defiant 1975 wood stove

[tonyb]

i just built a cabin in montana an my nabor gave me there old defiant wood stove, can sombody tell me about it? my cabin is about 1500 sq. ft. how dose the damper work? should iclose it when i get a fire started? should i put fire brick in it? should i get a great for it? i put all new gasgets in it. an shined it up real nice, but i dont know if it will heat up my cabin good, will it? can i load up the fire box? it has a side loader an the doors open up in front. but ill keep doors shut. i cleaned it out the best i could with a shop vac. it has no cracks in it, an is in good shap, tell me the best way to use it please, thank you , tony

 

[begreen]

It will help to read up on this stove's operation. This is a very serious heater so be sure that it has lots of room from combustibles and has a proper flue connection. Until you learn the stove better, just run it with partial loads of fuel. When the fuel is burning well, engage the bypass for a burn regulated by the thermostatic air control.

The best place to start is to read the manual for the stove. It's posted in two parts as pdf files here:
https://www.hearth.com/econtent/index.php/wiki/Vermont_Castings_Older_Stove_Models/

You might also find some helpful information in this posting. It is not for the defiant, but the operation is similar:
https://www.hearth.com/econtent/index.php/wiki/Operate_an_older_VC_Resolute/

 

[southbalto]

My dad has a late 70s defiant heating his 3000sqft home. The thing truly is a beast. You can put huge loads in there an it will really crank the heat.

It's a really good idea to put a key damper in the pipe behind/above the stove. We've found it to be the best way to control the burn. Leave it wide open at startup with the side door cracked....It will roll right up to 500-600 and beyond. Once you get to the temp you want, close the door and close the key damntper gradually.

Fantastic stove...

 

[branchburner]

My Dad has one as well. We found if you let the thermostat close off the air supply, the stove truly becomes airtight, and will produce a lot of creosote due to incomplete combustion (even with dry wood). So be generous with the air - it's much better to burn small loads with sufficient air than to try and suffocate a large load of wood as a way of controlling heat output. A full load may heat you out of the place.

A pipe damper might help - we never tried that. The bypass damper should be shut only after the fire has been going for a while and you have a bed of coals started, otherwise it will have the same dampening effect as closing the air. If you burn good, dry wood and don't try to get slow, smoldering burns you should keep the pipes clean, but check often to be sure.

A quick note on startup with the side door cracked - do not walk away from your stove leaving it like this. It is very useful for the first few minutes only, but results in a dangerous blast furnace if you happen to forget about it!

 

[94ranger55]

I have the defiants smaller brother the vigilant .....these stoves are ment to throw some heat takes some time getting use to running it ,but once you get that down they are great....also they are meant for over night burns ! The Vigilant holds 60lbs of wood,the defiant can hold 80lbs acording to the VC manual !

 

[fjord]

My Dad has one as well. We found if you let the thermostat close off the air supply, the stove truly becomes airtight, and will produce a lot of creosote due to incomplete combustion (even with dry wood). So be generous with the air - it's much better to burn small loads with sufficient air than to try and suffocate a large load of wood as a way of controlling heat output. A full load may heat you out of the place.
A pipe damper might help - we never tried that. The bypass damper should be shut only after the fire has been going for a while and you have a bed of coals started, otherwise it will have the same dampening effect as closing the air. If you burn good, dry wood and don't try to get slow, smoldering burns you should keep the pipes clean, but check often to be sure.
A quick note on startup with the side door cracked - do not walk away from your stove leaving it like this. It is very useful for the first few minutes only, but results in a dangerous blast furnace if you happen to forget about it!

Ditto. Read the link that BeGreen put up. Worthwhile for the complex schematic. The Defiant was one of the classic wood burners of the 70's wood stove renaissance by the original Vermont Castings' crew in Vermont. There must be 1000's of the tank still in use.

Adding to the above: be sure that your primary air thermostat is operating fully. You've done most of the work getting the beast up to specs. Unless you have excessive draft, a damper is not needed; it will help create creosote and prevent flue cleaning.

We heated for years with the Defiant's smaller brother, Vigilant ( nice ship names ). The bypass damper is flipped on when you get a good burn going for recirculation of the gases like Branch B says. THEN, once the temp starts to rise again, lower the air control to what you want. It's the same principle of operation as the later VC catalytic stoves. Great burner....definately not a 'smoke dragon'.

 

[branchburner]

THEN, once the temp starts to rise again, lower the air control to what you want.

This is the tricky part - we would always set the thermostatic air control too low, only to find later the stove had gotten hotter and automatically reduced the air input further. This would sometimes slow the fire to a smolder, which would have the desired effect of reducing the heat output, but also have the undesired effect of producing lots of smoke and creosote.

 

[formula_pilot]

Old Defiant, great stove. I found small fires in the Defiant burn much better they are built deep in the right side of the stove, near the baffle. Will allow going in bypass (secondary) mode much faster and burn clean longer. +1 on avoiding full loads with the air choked off, will make creosote.

 

[spirilis]

yup it's a serious heater, check the air control on the left side if it has a box over it with a label it might reveal the actual build date. the fireback always says 1975 even mine (mine's from 1980, and is one of the first runs of the "Defiant II" but its fireback says 1975 too)

best to mate it with a well drafting interior chimney if you can. if you can make use of the downdraft combustion secondary burn system (that baffle control above the side door) you should get decent efficiency out of it. Note the secondary "air supply" is that little round slide-open control next to the side door... gotta open that up if you use the downdraft combustion damper, but keep it closed when you're not (it supplies constant intake air and will defeat the purpose of the thermostatic primary air control when you're using the stove in normal "updraft" mode)

common problems I've heard about:
1. thermostatic air control broken, i.e. the bimetal spring doesn't work right. It'll be obvious once you get a good load of wood going as it should start to automatically close the flap once it's up around 600 degrees on the griddle plate if it's working properly. If it never closes off and the temp stays up in the 600 or 700F range for an extended period of time then it's probably broken.
2. fireback cracking - if it's truly an older (Defiant I) model it's got a 1-piece fireback that might have cracked. newer ones are a 2-piece fireback and more resilient I guess to cracking
3. failed divider between the secondary air chamber and the flue exit - this is one thing that will prevent that "downdraft secondary combustion" system from working properly. the actual barrier between the secondary air chamber (which must extend from the left side of the stove all the way to that mysterious chamber on the right side) and the flue path above it is a couple ribs in the cast iron fireback+rear casting with some steel mesh and furnace cement sealing it up. if it hasn't been rebuilt since it was new it might have failed but hard to say. That's why when setting up the stove you must make sure it has adequate draft, follow the recommendations in the manual and make sure the chimney's tall enough as a lack of draft will prevent the downdraft system from working right too (and make it difficult to troubleshoot why the downdraft combustion isn't working). A member here "fbelec" has good experience with these stoves, he said if the downdraft secondary combustion is working properly, you can stare down that small round secondary air opening (if it's dark with the lights out) and see a blue flame at the distant end.

note that if the downdraft combustion setup doesn't work right, it's not the end of the world, you can use the stove just fine with the damper open and even closed (although it won't burn cleanly at *all* without the downdraft combustion working), it's just a nice feature to have and puts the stove's efficiency into territory well ahead of its time.

 

[Backwoods Savage]

Welcome to the forum Tony.

You got the stove from a neighbor. Have you asked the neighbor about the operation of the stove?

Whatever you do, make sure the wood is good and dry. It needs to be split and stacked for a long time before it is ready to burn lest you end up with poor fires and lots of creosote. If your wood was just cut and split this year.....don't burn it. Depending upon what type of wood it is, it should be in the stack a year or more before going into the stove.