Originally posted by Don Jordan, National Certified BOCA Local Building Inspector and Mechanical Inspector.
Some background:
In the late 60s to late 70s most stoves that were built were not regulated or tested. UL approved stoves did not become common until 1979. Note that UL tests are often performed by other labs such as
Warnock Hersey, Intertek and Omni.
UL testing is for safety, which the newer EPA testing regulates pollution and efficiency. Every EPA stove has to meet high efficiencies (60-80%) and produce very little pollution and creosote. Many earlier stove models operated at 35-50% efficiency and produced dangerous amount of creosote - making chimney fires a common occurrence. In anticipation of complying to the upcoming EPA certification, the late 80 stoves became more efficient.
IMPORTANT: LOCAL CODES AND STANDARDS MAY VARY AND IT IS ENTIRELY POSSIBLE THAT IT IS AGAINST CODE FOR YOU TO INSTALL AN OLDER STOVE THAT IS NOT UL AND/OR EPA TESTED. CHECK WITH YOUR LOCAL BUILDING OFFICIAL.
Woodstove installations require a building permit. Many insurance companies also require UL listing and a certificate of inspection from your local inspections office. In MA and some other states,
Carbon monoxide detectors are also required as part of the installation.
Based on the above, stoves prior to 1980 are generally eliminated from installation in residential dwellings. Such stoves are likely to need extensive work and parts and advice will be difficult or impossible to find. Just as with vehicles, your best bet is to look for something made within the last 15 years that has not been over fired or otherwise abused.
So what to look for? What questions one should ask and tell tale signs of abused stoves?
Other Questions: How was the stove used? How old is it? Do you have the manual? When was the last maintenance done, and what was done. If a cat stove, when was the cat replaced? Why are you selling? Ask if the stove has been over fired?
Look for brand name stoves, where the manufacturer is still in business. Confirm that the stove is UL labeled. Look for the testing agency and EPA certification. All stoves should have an attached label, although time and use can make them unreadable or they could have burned or fell off.
Metal Fatigue
Remember heat can change the properties of metal. One has to look for metal fatigue. First tell tale sign: look around the stove If you see a whitish color half way up the stove on the sides or back that is an indication of metal fatigue. Rust is another sign of metal fatigue. There is a difference between light surface rust and flaking scale type. Take particular notice if heavy rust or scale like rust exists.
Open up the doors look around are the fire brick cracked or crumbling? A few small hair line cracks are normal, large cracks or bricks powdering are signs the stove was heavily used, but they can often be replaced for a few dollars apiece. Look at the metal - do you see warpage or cracks? Over firing accelerates metal fatigue. If you see any of the above evidence of metal fatigue or over firing, you may want to reconsider the purchase. It might be wise to see if parts are available to replace the fatigued liners or baffles.
Note: Steel and Cast Iron are the most common stove materials. Stoves made of steel are usually welded together as to become one piece, and parts - with the exception of firebricks and gaskets, cannot be easily replaced.
Cast Stoves are built from numerous separate parts which are bolted and cemented together. These parts can often be replaced, but you should check the availability and price. Also, consider whether you are handy enough to do the work yourself. Having a pro rebuild a cast stove can easily run $500 plus parts.
Door Latches and Gaskets
To check for leaks, use the light bulb test. Place a 150-watt light bulb in the firebox and close the door. Walk around the stove looking at all seams, gaskets, and look for light leaks, the light also can highlight a crack you may previously missed Look under the stove in back. If you see light coming out the seams, thats an indication of needing some gasket, furnace cement or possibly a total rebuild (if stove is cast-iron). Light around gaskets means new gasketing is required...an inexpensive fix. With the light removed, employ the dollar bill test to check door seals. Place a dollar bill between the gasketed closed doors If you can pull it out easily without resistance the gaskets need replaced or the door latch needs adjustment. Move the dollar bill around to multiple spots where the gasket contacts the door frame.
At this point if all checks out, you have done your best to determine if you have found a decent wood stove.. Another consideration is to size the stove to the area you are trying to heat. Please read other articles and posts on Hearth.com considering locations and venting issues. If you are hiring a qualified installer, request that he inspect the stove before installation Your life could depend on it. Finally if all goes well you local inspector will approve your stove and installation...
Need more information? Go to the Hearth.com Forums and upload a picture or other information about the model you are considering. One of our many experts will offer an opinion and help.
Garage Installation?
Can't be done! According to
NFPA 211 Chapter 9 - 9-2.4 :
Solid fuel-burning appliances shall not be installed in any residential garage.
I hope this guide will help potential purchasers from making a costly or potentially deadly mistake.
Added - Begreen 8/15/08 -
If you want to know more about buying a stove in general, also see these articles:
http://www.hearth.com/econtent/index.php/articles/choosing_a_wood_stove;Used_Stove_buying_Primer
