Advice on chimney liner system for insert

[Badastronaut30]

My fireplace flue is about 7x20. I'm going with a lopi freedom that runs 6 inch pipe. My 30 foot tall exterior wall chimney has seen better days. My chimney sweep has suggested 1/2 to 1/4 inch ceramic wool insulation. He said most likely he will have to ovalize the flex pipe with a machine to make it fit. He said that he can ovalize down to 5inch in diameter. Will this be ok with my lopi freedom? any reason to be concerned? Could it mess up my draft? I understand it will be a 6 inch pipe but wont draft as well since it would be oval shaped.

The other company I'm working with wants to run ridged non insulated pipe. Or bust out my flue tiles to insulate. I'm leaning strongly with the chimney sweep install.

 

[bholler]

we would probably break out the tiles and install an insulated heavy flex liner. Ovalizing will work it will compromise performance slightly but at 30 feet it should work and if he is using a ovalizer it will be nice and consistent so cleaning wont be that hard. So basically as long as he uses 1/2" insulation I would be ok with an ovalized 6" it is not perfect but should work well. But breaking out and putting in round would be best.

 

[webby3650]

You will have no issues with that ovalized liner. My freedom did just fine on a 12' liner. I have a very short flue, I never experienced any draft issues. At 30', it'll do great!

 

[begreen]

Is 7x20 the ID or OD? I'm wondering if you could go with a 5.5" insulated liner.

 

[fraxinus]

Once again, I'm going to suggest checking into a poured in place liner. SupaFlu or one of the other brands. You would avoid a lot of problems, not the least of which would be the potential for damage in breaking out the old tile lining.

 

[mellow]

Poured in place seems to be a great thing in some regions and non-existent in others, guess it is worth a check and your insurance company might help foot the bill as well since it is considered a "restore".

I would go the insulated 5.5" route myself.

 

[chimneylinerjames]

A 5.5" liner will work fine. Especially if you use a smooth inner wall liner. Basically the smooth wall will offset any difference from downsizing a 1/2". But definitely use 1/2" insulation.