Harman auger tube burn hole repair

[Tim_M]

A few months ago I noticed my 23 year old Invincible T had developed a small hole at the front of the auger tube, just below the end of the auger. This seems to be a not that uncommon issue, at least with some of the older Harmans. I think it was probably due to a bad hopper gasket that allowed air into the tube and fire at the opening to the burn pot. Over the next several weeks the hole seemed to be getting slightly larger, so I figured I'd better try to do something about it.

The thought of dismantling the entire stove in order to remove the feeder weldment and get the hole welded was not at all appealing, especially since I was only half way through the winter and it would mean the stove would be down for a few weeks. So I decided to try a simpler approach. I removed the burnpot, and inserted a bolt down through the hole after grinding the head down to ensure adequate clearance for the auger. On the end of the bolt I installed a small piece of gasket material, a flat washer and a lock washer, before securing it all in place with a nut.

It has been over a month since the repair and my stove has been working great. Sealing the hole, in combination with a new hopper gasket has resulted in the flame moving out to the front of the burn pot, with no sign of fire in the auger tube. I've attached a picture of the hole before and after the repair.

 

[fedtime]

Nice job. I'll bet that repair would last for many more years without any difficulty.

What is the plan? Are you going to repair/replace the tube in the off season?

 

[Tim_M]

I don't think replacing the tube is an option, since the feeder weldment for this stove has been discontinued for a few years now. I'm hoping that my repair will last for a while. If not maybe I can come up with another fix.

 

[TStark]

Well executed Tim!

Yes, would be a shame to replace the entire weldment, even if still available.
Just info for posterity for other 'T' owners searching, no need to junk a stove.
Tim has some run time on his solution now, and the weldment takes to Tig welding very well to fill the hole, removal and replacement is the catch.
My welder wanted 20 bucks, i gave him 40.

During operation, one should be able to dig and find unburned pellets at the exit of the auger. If the burn is happening in the auger tube a hopper air leak exist that needs remedy else the hole will develop and grow till stove is unusable.