I am installing a new toilet and found that the existing closet flange was broken. I don't recall how the closet flange was installed and I'm not sure how to put in the new one.

I have a 3" metal sewer pipe. The rim of the sewer pipe measures 5" and the actual opening measures 3".

My plumbing supply store sold me a 4" brass closet flange and this doesn't make sense to me. It doesn't seem to be the right fit but I've never done this so I'm hoping someone can help me.

Is the flange supposed to fit inside of the sewer pipe or on top of it, or under it?

Also, should the flange be at exactly the same level as the tile floor, slightly below, or slightly above?

Thank you!!

Nope. Doesn't seem right.

Look at this link: Toilet Flanges from the most FAMOUS Internet PLUMBING SUPPLY (http://www.plumbingsupply.com/toiletflanges.html#instantlyset)

Thanks for the link. It looks like the only appropriate flange from that page would be the 3" cast iron torque set flange. This leaves me with three questions:

1) Is it correct to assume that a toilet flange needs to be installed to fit inside of the sewer pipe?

2) If it's meant to fit inside of the 3" pipe, do I need to make sure that the diameter of the flange is greater than 5" (since the lip on the pipe is 5") so that there is a way to bolt the flange to the subfloor?

3) Will the 3" flange that fits inside of the 3" pipe narrow the pipe opening?

I think you want something like this:

Twist-N-Set® Cast Iron Replacement Closet Flange :: Oatey.com (http://www.oatey.com/Plumber/Shared/ProductGroupDetail/363/Twist-N-Set%c2%ae+Cast+Iron+Replacement+Closet+Flange.html )

It's for repairing a broken CI closet flange.

1. For this application, I think it has to.
2. The OD has to be the same for all flanges. The old one worked, right?
3. Goes without saying.

There are repair kits to fix the ring of the old flange, if that's all that's broken.