Heated plumbing stack cap/ring?

[MNSparky]

I got a call from a builder who has a residential customer whose main plumbing stack ices over at the top on the roof when ever temps dip below 0. This causes sewer gas backup obviously. His plumber said there is an electric heated ring that sits on the top to keep it clear. I've never heard of such a thing and a google search came up with nothing. Anyone ever heard of this?

The only thing I've ever used is heat tape for plumbing...

 

[gadfly56]

I got a call from a builder who has a residential customer whose main plumbing stack ices over at the top on the roof when ever temps dip below 0. This causes sewer gas backup obviously. His plumber said there is an electric heated ring that sits on the top to keep it clear. I've never heard of such a thing and a google search came up with nothing. Anyone ever heard of this?

The only thing I've ever used is heat tape for plumbing...

You didn't try very hard. Look here.

 

[MNSparky]

You didn't try very hard. Look here.

I saw that one, but it didn't match the plumbers description. He said it was just a ring that slid over the top of the existing cast iron stack. He had no idea on brand or what it was called.

I think the one you have here required the top portion portion of the stack to be replaced with it.

 

[drcampbell]

Heat tape can be used on drain, waste & vent pipes, same as supply pipes.