Maybe bottom block off plates aren't always a good thing ...

[branchburner]

That's what everyone said about installing a block off plate too

Except I think given an external chimney, where it is clear the liner is going to lose heat, the way to prioritize would be:
1) insulate liner
2) add block-off

Given your dilemma, this in hindsight obviously makes even more sense with a basement install with a greater likelihood of downdraft. It's good of you to post your observation, because I think you are correct, this scenario of bad draft performance due to a block-off is not ever mentioned. But bholler is right, by not having a block-off and insulation you are basically paying to heat the great outdoors 24/7 just so your chimney can be warm enough to draft.

When you said that you were running only one fire a day, was that normal or just during that month because you had to preheat the stove? Because if you don't burn full time, and always have some cold-stove time with no coals, that is what allows the total cooling and reversal of draft. I would think even just a few coals hours after a productive fire might provide enough warmth to keep the draft, so if you were burning more hot and more often, if not full time, you might not experienced the same bad block-off effect.

An inexpensive way to insulate your existing liner would be with loose perlite, but be aware that this is likely not an approved insulation method per the liner manufacturer, and thus not code compliant. It sounds like you are not using the stove to heat your entire house, so probably not a big deal, but I suspect that running the stove is not saving you as much on your heating bill as it would be with both insulation and block-off.

 

[bholler]

By the way here are the applicable codes

R1003.18 and R1003.11

in this

(broken link removed to http://codes.iccsafe.org/app/book/content/2015-I-Codes/2015%20IRC%20HTML/Chapter%2010.html)

 

[bholler]

Okay, you are making a great leap there. I see what you did. Because you have never heard of a liner that doesn't require insulation to maintain the UL listing you "assume" that insulation is required for all liners to meet code. The code you reference is just that all UL listing requirements be met. Ah, that's a mistake. There is no code that requires an insulated liner for a fully functional and legal masonry chimney.

There is a parallel thread going on as well where you are the only one making this insulation requirement claim. Perhaps what you really mean to say is that insulation isn't required unless your particular liner brand requires it in that liner's manual.

Have you read ul-1777? Have you seen those tests conducted? Can you tell me what liner you have installed? Can you tell me of any liners that have been tested to ul 1777 without insulation on them for use with wood?

And by the way the link you provided is absolutely wrong because they are talking about installing an olympia liner and if you read this link (broken link removed)

They very clearly say that their liners need insulation in order to maintain their listing.

 

[bholler]

There is a parallel thread going on as well where you are the only one making this insulation requirement claim. Perhaps what you really mean to say is that insulation isn't required unless your particular liner brand requires it in that liner's manual.

Nope that is not what I mean and regardless the person I was talking to had an olympia liner.

And another thing can you absolutely confirm that your chimney meets the required clearances the whole way to the top.

 

[Highbeam]

I guess I will add this as another of the reasons I removed my uninsulated liner, professionally installed of course, and tore down the masonry chimney to replace with class A pipe. I guess all of these licensed professionals lie about everything eh?

 

[branchburner]

Hope a block plate doesn't cause any draft issues. I have a 28ft exterior chimney with an insulated liner

In addition to the block-off plate not letting warm house air into the flue, to keep the liner warm, here are contributing factors to the OP's problem:
1) exterior chimney
2) uninsulated liner
3) not burning 24/7
4) basement install

While 1, 2 and 3 contribute to cold air accumulating in the liner, it is the basement install that possibly most contributed any negative pressure "stack effect" to the reversal of draft.

 

[jscs.moore]

I have been in the industry a long time and have installed hundreds of block off plates and have never heard this complaint before. I am pretty sure you will be fine

Thanks bholler...you da man!

 

[branchburner]

Just for fun, I started a poll about block off plates and whether or not people have any problems with down draft.

Check your questions... I think I see a cut-and-paste error.

(If getting married, be sure not to say "I do not" when you mean to say "I do" ...
...on the other hand.)

 

[bholler]

I guess all of these licensed professionals lie about everything eh?

Not all of them no

 

[jscs.moore]

In addition to the block-off plate not letting warm house air into the flue, to keep the liner warm, here are contributing factors to the OP's problem:
1) exterior chimney
2) uninsulated liner
3) not burning 24/7
4) basement install

While 1, 2 and 3 contribute to cold air accumulating in the liner, it is the basement install that possibly most contributed any negative pressure "stack effect" to the reversal of draft.

Thanks for the feedback branchburner! I'm only going into my second season of burning and I'm really looking forward to more efficient heating from my insert with the block off plate installed. Also, I have truly seasoned wood this year so I'm very hopeful I will be able to heat our house nicely without running the heat pump much!

