the freezing temps arrive?

Creating an air-lock to keep the water below the frost line is certainly easy enough provided the valve will seal properly.

Right now in my section of NY, we probably have at least another month before the temps drop below freezing and consistently stay there. So in a few weeks ill head back out to the main drain pipe, remove the plugs and turn the valve to see if there is still a significant amount of air trapped in the pipe. If I hear that large rush of air escaping then I know the air-lock is holding. If not, Ill replace the seal and go from there