Winterizing the Pool Drain Lines

[Neto]

I have a curious question on how to winterize pool drain lines.... So I know you have to put air pressure to the system to drain water out, it seems easy on the return lines and skimmer lines since these will be below water level.... But what about drain lines? once you get the majority of the water out, you basically cant fully take the water out because once you turn off your compressor, water will rush back in because of fluid mechanics... I draw a little picture to explain what I am asking...

 

[Lskul60]

if you are limber and dexterous, you can quickly remove the compressor and insert a rubber plug - creating an airlock in the plumbing.

or, you can pour anti-freeze into the line, allowing it to mix with pool water in the line - lowering the freezing temperature.

 

[Newdude]

If you have a valve / diverter valve, close it while blowing air in and it seals itself. It does blow the water below pool level, but at some point it takes too much psi to be able to blow air out the drain.

 

[Catanzaro]

The best way to do this is to trap air in the line and either close the valve, put a plug in the line, or basket housing, or purchase blow-thru plugs which work great with an air compressor. This past year, I closed the valve like usual, put a plug and upon opening air released and water came siphoning back to the pump.

Can you upload pictures and do you have a shut off valve?

 

[Neto]

I can create air locks with my drains and valves, I will probably remove the handle after the air lock to prevent accidental move of the valve... This is how my equipment looks

 

[avspin]

I create an air lock in one of two ways. First way is insert my blower into the skimmer at the the pool and adjust the valves to the main drain. Once bubbles come up from the drain I close the valve. But my blower is getting old so it no longer has the power to do this. So the way I do it now is I screw in an air fitting into the pump drain hole and use compressed air to get the bubbles to come out the drain then close the valve. Warning, I use an inline valve to lower the pressure to below 10 psi. I don't want to blow out the PVC. Air is now locked in the drain pipe. Seventeen years and never a problem.

 

[Catanzaro]

Neto:

It appears you have a lot going on in the suction side. You can use a black tie strap to remind you and others not to touch the shut off valve. Depending on your system, you may have to perform this function more than once. A friend of mine has a spillover spa and we had to create an "air lock' with the spa as well.