SS 5.5" M-Flex Liner??

[gazerbeam06070]

Hi Folks - Never heated with wood and about to take the plunge. Love this forum, its been very helpful.

We have selected the Enviro Venice 1700. Local dealer has proposed installing it using a stainless steel 5.5" M-Flex liner. Chimney is pretty tall - over 30' I'd guess.

I read so much here about using 6" liners. Is a 5.5" something to be concerned with? Or am I obsessing over nothing?

Thanks
Ken

 

[bholler]

Hi Folks - Never heated with wood and about to take the plunge. Love this forum, its been very helpful.

We have selected the Enviro Venice 1700. Local dealer has proposed installing it using a stainless steel 5.5" M-Flex liner. Chimney is pretty tall - over 30' I'd guess.

I read so much here about using 6" liners. Is a 5.5" something to be concerned with? Or am I obsessing over nothing?

Thanks
Ken

You would have to ask the stove manufacturer if running a 5.5 is ok. Are they going to insulate the liner.

 

[gazerbeam06070]

I ask, they said insulation was not necessary.

 

[gazerbeam06070]

Also I checked the Enviro manual. It states to refer to local codes in the USA for installation.

 

[bholler]

I ask, they said insulation was not necessary.

Did they check to see if you have the required clearances to combustibles from the outside of the chimney structure? If not what reason did they give that insulation wasn't needed?

 

[bholler]

Also I checked the Enviro manual. It states to refer to local codes in the USA for installation.

Yes but code doesn't tell you if a 5.5 liner is ok with that stove. You will have to call them.

 

[gazerbeam06070]

Did they check to see if you have the required clearances to combustibles from the outside of the chimney structure? If not what reason did they give that insulation wasn't needed?

Yes but code doesn't tell you if a 5.5 liner is ok with that stove. You will have to call them.

They were working from my photos and measurements, and are coming Monday for a physical inspection. Then we will actually book the order if all is good.

I'll call Enviro wrt the liner size.

Thanks

 

[bholler]

They were working from my photos and measurements, and are coming Monday for a physical inspection. Then we will actually book the order if all is good.

I'll call Enviro wrt the liner size.

Thanks

So they told you insulation was not nessecary without a full inspection? There is no way they could say that without being on site to check for proper clearances. To me that tells me they either don't know the codes or don't care about them.

 

[rdust]

I run my BK on a 5.5 liner, 27’ of liner plus a few feet of double wall off the stove. I also ran a Lopi on it without any issues.(actually too much draft for the Lopi)

My guess is it’ll be fine draft wise, the code stuff I’ll leave to the pros.

 

[HomeinPA]

The liners I've physically measured have worked out to 5.5" ID is 6"OD and 6" ID is 6.325" OD. When they specify 6" they don't specify ID or OD. Just another point of confusion.

 

[gazerbeam06070]

The liners I've physically measured have worked out to 5.5" ID is 6"OD and 6" ID is 6.325" OD. When they specify 6" they don't specify ID or OD. Just another point of confusion.

Thanks I had suspected something along these lines.

 

[bholler]

Thanks I had suspected something along these lines.

Call the manufactuer and ask them. That line of reasoning is just silly.

 

[Ctwoodtick]

A while back, I got curious about how several of the bigger stove stores in my area handle the insulation question. Of the 3 places I called, there was a consensus that insulated liners is either not done or not needed. Unfortunately, these places were incorrect.
Of the sweeps in my area, its seems that most insulate, but definitely not all.
Asking a prospective installer their thoughts on insulation is a great way to determine if you have a reasonably diligent installer or not. If the flub that question up, just move on.

 

[DB Cooper71]

Bottom line on insulation is that most of the time it is necessary. I did a recent installation of a fireplace insert and didn't insulate the liner. After posting here, bholler asked me the same questions about having a code compliant chimney. He also directed me to the pertinent code, UL1777. After about 10 minutes of research and reading from a couple of sources, I found out that he was right. I needed to insulate it, in order to be code compliant and for the safety reasons. I had to take it all apart and do it over, the right way. Please consider insulating your liner. Your homeowners insurance might not cover any fire damage if, God forbid, there was ever a chimney fire. If it's insulated, then its code compliant, and they probably couldn't deny any fire damage claims.

As far as the liner size, with a chimney that tall, I wouldn't think the draft to be a problem by downsizing 1/2" in diameter. You're losing 4.75"sq of area in the cross section, 28.25"sq for the 6" ID vs 23.75"sq for the 5.5" ID. Someone please correct me if I'm wrong.

Why do they suggest the downsize? Do they think it will overdraft? You could install a flue damper if necessary to decrease the draft. I had to go with a 5"x7" ovalized liner due to having a small rectangular flue, 6"x8". The problem with using anything other than 6" is that most flue collars are made for 6" ID, as are the top plates and rain caps. You can get reducers and top plates/rain caps in that size, but they are typically harder to find. Believe me, I have a tough situation with the ovalized liner. Going with 5.5" may still be easier than my situation, but 6" is much easier to find appropriate "snap together" parts.