Chimney liner for oil fired boiler

[anthonymmfalcone]

Dear Readers,

I've a Burnham MPO boiler. I called Burnham, whose technicians suggest that I take the most conservative approach and line my existing exterior-wall, clay-lined brick chimney with a stainless liner to minimize flue condensation.

Should this liner necessarily be insulated as well? Or is the dead airspace (although somewhat cold due to exterior wall) in the chimney a sufficient buffer? I know the most conservative answer is to insulate the liner too, but your experiences would be appreciated as this insulation would be yet another expense on top of the liner.

Thank you very much for your responses.

-Anthony

[Don Ocean]

Heh! Heh! Size does matter... ;-)

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[ransley]

If it heats water its a boiler, if it heats air its a furnace, so you have a boiler from your next post. If its a condensing unit you should be able to vent through a wall, I dont understand why you need to line a clay lined chimney unless its falling apart, clay is durable.

[Bob Pietrangelo]

Mortar is not

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[Bubba]

Thats why you dont do HVAC. Most chimneys were designed long ago with a big ol flue to handle those huge gravity furnaces that ate large amounts of gas when no one cared how little it cost. Now gas is expensive. People are using furnaces that dont require a huge chimney. They need a smaller one so the flue gasses dont condense in the chimney and destroy. Thats why you line them with a smaller flexible flue or a b-vent flue. Thus, effectively reducing the size of the chimney and preventing condensation where it doesnt belong. Things becoming a little clearer now, ransley? Bubba

[Zyp]

Anthony;

Check with the Burnham Tech's again, I believe they intemnd for you to use a double wall stainless flue pipe in the chimney opening. Insulation not needed.

[ftwhd]

Are you a moron or do you just play one on the internet?

PS dont cross post this HO shit to alt.hvac

[Don Ocean]

I say again.. Size does matter. That chimney must be resized to fit the venting requirements. A liner is one way to downsize for modern equipment needs. Check your local building authority if you don't have a code book.

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[anthonymmfalcone]

Just called them again. They expect stack temperatures of below

350F. Considering it's an exterior wall chimney and (I suggested I may also have a fresh air duct installed in the future), they once again recommend a stainless liner to prevent condensation from damaging the existing chimney. As they're not in the liner industry, they did not want to officially comment on the specific type, although the individual I spoke with said he's familiar with the single wall variety.

The double wall stainless liners I'm familiar with would seem like overkill: they are insulated in between layers and are typically the type that can be in close proximity to combustibles, like those metalbestos things. And I do not want to switch to a power vent situation.

Any 3-pass boiler (Buderus, Burnham MPO, etc) experts out there familiar with or observe a similar stainless chimney liner installation??

[Noon-Air]

What does the installation manual say about it?? What do your local codes require?? What did the local building inspector say about it?? What did your insurance company say about it??

We are not here to do your homework for you.

[anthonymmfalcone]

Thanks for the suggestions.

1. Installation manual says use a liner "if condensation is observed." Per my earlier post, I called the manufacturer and didn't get too much advice on what type as it's not their product.
2. I didn't think to check the code! Chapt 8 of Mechanical Code of NY says to use liner that will resist condensate, and is in accordance with NFPA31. I'll find NFPA31 and see what it says. Hopefully will provide guidance on insulated vs. non-insulated.
3. Local building inspector cannot (legally) suggest anything beyond the building code, so I'll need that NFPA31.
4. I didn't check insurance company. Not sure if they'll even understand what I'm saying. I'll try.

I have two additional thoughts:

1. if flue gas is cooled too much within liner inside chimney, it may not create sufficient draft up the 25ft tall, exterior wall chimney. Is there a way I can estimate if I'll have sufficient draft? Reference would be appreciated.
2. if flue gas is cooled too much and condensation occurs within the liner, is it such a big deal? It would just drip down, through the bottom tee, and into the cleanout chamber. In other words, the system would work as expected, no?

In the meanwhile, any other suggestions or experience is appreciated.

[Zyp]

So it doesn't say in the maual to use a flu chimney Type B vent? It doesn't give you a GAMA guide? Interesting.

[Noon-Air]

Whadya want from E-Bay??? You expect to ge the install manuals too? sheesh.