I'm sorta new to stoves and this has probably been discussed here before but there seems to be a lot of fisher knowledge here so I'm hoping for some advice. We have lived in three houses with stoves and have burned a lot of wood. Two Earth Stoves before that we loved. We bought a house last year with a crappy "High Valley" stove and I really don't like it. I have the opportunity to get a Grandpa Bear which I have heard great things about. Unfortunately my current stove has a 6 inch exhaust. Can I safely neck a Grandpa Bear down to 6". It goes into a stone double chimney and the stove is downstairs in a 2 story 2400 sq ft house with the chimnwy 4 ft above roofline. Is this advisable or should I look for a smaller stove. We burn wood regularly but also have baseboard heat throughout the house. Thanks
Fisher Grandpa Bear exhaust
- Thread starter wvuagr
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Some Some say they work fine on 6" I disagree I have seen problems doing it the smallest I would recommend is 7".
What is wrong with the highvalley they are usually pretty good stoves
One thing is that even loaded up with big locust it will barely hold a fire overnight and will not hold one if I'm gone 12 hours a day for work. The thing I really hate about it though is that everytime I open the door it pours smoke into the house. I've had the chimnet cleaned twice and it seems to draw well. If I unhook the pipe at the thimble and hold a lit piece of paper in front of th thimble it sucks the smoke right up the chimney. I also tried opening the door that is 5 ft from the stove to see if it just wasn't getting enough air but that doesn't help either. I had considered an outdoor air kit but since the door didn't make any difference I didnt think it would help.
Is it a cateletic stove or non cat? If it is have you checked the cat to see if it is clogged? How old is it? What moisture content is your wood.
It is non cat. It was purchased new in 01. The guy we bought the house from left all of the paperwork from the purchase. I havent testes the moisture in the wood but it is all locust, oak, and cherry that has been stored indoors for over two years.
I too need this very same info. Basically same info. My "thimble" thru to the chimney (through brick) is a 6 inch very thick pipe. But I have an 8 inch Grandpa bear. My chimney is in the center of home, brick, with four "holes", three serving other appliances. There is a fireplace behind the stove, but it is sealed with metal fabricated doors. the liner is tile, has been inspected and is okay for use. It is not "insulated" but it basically holds up the whole house, a raised ranch, circa 1950. Mine stov is top vent, the pipe will go up about 26 inches and 90 to the "thimble" which is 28 inches long, exiting in the chimney. Previous woodstove, a Warm morning, worked fine. I really want to avoid having to punch out for an 8 inch thimble...
I only have 7 inches to ceiling from pipe, which will have a metal covered cement board with 1" drop, non-combustable. Good?
I only have 7 inches to ceiling from pipe, which will have a metal covered cement board with 1" drop, non-combustable. Good?
By code, (NFPA 211 Standard that codes are written from) you can't reduce more than 1 inch, but the ICC code PA is under now does not allow any reduction.
If the flue was 6 inch insulated all the way, there is a good chance of it physically working fine. Make sure the 28 inch horizontal run is pitched upward 1/4 inch per foot. It should not be flat. That reduced length acts like a damper being partially closed which is a restriction. It makes it slow starting, can smoke back when doors are opened and generally won't have the full flow capacity like an engine not having full throttle or a restrictor plate preventing enough oxygen and fuel to be burned for maximum output. The most important is the diameter of the existing flue you are using. It should not be larger than the 8 inch stove outlet or 50 1/4 square inches. Larger diameter allows flue gasses to expand and cool, requiring you to leave more heat up chimney to keep internal flue temp above 250* to the top. A larger flue area that needs more heat left up prevents you from adding a more efficient baffle plate in the firebox, which allows the stove to radiate more heat into the home as well as burn cleaner, reducing the probability of creating creosote.
If the flue was 6 inch insulated all the way, there is a good chance of it physically working fine. Make sure the 28 inch horizontal run is pitched upward 1/4 inch per foot. It should not be flat. That reduced length acts like a damper being partially closed which is a restriction. It makes it slow starting, can smoke back when doors are opened and generally won't have the full flow capacity like an engine not having full throttle or a restrictor plate preventing enough oxygen and fuel to be burned for maximum output. The most important is the diameter of the existing flue you are using. It should not be larger than the 8 inch stove outlet or 50 1/4 square inches. Larger diameter allows flue gasses to expand and cool, requiring you to leave more heat up chimney to keep internal flue temp above 250* to the top. A larger flue area that needs more heat left up prevents you from adding a more efficient baffle plate in the firebox, which allows the stove to radiate more heat into the home as well as burn cleaner, reducing the probability of creating creosote.
Todd67
Minister of Fire
Are you saying that 4 different appliances are using the same chimney? Refer to the line above that I underlined in the quote...
When you say you had it inspected what ever inspection did you have done? Did they scan the flue? Did they check for required clearances? And if it was me I would drop the thimble regardless
Sorry I was not more clear. The brick chimney is a 4 holer...with 4 separate flues encased in brick and masonry, an affair that is about twelve feet by 6 feet at the base. None has more than one "appliance". two are fireplaces (first floor and basement) a gas furnace in one and a HW gas tank into other. All are lined with tile, surrounded by about five layers of brick. Long story but the guy who built it was "unique". The one that I would use for this application has a fireplace but it is sealed with metal doors and the flapper system is closed. Makes it easy to sweep! The "thimble" is simply a pipe liner thru the brick masonry into the flue, so it is smooth. I guess I could simply use the stove pipe....
Currently the 6 inch ipe is 10 inches from ceiling with a suspended cement board between it. If I go 8 inch, I will punch a new hole lower, seal this one.
inspection included a scrubbing (it was very clean) and a scope. No issues. It was not reviewed for the use of the wood stove because at the time I was thinking pellet. I have changed my mind cause we lost power 4 times in 18 months. Going back to the woodstove.
The flue is a 7x9 if I recall correctly (rectangle). Not huge. Cappedwith a lid/screen spark arrestor on top.
Thoughts? BTW, I never see me using the stove "open". Not into looking at a fire, just want warm...
Currently the 6 inch ipe is 10 inches from ceiling with a suspended cement board between it. If I go 8 inch, I will punch a new hole lower, seal this one.
inspection included a scrubbing (it was very clean) and a scope. No issues. It was not reviewed for the use of the wood stove because at the time I was thinking pellet. I have changed my mind cause we lost power 4 times in 18 months. Going back to the woodstove.
The flue is a 7x9 if I recall correctly (rectangle). Not huge. Cappedwith a lid/screen spark arrestor on top.
Thoughts? BTW, I never see me using the stove "open". Not into looking at a fire, just want warm...
Todd67
Minister of Fire
Thanks for the clarification on the chimney, sounds very robust, in a good way. I'm right there with you on having a woodstove for those power outages.
I'll let the installation experts advise on your questions. Pictures of your layout really help us visualize what you are describing.
I am having my chimney guy come to consider a lower thimble run, 8 inches in diameter. Of course the present one will be sealed. The thought of again (did it when I was 10 or 11 with my dad) punching a hole 28 inches thru masonry with a power chisel if NOT attractive t o me! Ugg.
Similar threads