 

[iluvjazznjava]

Check your questions... I think I see a cut-and-paste error.

(If getting married, be sure not to say "I do not" when you mean to say "I do" ...
...on the other hand.)

Doh! You are right ... unfortunately I cannot edit the existing questions of the poll, I can only add new responses. Maybe a moderator can fix it. My apologies.

 

[iluvjazznjava]

In addition to the block-off plate not letting warm house air into the flue, to keep the liner warm, here are contributing factors to the OP's problem:
1) exterior chimney
2) uninsulated liner
3) not burning 24/7
4) basement install

While 1, 2 and 3 contribute to cold air accumulating in the liner, it is the basement install that possibly most contributed any negative pressure "stack effect" to the reversal of draft.

You are correct in your assessment, I don't have an ideal setup by any means. What was so striking though is the difference between the draft with and without the block off plate. Without it, I have never had an issue and it drafts very well (never had any need to prime the flue). As soon as I put on, it was the exact opposite situation. It's kind of one of those "if it ain't broke ..." type of situations.

Neither my wife or I like having the stove going too much when we are gone during the day at work (we have done it a few times), so we tend to burn once a day during the week (in the evening) and sometimes more often on the weekend. With the one fire a day setup, my burn time would be 6-8 hours in my F55, and it would cool down enough to have draft problems again by the next evening.

I'm willing to learn from others, which is what is so great about a forum like this. I'm still trying to figure out what brand of liner I have - I seem to have lost the paperwork. I'll ask the stove shop that did the install. If its compatible with some sort of insulation system, I may consider giving it a try. I have never heard of perlite and don't know if its readily available in my area.

For now, I will rest easy with the knowledge that my setup, while not as efficient as possible, works well.

 

[bholler]

I have never heard of perlite and don't know if its readily available in my area.

Perlite is not an approved liner insulation and you don't really want to use pour in for an insert there is to much potential for leaks. For an insert you would want to use wrap on the liner.

What was so striking though is the difference between the draft with and without the block off plate.

Do you have a draft problem or do you just have a cold startup problem? Meaning once you get the draft established does it work well?

 

[yooper08]

So, let's be clear here, not all liners are required to be insulated 100% of the time, however, it's considered best practice. The ICC code dictate only that the liner is listed as UL 1777 compliant and installed per manufacturer instructions. And yes, manufacturers test their liners without insulation when it comes to the codes.

As bholler mentioned, it's all about clearances. If the masonry chimney and surrounding combustibles are up to code, technically there is no requirement for insulation. However, this can be hard to prove a lot of times, so the assumption has to be made that it isn't up to code. If combustibles are up against the masonry (which is how zero clearance is tested in UL 1777 with 4" of masonry), insulation becomes a requirement to maintain UL 1777. This is also outlined in the ICC code.

My liner installation instructions outlined the clearance requirements for just the liner vs insulated and directly stated that insulation is not required for every application. Clearances without insulation are 0" to clay liner (specifically called the clay out), 2" from masonry to interior combustible, 1" from masonry to exterior combustible (for Canada: 0", 2", 1/2" respectively). Installing with insulation sets all clearances to 0".

I would actually be skeptical of a manufacturer that says all wood burning applications must have insulation. Why, liner not that good? Or just promoting best practice?

The vast majority of liner manufacturers that I've seen say use insulation as required. Some are better than others at giving what scenarios require insulation.

If insulation were required all the time, one of the chimney supply companies would have figured out by now that they should sell insulation with their kits...you know, to make it easier for customers to order, and to reduce liability coming their way.

 

[bholler]

And yes, manufacturers test their liners without insulation when it comes to the codes.

What liner manufacturers have taken and passed A test to get their liners listed for use with wood with no insulation? And what is the testing procedure for a lienr to be used with no insulation for wood? There is nothing listed in the ul testing procedures covering that

My liner installation instructions outlined the clearance requirements for just the liner vs insulated and directly stated that insulation is not required for every application.

What liner is that?

I would actually be skeptical of a manufacturer that says all wood burning applications must have insulation. Why, liner not that good? Or just promoting best practice?

So you are skeptical of olympia copperfeild and simpson liners? They say that because they are honest and are telling you up front that the liner will no longer be listed if it is installed with out insulation. And the fact that there are huge benefits to insulating and really no down side at all.

If insulation were required all the time, one of the chimney supply companies would have figured out by now that they should sell insulation with their kits...you know, to make it easier for customers to order, and to reduce liability coming their way.

It is not required for use with oil or gas which is what a large percentage of liners that are installed are used for.

