Retrofit Hitzer Thermostat to Harman

Today I put a thermostatic air intake on my Harman Mark I. I bought stock parts from Hitzer, same as on the Hitzer 30-95, which is roughly the same size stove. I considered parts from a U.S. Stove Wonderwood 2931. I think they would have done as well or better, but I would have had to build my own thermostat housing.

First picture is the air intake tube. My brother welded some ears on it so I could bolt it on. Second picture is my 35-year-old Craftsman 3/8 variable speed drill resting after work. Several forum members recommended that little white Lenox hole saw. It’s tougher than it looks. Third picture is the work of the hole saw. Three one-inch holes for a total intake area of slightly over two square inches if my math is correct. I used Vaseline petroleum jelly from the medicine cabinet to lube the saw and the drill bits. I think the saw is good for another hundred holes. Fourth picture is from inside the ash pit, looking out the new holes. Next picture is the air intake bolted in place, then two pictures of the finished product. At some point I will spray the intake door flat black so it will blend in better. I sealed around the edges of the intake tube with the red high-temperature silicone gasket maker, inside the tube because on the outside the ears are in the way, and the red color would look funny. Now I have to wait patiently for 24 hours for the silicone to cure, before I can find out if the whole thing works.

Oops! Last two pics didn't make it on the first posting.

Looks like you did a great job to me. Good luck!

Nice job.

How scarey was that, drilling into a perfectly good stove? It reminded me of the time I installed my own SunRoof in my brand new 1981 toyota. Measure Twice, then Measure Twice again, Then finally take the plunge with the sawzall

Looks good I suspect it will work well for you.

DVC500_at_last wrote:How scarey was that, drilling into a perfectly good stove? It reminded me of the time I installed my own SunRoof in my brand new 1981 toyota.

Well, if it doesn't work out I can always stick chewing gum in the holes and put it back to normal. But going at your own new Toyota with a sawzall? That's brave! Couldn't you find someone else's to practice on first?

Not centered on the side because...

Not centered on the side because (a) the interior baffle is toward the back, and I didn't want to run afoul of it when drilling for the thermostat, and (b) I don't think it matters much -- the Hitzers let their air in on a back corner.

The thermostat housing also is not centered above the intake, because the chain attaches to the bi-metal spring close to one side of the housing. I tried to position it so the chain would run vertically.

In retrospect I could have mounted the thermostat closer to the top, without running out of chain. That would change the pull angle slightly. But I'll try it like this and see how it works. It gets fired up later today.

Mr. Murphy would see to it that the screw hole would line up perfectly with the baffle edge or weld bead!
Agree that the location is no big deal.
You may get the ash buildup from that side instead of the front.
Plenty of room to go around the ash pan.
Now are you going to radius those holes to get maximum airflow?

Nice looking job! I do believe it will work just fine. Some day, should you ever get the stove near a welder & torch, you can weld around the inlet, then cut the holes out completely. On second thought, I'd leave it the way it is. This way you have the option of putting the set-up on a different stove.

Capecoaler, I don't know what it means to "radius the holes", so I guess I won't, or if I do it will be by accident and I won't know I have done it. I think I will have enough airflow now, slightly more than 2 square inches. I did some crude measurements and estimates on my spin draft, and that's more intake area than I ever ran the stove at except for right after loading new coal. As you mentioned, I am curious to see whether the burn pattern and ash buildup change noticeably.

oliver, my brother volunteered to weld the air intake, but it didn't seem wise to do it in the living room with the lace curtains four feet away, and I didn't want to unhook everything to haul it out to the garage. If I decide to undo it, this will be easier.

[quote="rberq"]Capecoaler, I don't know what it means to "radius the holes", so I guess I won't, or if I do it will be by accident and I won't know I have done it.

I think Capecoaler must have some engine modification background. Radius the holes would be the equivalent of porting and polishing the intake ports on an engine head and intake manifold for better air flow. I suspect he is saying it "tounge in cheek".

Hot Rod Harman!
Hitzman..
Har...
Hitman!

Looks good Bob, what was the price of the thermostat?