Excell 2200 chimney questions

[LarryD]

Here goes!!

I bought an Excell 2200 earlier this year. We are having a pretty large addition being built and it seemed like a good time to go from a stove to a boiler. With that said, as I was prepping for the install next week and I noticed that our existing chimney is NOT 8X8 like I thought it was. It is 6X10. I also am questioning the integrity of the tiles, which would have been not a huge issue if it were an 8X8. I figured worse case I can put a 6" round liner in the chimney. I spoke with my builder and we have decided to (for several reasons) to knock the old chimney out of the chase in the existing part of the house and start over. The existing chimney serviced our antique 50 year old oil fired boiler. So here is my question. I still have 24' of Metal Fab 6" class A pipe. Will this work? The chimney will be int he center of the house. The Tarm manual (I think) is a bit vague. In one spot it say's 8x8 and in another it say's 6" round is ok. Does anyone have any experience with 6" round class A pipe inside the heating envelope of the house, 24+ feet in length? We live in central CT if it matters.

Any thoughts, suggestions, feedback is appreciated

LarryD

 

[webbie]

The flue collar size is 6" on that unit so I don't see why you would have to go much bigger - given a tall chimney.
Even the 6x10 is fine if in good condition. If not, you can line that chimney in a number of ways - they even make rectangular flex pipe designed to fit down it.

As to a 6" round class A, I would give Tarm in NH a call. It might be that you should use the smaller oil nozzle if so, because you still have to have the chimney capacity to output the entire (both fuels) output of the boiler. So you EITHER need a tall chimney or a wider chimney or both. As an example, lining the 6x10 with a 5x9 interior flex would be 45 sq inches of flue space, which is quite a bit larger than 6" round.

 

[taxidermist]

The flu collar size is 6" so I would say 6" insulated pipe is the way to go But the best way to know for sure is get in touch with Tarm.
(broken link removed to http://www.woodboilers.com/product-detail.aspx?id=47)


Rob


edit.... Webmaster beat me to it

 

[BrownianHeatingTech]

According to the manual...

The boiler "may" operate on a flue as small as 6" round, but recommended size for the Excel 2200 is 8" round or 8x12" rectangular.

Using a smaller flue may work for you, or may not. It's up to you as to whether you'd like to take the risk that it might not...

Joe

 

[webbie]

The "may" relates to the draw and capacity of the chimney.....meaning Tarm has no control over whether a chimney is only 15 feet tall and has 3 bends in it. It may also not work with with a 15 ft 8" chimney like that.

The enclosed chart shows an example of chimney sizing.....

Example: Tarm 2200 300,000 total input (both fuels working at same time).....
7" chimney (equiv of lining the existing 6x10)
2 elbows
.07 draft needed (guess)

OK, so that would be the 300 row and 7 - going over to .07, we see the chart specifies 12 feet. We have to add 2x3ft to that for the elbos (see 3rd column) - for a total of an 18 foot 7". So a 24 foot is certainly fine.

Using 6" for the same calcs:
12.5 ft of chimney plus 9 feet to make up for els = 21.5 feet required.

So the real answer is that the amount of turns may have more to do with it than the chimney size. In either case, this is a realistic chart for Class A chimney. It's always good to EXCEED the requirements as opposed to exactly meeting them, but it looks like you can do that in either case.

 

[LarryD]

Thanks for the replys. The boiler exits out the back so it would only have one 90* elbow. So worst case I can use the pipe I already have. Craig, you've mentioned 5x9 flexible liner. I have searched and can't seem to find a manufacturer that makes it. Do you know of one that does? One other thing I need to consider is that this is a part of a bigger project and I cant hold up a $225,000 project. It may just be easiest to use what I have. On another note, what is the down size of haveing too small a chimney with an Excell 2200? Is there a weather situation that it might manafest itself more in?

Thanks for all the help

LD

 

[LarryD]

I have done some searching and can't find an answer. Why do you need to insulate a liner? It would be going in an existing cement block and tile chimney. Is it due to condensation?

LD

 

[webbie]

Insulation is mostly to help bring a chimney that is built wrong (no liner, no clearances, etc.) up to the higher newer standards. The standards have changed over the years.

Quote a few manufacturers make rectangle -
see:
(broken link removed to http://www.nationalchimneysupply.com/Chimney-Liners.aspx)
(broken link removed)

etc.

this is OD: Outside Dimensions: 6” x 9 3/4”

An alternative would be to have 7" or 8" flex ovalized, which some companies can do for you.

As far as too small of a chimney, based on all our calcs so far this will not happen. Also, we are figuring in a lot of slop - for instance, we are assuming wood and oil burning at the same time at almost full blast - that is unlikely to be the normal situation. Still, I think you should use the chimney chart and exceed the 300,000 BTU specs - which should be easy.

Note, some of those chimney makers only sell wholesale, so your builder or mason or contractor may have to make the final sale.

 

[LarryD]

Thanks for everyones help. We have decided to "demo" the existing masonry chimney and install the 6" Class A pipe that we have from our wood stove. The big factor in our decision was we need to work with what we have. I couldn't imagine getting my hands on an appropriate liner in short order. So we will put up with the expense and mess of our decision. We haven't even gotten to installing the boiler yet!

LarryD