 

[bholler]

But to be clear as long as you can confirm you have proper clearances from the masonry structure to combustible materials the entire lenght of the chimney there is no safety issue with an uninsulated liner. We will still never install one with out insulation due to the fact that it will not work as well and due to liability issues. But it would be safe.

 

[yooper08]

But to be clear as long as you can confirm you have proper clearances from the masonry structure to combustible materials the entire lenght of the chimney there is no safety issue with an uninsulated liner. We will still never install one with out insulation due to the fact that it will not work as well and due to liability issues. But it would be safe.

Exactly.

What liner manufacturers have taken and passed A test to get their liners listed for use with wood with no insulation?

Didn't say passed the test, just that they've tested them. Duravent comes to mind...saw it in their install manual and actually provided data. In terms of UL 1777 and clearances, this tests and certifies for only zero clearance to exterior masonry. Anything with a clearance no longer applies to 1777 (technically).

What liner is that?

Mine's a Selkirk. CSIA also acknowledges this for other manufacturers.

So you are skeptical of olympia copperfeild and simpson liners? They say that because they are honest and are telling you up front that the liner will no longer be listed if it is installed with out insulation. And the fact that there are huge benefits to insulating and really no down side at all.

Skeptical in the sense that it would make me pause and ask the question first. All the manuals I've read also say in some fashion that insulated is best practice and is UL 1777 compliant with insulation. But 1777 again is for zero clearance.

It is not required for use with oil or gas which is what a large percentage of liners that are installed are used for.

True, but my comment still stands. They'd still put a kit together for wood burners.

 

[bholler]

Didn't say passed the test, just that they've tested them.

So they are not ul listed for use without insulation when used with wood like I said. And since it is a listed component you are required to install it per its listing by code right? Now yes they are tested without insulation at the temperatures required for oil and gas installations but not wood. You keep forgetting that these instructions cover all fuels.

Duravent comes to mind

You mean the manual that says this

DuraVent Flex Liners venting solid fuel
heaters must be installed with a minimum
of one inch of TherMix
®
or with a ½" layer
of ProFoil or Flexwrap insulating blanket
between the outside of the liner and the
inside of the masonry shell to meet the
requirements of UL1777 or ULC-S635 at
zero clearance to combustibles.

So they clearly say there in order to meet the requirements of ul 1777 (which is required by code) You need insulation.

CSIA also acknowledges this.

Csia acknowledges what? And I read the selkirk installation manual and you are correct it does say that insulation is not required in all situations but those instructions also cover installation of liners for oil and gas where insulation is not required per its listing.

Skeptical in the sense that it would make me pause and ask the question first. All the manuals I've read also say in some fashion that insulated is best practice and is UL 1777 compliant with insulation. But 1777 again is for zero clearance.

What could possibly make you skeptical? And yes they say it is needed to be ul 1777 compliant. Now read code 1003.11 here (broken link removed to http://codes.iccsafe.org/app/book/content/2015-I-Codes/2015%20IRC%20HTML/Chapter%2010.html)
and then tell me if a listed stainless liner needs to be installed in accordance with ul 1777

True, but my comment still stands.

So you think that manufacturers should only sell liners with insulation even though when used for oil or gas there is no requirement for insulation. How does that make sense?

 

[Lake Girl]

bholler, ULC-S635 is the Canadian version. Wett inspector is trained using CSA B635. The level of inspection they perform doesn't guarantee that install is 100% as Level 1 is only outside visual which is required by home owners insurance or home buyers. Rather disappointing ... (broken link removed to http://wettinc.ca/LevelsofInspectionChart.pdf)

Interesting article:
http://www.orilliahomeinspector.biz...-oro-wett-inspections-home-cottage-commercial

NFPA 211 (Standard for Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances) is usually used in conjunction with building codes. NFPA site, you can sign up for account and view standard for free (only view no download).

 

[yooper08]

I'm not trying to argue here...I respect your experience in the industry, you have lots of insight.

We've already agreed (or so I thought) that if combustibles are zero clearance, we need to follow UL 1777 and make our install compliant with that, which means using insulation or whatever the mfg prescribes to meet the requirement. This is the exception under 1003.18.

If we install without the insulation, we must follow or ensure we're ok with clearances prescribed in 1003.18.

As for Duravent, no, that's not what I was referring to. I'd cut and paste if I weren't on my phone but keep reading, you'll find it.

As for 1003.11, it only says the lining system must be UL 1777 listed. It does not say it must be installed per zero clearance requirement, that falls under 1003.18 and the exception already discussed. As you know, 1777 also tests these liners for other things besides clearances.

Csia acknowledges that mfgs say insulation is not always required. Using Selkirk as the example, what I posted about their clearances is straight from 1003.18. Fuel type isn't the only variable.

