Chimney Height & Altitude

[scotty]

I'm still looking for a replacement for our old pre-EPA Vermont Castings Resolute. Nothing wrong with that stove except it lacks the EPA compliance sticker on the back. So yesterday I'm down at the dealer looking at an Encore 1450 non-cat - which seems about right for size...., when I notice the chimney height graph on page 4 of the manual. They recommend a 16 foot chimney at sea level and an unbelieveable 50% increase at our altitude here. That would require a stove pipe as high as a three story building! Now I bet that every house in the Rocky Mountains has some form of wood heat, I know that VCs are popular stoves, and chimneys up here are no higher than anywhere else. Our air is only 10% less dense, and of course the proportion of gases is the same as at sea level. It beats me how VC could come up with their numbers. Does anyone have any idea? I wonder if their calculation is incorrect....My first impulse is to doubt it. Perhaps the graph was copied incorrectly when it was printed.

Are there any combustion engineers among us?

Here's the link to the VC manaual. The graph is on page 4. (broken link removed)

Thanks, Scotty.

 

[MountainStoveGuy]

from experence. 9000' needs at least 20' 8000' needs 18' 5000' works ok with 16' but i still try to get at least 18' for optimal performance at 5000' and 24' at 9000.

 

[Uncle Dave]

I'm still looking for a replacement for our old pre-EPA Vermont Castings Resolute. Nothing wrong with that stove except it lacks the EPA compliance sticker on the back. So yesterday I'm down at the dealer looking at an Encore 1450 non-cat - which seems about right for size...., when I notice the chimney height graph on page 4 of the manual. They recommend a 16 foot chimney at sea level and an unbelieveable 50% increase at our altitude here. That would require a stove pipe as high as a three story building! Now I bet that every house in the Rocky Mountains has some form of wood heat, I know that VCs are popular stoves, and chimneys up here are no higher than anywhere else. Our air is only 10% less dense, and of course the proportion of gases is the same as at sea level. It beats me how VC could come up with their numbers. Does anyone have any idea? I wonder if their calculation is incorrect....My first impulse is to doubt it. Perhaps the graph was copied incorrectly when it was printed.

Are there any combustion engineers among us?

Here's the link to the VC manaual. The graph is on page 4. (broken link removed to http://www.vermontcastings.com/catalog/elements/files/2007/30002425_Encore_NC_1450.pdf)

Thanks, Scotty.

I am new to Colorado, and am using an Old Lopi Patriot. I am not to happy with it. It came with the house. I come from Boston, Sea Level.

Thinking about this problem I have come up with the fact that as you go up in Altitude the air gets thinner. There are tables that plot this. At Sea Level the Presure is 14.7 Pounds per square inch. At 7500 Feet the pressure is 11.2 PSI. I would have to increase the Height about 5 Feet according to this to have the same mass in the flue that I had in Boston. It matches other things that I have read. My book calls for a Minimum of 15 Feet / Maximum of 33 Feet. I have 13 Feet by measure. It is very difficult to get any answers on this. A Manometer could measure the Draft. Then again Exactly what sort of reading should I look for? Not listed in my manual.

Dad would say, "If you do not have any 'Numbers' you do not know what you are talking about."

 

[EatenByLimestone]

Welcome to the forum.

I imagine a text documenting the science behind hot air baloons would work. Your stove is working off the pressure differential between the warm air coming out of the stove compared to the cooler air outside. The problems you face at altitude would be the same as a balooner trying to get over a mountain in the winter would face. There must be a calculation one could run to determine the amount of lift one would have at a certain air temperature.

Matt

 

[begreen]

Wow that's one from the wayback machine. Good to see MSG there. Hope Ryan is doing well.

 

[Uncle Dave]

Welcome to the forum.

I imagine a text documenting the science behind hot air baloons would work. Your stove is working off the pressure differential between the warm air coming out of the stove compared to the cooler air outside. The problems you face at altitude would be the same as a balooner trying to get over a mountain in the winter would face. There must be a calculation one could run to determine the amount of lift one would have at a certain air temperature.

Matt

Very few people could spell Schenectady. My dad used to work up in the hills to the east. However they did a lot of their formulas for Under Water work. Lots of funny ideas to solve problems such as this. Try to find out the volume of a glass bottle? After a day of calculation, the boss takes the bottle, and fills it with water, and pores that into a graduated cylinder. Edison. Actually you remind me that a friend works for Re/Max and has one of those Hot Air devices. Will have to ask. Tx