Help - Double Smoke Shelf?

[Jengah]

I have a fireplace that was built in 1973 with a heatilator-type unit in it. I'm going to install a Regency I1100 into it with a 6" SS chimney liner. The plan was to cut out the middle convection tube, then part of the steel firebox wall to allow for the chimney liner to go up through it. However, when I look up past the convection tubes I see a blockage (see photo). You can see from looking down the flue that there is about a 4" shelf above the "normal" smoke shelf (see photo and drawing).

1. Can anyone tell me if I need to remove this extra shelf?
2. What is my best course of action here to get my liner from the top of my insert up through this maze? Do I need special ovalized pipe or should I just try to cut things out and get as much of a straight shot as I can to avoid curves?

 

[bholler]

That looks pretty much like a standard heatilator. And wow have you ever cleaned that thing? That is one of the dirtiest fireplaces i have seen in a long time. Make sure you get all of that out of there.

 

[Jengah]

That looks pretty much like a standard heatilator. And wow have you ever cleaned that thing? That is one of the dirtiest fireplaces i have seen in a long time. Make sure you get all of that out of there.

LOL - yeah - it's dirty, the guy I bought the house from used the fireplace to heat the place all the time. He also burned anything that was combustible in there.

Do you have any comments on the double smoke shelf. I can't find any design diagrams anywhere that have the same sort of configuration.

 

[bholler]

Do you have any comments on the double smoke shelf. I can't find any design diagrams anywhere that have the same sort of configuration.

It looks like most i have worked on. My advice is start cutting and dont stop till the liner fits. It is a pain in the ass that is why i hate those things but no way around it