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Fisher GrandPa Installation (great stove-pipe)

Post in 'Fisher Stove Information, Parts, History and More' started by Ski-Freak, Sep 30, 2012.

  1. Ski-Freak

    Ski-Freak New Member

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    I'm the third owner of this ski house and have owned it for the past 7 winters. The house was initially built in 1978, and I believe the stove was installed then. It has a great stove-pipe installation which puts out plenty of heat and burns quite clean too:

    Stove Pipe.JPG

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  2. pen

    pen There are some who call me...mod. Staff Member

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    I grew up with fisher stoves, they throw heat!

    Couple of things to consider:

    1. Is there a 1 inch air space between that brick and the (assumed) wooden framed / drywall wall behind it? If not, it looks like it's too close to the brick.
    2. Is that an angled joint up near the transition through the ceiling? If so, is that joint 18 inches down from the wooden paneling above it? If not, it appears to be inside of appropriate clearances for safety, even for intermittent use.

    BTW, from that single pic, it looks like a great abode! I'm jealous (kids keep me from getting on the slopes much anymore). Welcome to the site!

    pen
  3. Ski-Freak

    Ski-Freak New Member

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    Great and very pertinent questions!

    There's some kind of fibreboard behind the bricks. Since the house was built in 1978 it's probably asbestos fiber based board. That probably met the applicable codes back then. I'm pretty sure the Fisher GrandPa and the entire 8 inch stove-pipe/chimney was also installed back then in 1978, and that it has been used continuously by myself and previous owners. Also at least one previous owner rented this ski-house out extensively as well, and renters are generally not too careful running stoves. In addition to 34 years of continuous use not indicating any safety shortcomings, and that asbestos is a hassle to uncover, I'll most likely let the bricks be as grandfathered to any codes.

    The interior stove-pipe is another story though as it has some rust on it in a couple spots, and the back-to-back 90 degree couplers just below the collar at the top of the photo are really hard to run a brush through. I'm going to remove and replace the whole interior stove-pipe as it's 34 years old, and I want to upgrade to back-to-back 45 degree couplers instead to make brushing easier (draft has always been fine so that's not a concern). I will now keep in mind the clearance issue at the top of the interior stove-pipe couplers near the collar, so thanks for mentioning that! The choice will be whether to use 22 Gauge or 24 Gauge stove-pipe and couplers, and there appears to be a trade-off in that decision. While thicker (22 Gauge) would be some degree safer in the event of a chimney fire, and has a more forgiving 10" clearance requirement instead of an 18" clearance requirement, it also doesn't release as much heat into the room as thinner 24 Gauge pipe would (thus its 18 inch clearance requirement). Maybe that's good from a chimney perspective as it will carry more heat into the top 8 feet of insulated chimney pipe that's above the collar just visible in the picture. However, IME this chimney has actually run pretty clean over the last 7 winters burning up to 1 cord per winter, so maybe it won't run as clean doing more cooling in the top section. BTW, the top 8 feet of insulated chimney pipe above the collar at the top of the photo is inside a large insulated chimney structure alongside the roof. I have only brushed this chimney 2 times over 7 winters as it has NOT had a large build-up.

    I'm also in the process of building a fire-box baffle inside the Fisher GrandPa stove just below the pipe exhaust, which could make it run less smokey. It might also make the stove-pipe a little cooler.

    Any thoughts on using 22 Gauge versus 24 Gauge interior stove-pipe?
  4. Ski-Freak

    Ski-Freak New Member

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    Planning to use an 8 inch one of these Snap-Lock Draw Bands to make the connection from the new interior stove-pipe to the outlet on top of my Fisher GrandPa:
    Stove Pipe Draw Band.JPG

    Hoping this gets around any potential size mismatch between the stove-pipe and the stove outlet.
  5. Danno77

    Danno77 Minister of Fire

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    Where in the world are you and when can I come skiing?

    edit: Western Rhode Island. I didn't read your signature.
  6. Ski-Freak

    Ski-Freak New Member

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    I wish we had snow! Ski house is in the White Mountains of New Hampshire, but no snow yet this year. It's leaf peeping time now...
  7. coaly

    coaly Fisher Moderator Staff Member

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    I'm not sure where you got the 10 inch clearance for 22 gauge pipe, ANY single wall connector pipe to my knowledge is 18". Only double wall pipe has reduced clearance.

    The ignition temperature of wood becomes lower as it is dried out over the years in an installation that is borderline close. It may never have been a problem, but the wood, even behind shields and cement board becomes carbon from the prolonged heat, and ignites much easier than it would have in prior years.
  8. Ski-Freak

    Ski-Freak New Member

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    OK, in response to some questions there are two things I've recently researched:

    1. The clearance between a wood stove and a 3.5 inch thick masonry wall WITHOUT a 1 inch backing gap is 12 inches, so we're good there. The 1 inch backing gap reduces that clearance further but doesn't matter since we're over 12 inches. Interesting point you made about the heat over many winters of woodstove heating drying out the walls, in effect cumulatively degrading clearances, but IMO you would also need to take into account the many summers of high humidity in-between when the stove doesn't run replenishing at least some of that lost moisture. Also, being an engineer I would expect that a safety margin for any cumulative drying effects was taken into account when establishing the original requirement, so attempting to account for it now would be double dipping (redundant).

