What is the best way to plug inlet/ outlet lines for winter?

My O-ring plastic plugs doesn't fit that tight. I can see tiny bubbles at outlet port when blowing the other one. Do you think Teflon tape might help?

Yes, Teflon tape should help. Try not to over-tighten though, I had one that turned the eyeball fitting and wrinkled the liner, had to replace intire fitting.
 
The threaded kind do not work well with in ground pools. I would suggest the black plugs with the wing nut. Many members have experienced air leaks (small bubbles) over time. I do not know if Teflon tape would be the answer. I tried them and had to take them all out. If they are over tightened, this cause could damage. The black plugs have a nice tight seals and are very easy to remove.
 
Will the rubber plugs work if the inside of the pipe is threaded??

Yes, they work great. You will see bubbles coming out until you tighten them up real well (then the bubbles will stop). This is when you know that the seal is pretty much 100%. Each year, I inspect the return jets underwater and never have I seen damage from the plugs.
 
Kywildcats:

One last item. When you open the pool, because the black plugs are on tight, it may be best to use large pliers. I carefully go down with goggles (you have to lay down on the patio) and apply a little pressure (counterclockwise 1/2 turn), and you should then be fine. You will understand once you turn as the "feel" is there. This is helpful so you do not snap the plastic. My steps (plugs) are inserted a bit inside. Each year, I have to use the pliers to pull out slowly. Next year, I will order larger black plugs.

When the tight seal is broken and the air comes out, it is very easy to pull the rubber plug out. The threaded ones, in my opinion are dangerous if they are over tightened. Although, some people have success with them. I did not.
 
For what it's worth, I've had one bad experience with using those rubber plugs on my returns. After one particularly harsh Winter, I opened in the Spring only to find one of the plugs lying under water on the pool floor. It seems that ice expansion can yank them out due to their conical geometry. Since then, I've only used threaded plastic caps with rubber O-rings to cap the returns. I spread a thin coating of silicon grease on the threads so I won't need a wrench to get them off when I open.
 

Enjoying this content?

Support TFP with a donation.

Give Support
All good info, thank you! I don't think I have to worry about ice getting that deep to grab the rubber inserts. I have three returns, and the pool company put it in 3 different kind of plugs. One Rubber, one screw in with O-ring, and one screw in without O-ring (it had A LOT of plumbers tape on it). I opened the pool this year, and I really never gave it much thought until I pulled them out of storage today. I am going to get three of the same kind tomorrow.

Do you use more force than finger type on the rubber ones?
 
Tomolena:

Information is always good to have. Personally, I do not lower my water more than 1" below the skimmer (only reason is to blow out the skimmers properly). One of the reasons is because of ice expansion. One year, I found that the ice for some strange reason was about 1" away from the liner. Somehow, the heat from behind the steal walls keeps everything in check. The solid cover I have (already in 2 weeks of closing the pool) is 6" above the closing level. By the time it becomes real cold and we have a deep freeze, probability is that another 6" of water will be sitting on the cover. The top layer of water only freezes at most about 1" (At least from the past 3 years of experience). I do not even believe the layer underneath the cover freezes at all, at least in NJ. The time it was frozen was because I kept pumping water off the cover, which now I do not until the spring.

You make a valid point, and I do not feel comfortable lowering the water below the returns for this reason, including the integrity of the liner, pool walls, etc. (Even though the structure and how it was built is excellent). Personally, I see no reason to lower the water that much.

I am assuming that no damage was done on the return line where the plug fell out.

Do you use more force than finger type on the rubber ones?

Best way to describe is that you keep on turning the wing nut until there are no more bubbles. Also, you have to place the plug flush with the threads or they will leak air.
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.