How to Air Lock my main drain

[ctraveler]

Can anyone tell me if it’s possible to air lock my main drain based on my plumbing setup and if so how? The pool company that usually closes our pool always says that they air lock the main but I can’t figure out how they are doing it. It seems that I would need a valve between the skimmer and main drain line to properly air lock the main drain.

 

[Pool_Medic]

Is there a ball valve on either of those suction lines so you can just blow the main? As I see it, no, they didn’t air lock it unless they removed pump, blew from the union and once it bubbled, they added a rubber pressure plug. You should note between the time they pull the blower nozzle out and insert said plug, the water rushes into that void so it’s truly not “locked” at the bottom of the pool.

 

[wireform]

You can use a plug with a Schrader valve, like a tire valve in the pump to air lock the main drain. Blow out and plug the skimmer once that line clears and then the rest goes towards the main drain and stays air locked. The only thing I don't like if this were true is how do you get some anti freeze into the skimmer line.

 

[ctraveler]

You can use a plug with a Schrader valve, like a tire valve in the pump to air lock the main drain. Blow out and plug the skimmer once that line clears and then the rest goes towards the main drain and stays air locked. The only thing I don't like if this were true is how do you get some anti freeze into the skimmer line.

I already blew out the skimmer, and return lines using my 6hp shop vac. I also added antifreeze and put a gizmo in the skimmer. To blow out the skimmer I inserted the shop vac hose into the pump And that blew out fine, I had water shooting out of the skimmer but with the skimmer plugged I wasn’t seeing any bubbles coming out of the main drain which I was assuming that I should but then I realized that even if I saw the bubbles I didn’t know how to air lock it. I’m guessing that my Shop vac doesn’t have enough power to blow out the main drain but the plug with Schrader valve is a very good idea. My existing compressor is a little 2 gallon which I don’t think is powerful enough but I have been thinking about getting a 20 gallon so this might be a good excuse and that should be able to blow out the main drain.

 

[wireform]

I already blew out the skimmer, and return lines using my 6hp shop vac. I also added antifreeze and put a gizmo in the skimmer. To blow out the skimmer I inserted the shop vac hose into the pump And that blew out fine, I had water shooting out of the skimmer but with the skimmer plugged I wasn’t seeing any bubbles coming out of the main drain which I was assuming that I should but then I realized that even if I saw the bubbles I didn’t know how to air lock it. I’m guessing that my Shop vac doesn’t have enough power to blow out the main drain but the plug with Schrader valve is a very good idea. My existing compressor is a little 2 gallon which I don’t think is powerful enough but I have been thinking about getting a 20 gallon so this might be a good excuse and that should be able to blow out the main drain.

Are you sure the main drain is active and not plugged at the bottom. Your pictures of the plubining tell me this isn't a new pool.

 

[ctraveler]

Are you sure the main drain is active and not plugged at the bottom. Your pictures of the plubining tell me this isn't a new pool.

Yes, I don't think it's plugged. I got the plug with Schrader valve and put it in my pump and hooked up my little compressor. I set the compressor to 30psi and I see bubbles coming out of the main drain. I let the compressor run for about 30-45 seconds with the bubbles coming out of the main drain before the compressor runs out of air. I thought I was good but then when I turn off the compressor I hear water running back through the line toward the pump so I don't think the compressor got all of the air out and didn't properly airlock the main drain. I'm going to get a bigger compressor with a larger tank and more powerful motor so I can keep it running at 30 psi longer before it runs out of air. Actually I just had a thought could the fluid I'm hearing coming back through the line actually be coming from the skimmer, maybe some water that was left in the pipe or the antifreeze. Hmm...

 

[wireform]

Yes, I don't think it's plugged. I got the plug with Schrader valve and put it in my pump and hooked up my little compressor. I set the compressor to 30psi and I see bubbles coming out of the main drain. I let the compressor run for about 30-45 seconds with the bubbles coming out of the main drain before the compressor runs out of air. I thought I was good but then when I turn off the compressor I hear water running back through the line toward the pump so I don't think the compressor got all of the air out and didn't properly airlock the main drain. I'm going to get a bigger compressor with a larger tank and more powerful motor so I can keep it running at 30 psi longer before it runs out of air. Actually I just had a thought could the fluid I'm hearing coming back through the line actually be coming from the skimmer, maybe some water that was left in the pipe or the antifreeze. Hmm...

Not sure I'm right but and if the compressor is big enough to blow out the skimmer line from the skimmer side towards the pump then drop some anti freeze in and seal it off with a regular tight plug. Tap it in there real well. Next go to the pump side and blow back. The only place the air can go is to the main drain as it has less resistance. That may work.

 

[Catanzaro]

I would suggest highly to either use the blow-thru plug with an air compressor as it works. The blow-thru plug does not operate like the Cyclone and a shut off valve, but you should be fine. I personally close the shut off valve first and then shut off the blower within a split second. You will hear the air lock.

The other idea is to lower the water below the skimmer and push water out of the skimmer and instead of a Gizzmo, use a black plug and pool noodles for expansion, plus a bottle of antifreeze, etc. Once the skimmer line is completely closed off, then go back and use the blow thru-plug with an air compressor and once the main drain bubbles (under 20 psi) for about a minute or so, then shut down compressor and place cap on the plug.

I have information in my link below:

Blow-thru plug experiment

Blow-Thru Valve Winter Pool Plugs

Concept of closing an IG Swimming Pool

The concept of closing an in ground swimming pool