Main drain no bubbles

[Sickfickleduck]

Hello all I’ve followed the pool closing and chemistry guides but I’m having an issue, last year when I closed my pool I blew air through the lines and the main drain bubbled and I air locked it. This year when I used my compressor( large dewalt) no bubbles came and air came back through the pump through the little nozzle I had attached. Also when trying to close the valve it close 90 percent of the way but is left open slightly as shown in the photo

I also waited a few minutes before air locking so the knob was not immediately closed. I have attached a picture. The second last knob from right is for the main drain. Should I leave it as is or just leave that one open as ive also read conflicting views on whether one should even airlock a main drain.

I am in the Midwest and depending on the year we definitely get well below freezing and it can be blisteringly cold and I have a concrete deck so I’m really no trying to spend thousands to get pipes fixed. Any advice is welcome.

 

[Newdude]

This year when I used my compressor( large dewalt) no bubbles came and air came back through the pump through the little nozzle I had attached.

Any chance the ball valve broke and it locked/seized ? They all seize, it's just a matter if 3 years or 5 years.

I also waited a few minutes before air locking so the knob was not immediately closed.

It will fill as fast as an open straw that you dunk. The 'straw' is 1.5 inches but the 'drink' is 30k gallons, so.

But I bet is frozen anyway because of how it blew out on you. If air was escaping somewhere else you wouldn't have known and would have thought it was working.

Should I leave it as is or just leave that one open as ive also read conflicting views on whether one should even airlock a main drain

All lines need to be blown below the frost line. (Google your areas frost line for the map). The skimmers and returns are easier to empty and they get capped. Because the drains will remain open, you have to air lock that pipe at the pad, while it's under pressure.

 

[Sickfickleduck]

Any chance the ball valve broke and it locked/seized ? They all seize, it's just a matter if 3 years or 5 years.

It will fill as fast as an open straw that you dunk. The 'straw' is 1.5 inches but the 'drink' is 30k gallons, so.

But I bet is frozen anyway because of how it blew out on you. If air was escaping somewhere else you wouldn't have known and would have thought it was working.

All lines need to be blown below the frost line. (Google your areas frost line for the map). The skimmers and returns are easier to empty and they get capped. Because the drains will remain open, you have to air lock that pipe at the pad, while it's under pressure.

When you mean frozen I guess I’m not understanding also idk what to do as I can’t get this repaired until we’ll after the next few weeks and by then it will have been cold enough to freeze at this point is it just pray that the pipes don’t burst?

 

[Newdude]

When you mean frozen I guess I’m not understanding

I'm guessing the valve is broken in the closed position. When you go to blow it the air has nowhere to go and escapes elsewhere.

It's just a guess but it would explain what you're seeing when you tried. Or wherever else the air is leaking from is robbing enough pressure that the compressor then doesn't have the power to do the job.

I can’t get this repaired until we’ll after the next few weeks and by then it will have been cold enough to freeze at this point is it just pray that the pipes don’t burst?

I'd try another way with a larger blower, preferably a cyclone, and if that didn't work, cover the pool to shield it from the fall crud and leave the equipment running until you can get it fixed.

 

[Bperry]

When you mean frozen I guess I’m not understanding also idk what to do as I can’t get this repaired until we’ll after the next few weeks and by then it will have been cold enough to freeze at this point is it just pray that the pipes don’t burst?

It takes several days of extended below freezing weather to freeze pipes so I think you have plenty of time if you can get to it before end of October.