As for what mfgs should sell, no, that's not what I'm saying at all.

 

[bholler]

Csia acknowledges that mfgs say insulation is not always required. Using Selkirk as the example, what I posted about their clearances is straight from 1003.18. Fuel type isn't the only variable.

Csia acknowledges that mfgs say insulation is not always required. Using Selkirk as the example, what I posted about their clearances is straight from 1003.18. Fuel type isn't the only variable.

We've already agreed (or so I thought) that if combustibles are zero clearance, we need to follow UL 1777 and make our install compliant with that, which means using insulation or whatever the mfg prescribes to meet the requirement. This is the exception under 1003.18.

Yes absolutely

If we install without the insulation, we must follow or ensure we're ok with clearances prescribed in 1003.18.

And where does it say that?

As for Duravent, no, that's not what I was referring to. I'd cut and paste if I weren't on my phone but keep reading, you'll find it.

Yes I read the section you were referring to also. It says

All temperature tests were performed on
chimneys featuring a 4” nominal masonry
shell and a DuraVent Flex Liner with or
without the specified insulation between the
liner and interior of the chimney (no clay tiles).
The outside of the chimney was surrounded
with a wood enclosure at zero clearance as
specified by the standard

It says with or without the specified insulation. for wood insulation is specified for oil and gas it is not. So again you are forgetting these instructions cover all fuels.

As you know, 1777 also tests these liners for other things besides clearances.

Yes but the listing for wood is only tested with insulation. And that means for wood it needs to be insulated.

Csia acknowledges that mfgs say insulation is not always required. Using Selkirk as the example, what I posted about their clearances is straight from 1003.18. Fuel type isn't the only variable.

Well yes csia aknowmedges that insulation is not required in all situation because it is not. It is only required for solid fuel burning appliances. And by the way how many csia courses have you taken of liner installs and code compliance? And yes know the clearance requirements very well and I completely agree that insulation is only required when clearances are not met by that code. But you are also required to install to the listing requirements. And for solid fuel the listing is for the liner with insulation.

 

[Highbeam]

You mean the manual that says this

DuraVent Flex Liners venting solid fuel
heaters must be installed with a minimum
of one inch of TherMix
®
or with a ½" layer
of ProFoil or Flexwrap insulating blanket
between the outside of the liner and the
inside of the masonry shell to meet the
requirements of UL1777 or ULC-S635 at
zero clearance to combustibles.

So they clearly say there in order to meet the requirements of ul 1777 (which is required by code) You need insulation.

I think you are misinterpreting the instructions and it is hanging you up. The key words in those duravent instructions are "at zero clearance to combustibles" which to a regular person means, if you don't already have a good chimney or right up against wood.

Sure, better safe than sorry you can always assume that every masonry chimney is built unsafely and sure, a liner with insulation will usually perform better but you are trying to convince us that insulation is required all the time and it's not looking to be true.

 

[yooper08]

It says with or without the specified insulation. for wood insulation is specified for oil and gas it is not. So again you are forgetting these instructions cover all fuels.

Fuel type isn't what they were talking about. They tested a wood application with insulation and no insulation. They then provided some data and a graph that showed the performance of insulated vs. not insulated in a zero clearance install...basically showing why you need to insulate in a zero clearance install.

And where does it say that?

1003.18...that's what defines the clearance requirements, doesn't it?

Let me ask a dumb question in regards to 1003.11. An approved lining material is clay. Is clay UL 1777 listed? Answer is no, hence needing to meet 1003.18. So why can't an un-insulated liner that is 1777 listed not be treated the same as clay? This seems to be the position of the manufacturers based on how they write their install manuals.

Nowhere in my Selkirk manual (or others I've read, including Simpson) does it say if connected to a wood appliance that insulation must be used. It only says insulation required to meet zero clearance. I read several of them trying to gather best practices across the different manufacturers before I had mine installed.

This is also what I've said CSIA acknowledges on their website (for wood burners specifically). Their caveat is that it can be tough to prove a chimney is in compliance to code, so their recommendation is to insulate. If they teach otherwise in their courses, that's not what the website says.

 

[begreen]

That is the crux of the issue. Uninsulated is ok in a completely compliant, tile-lined masonry chimney system, even if uninsulated is not ideal for draft improvement or creosote reduction. The problem is, how many masonry chimneys have code correct spacing from any combustibles? - very few, and that is the rub.

 

[Mr. Jones]

Speaking of block off plate. Just got done cutting and fitting mine ten min ago. Now waiting on liner to show up. I used tile backer hardee board. Couldn't find any steel around here that wasn't galvanized or zinc coated, or a big enough piece. Guess we'll find out how it works in a month or two.