Purging main drain with air compressor...will this work?

[electricd7]

Hello-

I have a 16x32 inground pool with an 8' deep end. I have a side skimmer and a dual-main drain setup that Ys into a single pipe under ground. Both the skimmer and the main drain come back into separate valves and then combine into a single 1.5" pipe which feeds the pump. I typically try to push water out of my main drain with a shop vac each year, but never have I seen bubbles come out. I usually just pray its OK (and it has been for 5 years.) We live in Indiana, so I would really like to find a better way to create a good airlock with very little water in the pipe this year. What I would like to do is the following:

- Install an air valve into the drain plug hole on the pump
- Plug the pumps exit hole to the filtration system with an expanding rubber plug
- Close the skimmer valve
- Open the main drain valve
- Pump air into the valve in bottom of pump who's only place to go now is the main drain line

Will this work, and if so what PSI should I run the compressor at to be sure there is enough umpf to purge the line of water? My compressor will do 5.4CFM at 90PSI, but something tells me 90PSI is a bit much for the pool lines Has anyone done this and can tell me what I should set the compressor at? Thanks!

ED7

 

[Catanzaro]

I am assuming you are claiming that your main drain is tied into the skimmer, and there could be a diverter valve. Unless you are working with a Cyclone and some adapters, there may not be enough air volume to move the water along. However, if this was my set up, I would work with blow-thru plugs inside the pump housing (this all depends on what type of pump) because some pump baskets on the return size do not really fit properly. If so, work with an NPT fitting. Then another plug in the skimmer port (blow-thru) plugs.

Now ready for this, use dual air compressors. One at the pump NPT fitting or blow-thru plug, and one at the skimmer blow-thru plug. This will do the trick. A total of 15-20 PSI on both ends should work. Blow-Thru plugs unfortunately are not really found locally, and will probably need to be ordered on line.

Once you start seeing bubbles in the main drain, allow the compressors to run for about 60 seconds, "air lock" and call it a day. You do not need to have the same bubbling effect as the Cyclone. Please read the sticky in the closing section as here are a lot of good ideas there.

 

[JLayer01]

I live in Brazil and have a cyclone. If you want to give that a try, by all means shoot me a message and I'll be gladly to let you use it.