Expansion Plug in Main Drain

[dpcory]

Can I leave an expansion plug in my main drain over the winter? I'm in Indiana. I suspected a leak in my main drain line this year and decided to blow out the line, then swim down and put an expansion plug in to prevent leakage. I don't think I could airlock the line anyway with the leak in it, but a I risking more problems if I leave the expansion plug in it?

 

[Catanzaro]

Assuming you have a drain cover. If so, you will have to remove the cover (under water) and then you can plug the drain, wait and see if the water level drops. If so, then you know that it is in the line of the main drain. If you found your leak, then you can leave the plug in the plumbing, and put the cover back on for safety reasons.

My question is how do you know it is the main drain? Have you allowed water to go below all the returns, and if so, has the leak continued? Did you fill up weekly, and if so how much and how long for the leak?

- - - Updated - - -

If the leak is in the line, then creating an "air lock" will not work as you will lose the air inside the piping (assuming you have a crack). You are not risking anything by leaving a plug in if you have a leak. Is it possible that the leak is around the gasket or maybe even the main drain housing has a defect or flaw? Thanks.

 

[dpcory]

Thanks. I'm still not 100% sure the main drain is leaking - hoping to get to the bottom of that next season. See this thread for the details regarding how I ended up with the expandable plug in the main drain:
Main Drain Line Leak

I just wanted to be sure if I leave the plug in, there's not some potential for damage that I'm not considering. It sounds like there's not.