    2. For 8 inch stovepipes I have read that 22 Gauge cold-rolled steel (e.g., HeatFab or Saf-T Pipe stovepipe) uses 25% thicker metal than 24 Gauge steel, which runs cooler externally and reduces the combustible wall clearance requirement from 18 inches to 10 inches. Double wall pipe runs even cooler externally and further reduces that clearance to only 6 inches.

    The challenge here is that there are instructions, guidances, and requirements out there from numerous sources such as municipalities, insurance companies, safety agencies, etc., and they are NOT consistent with one another. In the end, I would proffer that an installation which has successfully stood the test of 34 years cannot be simply discounted. FWIW this installation is insured albeit there is an annual surcharge applied to the policy premium each year because I could not provide a UL listing number for the stove, which pre-dates UL listings..
  9. Ski-Freak

    Ski-Freak New Member

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  10. coaly

    coaly Fisher Moderator Staff Member

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    Regulatory agencies in the US use the NFPA 211 standards for consistency. These are not codes, they are standards that codes are written from. Most municipalites and insurance companies don't write their own, they adopt NFPA 211. The standard also contains criteria for non-listed stove installations commonly called generic standards. This is where the 36" to combustible, 18" to single wall, 6" to double wall comes from.

    The connecting clamp type band shown looks like it goes on the outside of the pipe and stove collar?

    All connecting pipe needs to be installed crimped end down into the pipe below it. 3 screws are required at each joint.
    The pipe needs to be crimped and inserted inside the stove collar due to condensation dripping back into the stove, never outside the pipe or onto the stove.

    Selkirk Saf-T-Pipe is the HeatFab product; http://www.selkirkcorp.com/heatfab/product.aspx?id=7186
  11. Ski-Freak

    Ski-Freak New Member

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    Really? Then I guess the double female stove-pipe to stove-flue connector that has been in place for the past 34 years of operation with NO problems whatsoever was installed either in error, or before what you're talking about became some common practice. I suspect that the codes don't address this issue either:

    Double Female Connector.JPG
  12. coaly

    coaly Fisher Moderator Staff Member

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    Any flue below it's condensation point will condense water, a byproduct of combustion along with creosote and run out the joints. It is unsightly, stinks, and can make a mess on the stove top. You have ran it hot enough with seasoned wood to prevent moisture running out. Some day you won't be so lucky and you'll find out if this fluid is a combustible mixture on a 600* stove top.
    http://www.hearth.com/what/guidelines.html

    http://www.msue.msu.edu/objects/con...sion_id.499646/workspace_id.-4/01500596.html/

    Yes, the NFPA Standard addresses this. The standard states; All installations are to follow manufacturers installation instructions. Your manual, on page two under pipe direction states; either way giving pros and cons. "Male end-down installation; Directs creosote or condensation back into the stove and is consumed. Some chimney manufacturers, such as Dura-Vent, make pipe and adapters that connect easily and maintain an internal drip free male connector down configuration".

    Read step 4 of pipe installation here;
    http://www.duravent.com/docs/product/L122_DuraBlack_June2012_W.pdf

    The manual after 1980 for UL listed stoves states "Install the chimney and accessories according to the instructions provided by the chimney manufacturer". So the instructions from the chimney manufacturer become part of the code as well.
  13. Ski-Freak

    Ski-Freak New Member

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    OK then, it's becoming a bit too complicated to undertake installing a new stove-pipe for this winter. Instead I just cleaned up the light surface rust spots on the original stope-pipe with emery cloth, and polished the stove-pipe and GrandPa stove with Rutland Stove Polish (a paste of wax and black color). Looks fine for yet another winter!

    Thanks for all of the suggestions, I'll keep them in mind when I undertake this project next summer
  14. Ski-Freak

    Ski-Freak New Member

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    I installed my new home-made baffle in the GrandPa firebox below the top flue exhaust and then burned off the waxy part of the stove polish. The polish smoked a little for the first half hour and even though I had two windows open the nearby smoke detector went off - however, it didn't look smokey in the room (but you could smell the wax burning). What was particularly interesting to note was that the stove-pipe temperature ran noticeably cooler and was also more stable with the baffle installed, as indicated by the stack thermometer in the pictures above. There seemed to be a little less smoke coming out of the chimney, and the top of the stove seemed hotter as the water in my steamer was boiling more rapidly than usual. This is all good! Here is what the installed baffle looks like:

    Fisher Baffle Installed.JPG

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