Outdoor Furnace Rookie Needs Help!

[Xylophile]

Hello All!

I have recently put a locally fabricated outdoor wood furnace into service.  The firebox opening is 4' by 4', 5' deep.  it is surrounded by a thousand gallon water jacket.  This furnace will be used to heat a commercial dry kiln (25-30,000bf).Well seasoned pallets are the main fuel.  Can anyone offer helpful hints regarding the use of this contraption?  It is my first experience with an OWF!

The door is already seen as a weak spot.  It bows a little when at higher temperatures, allowing smoke to escape around the top and bottom.  The door gasket "fell off" soon after we started using the furnace.  It was re-glued, but didnt last long.

Many Thanks,

Walter

[beenthere]

I wonder why the smoke doesn't go up the chimney. Seems there would be a draft (incoming air) around the door openings where not sealed. Any pictures?

[Corley5]

Try putting an extension on the chimney to make it draw better

[Neil_B]

What brand is it?
I would be in contact with the company to check it out. May be just a matter of replacing the door. Under warranty of course.
Could be also that you are trying to start too much of a fire to get the water temp up. Try a smaller more gradual fire if this is the first time fire. Then once the temp is up, you can fill the furnace to the hilt.

[Xylophile]

Sorry, Beenthere!  No photos yet.  I'm a rookie with the digital camera, too.

Corley 5:  The 10" chimney is 22' off the ground.  It starts 6' off the ground.  Trouble is,the furnace is backed up to an industrial building that is about 24' high.  We have intended to add a couple sections to get the chimney above the roofline.  But other things demanding attention ...

Neil_B:  The furnace was manufactured locally, has no brand!  This is not the first fire for this stove.  I've been breaking it in for three, maybe four weeks.  Everything I'm doing is a learning process right now!!

[OneWithWood]

I would definately keep in contact with the builder to resolve the door gasket problem.
I burned pallets in my wood fired boiler (WFD not ot be confused with WMD).  The biggest problem I had was the disposal of all the nails!   What do you plan to do with the nails and staples?

[Chet]

I would defiantly get the door fixed. You will not be able to control furnace temps, because of draft air entering around the door. This can be especially dangerous if you are running a pressurized system.

[Mark M]

If I remember correctly the chimney should be 3 feet above anything within 10 feet. That is part of your problem, but like Chet says the door leak is top priority.

[beenthere]

Seems it would be very difficult to control a fire fueled with just pallets. They are dry, like kindling, lots of air space, and likely burn very fast (borderline to an explosion).  Fast burn, very hot (ie warped door), and slow to warm up the water jacket.  1000 gallon water jacket seems like a lot, as I heat my house with a wood-fired hot water unit that has just a 9 gallon water jacket (true, you are trying to heat a large kiln, but my unit is equivalent to a 100,000 BTU furnace, and your 1000 gallons of water is 100+ times my 9 gallons). The boiler ends are not 'contained' by water, and the door end has a cast-iron door that if not careful, can get very hot. My system works great, but I don't think flash fires in it would do any good (slow to heat the water and too hot on the parts of the unit that are not water).  

I think considering another wood fuel source to supplement the pallets would be worthwhile to successful burning. Better draft as mentioned also important. How often is the chimney cleaned, or do you clean it with a roaring fire?  Still, smoke out the door cracks is indicative of problems with draft.

Other questions I would have is how much surface area between the heat chamber and water jacket do you have to transfer the wood heat to the water, and how many BTU equivalent do you expect from this unit?