I have a drain at the bottom of the stairs outside my cellar that backs up in heavy rains. I wanted to install a Flood-Guard or some check valve, but the caste iron pipe opening is 2.5" and Flood-Guard valves only come in 2, 3 and 4" sizes. Also, the surface is only 2" below the cellar floor and so a sump pump installation would seem to be difficult.

Then I saw one person on another question seems to have found a way to reduce his pipe, also with an inside diameter of 2.5" by using some sort of insert. I can't figure out what he bought. If anyone has any suggestions, I'd appreciate it.

Here is his solution:
'
For everyones information, I purchased a hard plastic backflow preventer and some rubber parts to try to fashion a fit. As it turns out, the backflow preventer with a 1 1/4" threaded top end and a 1 1/2 " bottom end had a 2 1/2" center which housed the flapper. It fit the hole so tight I had to gingerly force it in with a rubber hammer after I cut the top threaded portion off. I filled the very small crack around the fit with hot melt glue and I am done. It fit so tight I do not feel any back water pressure from underneath could ever force it back out. Now I have a few extra rubber parts to take back and the entire thing costs $2.95. I thank everyone for their responses, which gave me confidence to try something anyway before I tore out the old cast iron drain. Thanks! Dave

Thanks.

Hi Walter...

The fix that Dave used won't work here... different bird all together... ;)

In terms of your issue, I'm just wanting to be sure that the floor drain actually backs up during a heavy rain or is that the drain line (or drywell) is clogged and the rain water isn't draining properly..?

Any chance you can post a picture of the drain itself... would help to advise best!

Finally, if you can't find a way to reduce the threads to 2" and install the flood guard you could just install a CHERNE TEST BALL... see image. It will work to stop the backing up but also won't let anything drain at the same time. Here, insert the test ball, inflate it and leave it if necessary. Cherne test balls are available at all plumbing supply stores.

Let me know more here...

MARK

I saw one person on another question seems to have found a way to reduce his pipe, also with an inside diameter of 2.5" by using some sort of insert. I can't figure out what he bought. If anyone has any suggestions, I'd appreciate it.
I don't remember that but why couldn't you jam a 2 1/2 X 2" PVC reducing bushing, (see image) in the floor drain and install a 2" flood Guard, (see image) in the bushing? Just a thought. Tom