Anyone have a Harman with the auto draft?

I have a Vogelzang Norseman furnace and am working on designing and installing a thermostatically controlled draft. I don't want a draft fan. I like the looks of the Harman auto draft. I have a few ?'s regarding the harman draft and if anyone has a Harman with the auto draft and wouldn't mind answering a few ?'s or maybe taking a few pictures for me, let me know. I would appreciate it!

Ben

I don't have a Harman, but, are you referring to a bi-metal coil w/ chain controlling a hinged door flap?

I removed one like that from a 1970's Riteway Wood/Coal Stove recently.

No actually the Harman auto draft is electric. It has a 24 volt wall thermostat that controls a geared motor that opens and closes the draft with the need for heat.
Ben

I would look into adapting a zone valve used on hot air furnaces.

Another way would be to use the power head from an hydronic system. The Taco power head on my system only has about 1/8 inch throw, but is powerful. With simple lever of 4 times leverage you could get 1/2 inch throw which should be enough. The Honeywell power head might have more throw. The power heads are readily available as a replacement part. Of course you would need the transformer and thermostat.

franco b, I believe that is pretty much what the Harman draft consists of. I know its a geared motor with a spring return. Power = motor turns opens draft. No Power = spring returns motor and closes draft. I would like to know what brand and model number of geared motor the harman draft uses and I would also like to look at the draft mechanism as I would like to build something like it.

Ben

I have a Harman with that exact system. I also purchased a spare (complete, motor,spring,gears etc). Tonight I don't have model# etc. but will look it up tomorrow. Not very expensive and works fine. The reason I have a spare, mine quit, and I ordered a new one before I gave it a good look over. Because it was not sealed small bits of coal and ash had jammed gears. I cleaned, SEALED and put back in service.

Robby

Robby, That would be great if you could get me that information. Could I maybe talk you into taking a few pictures of your draft setup?

Thanks!
Ben

You bet.
Sorry, got tied up today, will take pictures, get numbers, etc. tomorrow and post early as I can as I am in "Mountain" time zone. Most of you guys are in bed before I read posts.

Robby

Hey Robby, where U from? I'm also in Mountain time zone. I live in the southeastern corner of Montana. Also, thank you for your willingness to take pictures, etc. It is appreciated!

Ben

Small world. I am from Priddis, Alberta, SW of Calgary way up high in the hills. 4400 ft to be exact. Your not very far away.

OK, the (Damper Actuator and link drive) is ERIE make and part #0453H0038KB00.
110V 50Hz and 120V 60Hz 6.5 watt. I think I paid about $120 for complete unit.

The electronic controls switch it on or off. When on the motor just keeps pushing (through gears) on wheel which hold damper door open. When power off spring rolls moter in reverse. I think if you keep grit out of the mechanism they last a very long time. I did not seal mine and over a year or so enough ash,grit got in to jam it. Cleaned and put back on. That was last fall.

I am trying to figure out how to inset a picture, will work on that. In the mean time take a look at HArmon site
http://www.harmanstoves.com/products/de ... f=BLRSF360

You can download the manual and there are pictures of draft door etc.

Robby

I'm back.

I re-read your first post. It would be real simple to have thermostat control relay and relay supply power to damper motor. Does furnace have controls that prevent it from getting too hot?

Years ago I owned a house (cabin really) in B.C. that had a wood furnace and the draft worked exactly like that. Can't remember if it was identical, but very similar.

If you need any more pictures or info from this setup, just let me know.

Robby

Looks like this would work.

http://www.pexsupply.com/Honeywell-M847A1080-24V-2-Position-Damper-Actuator-w-arm-linkage

McGiever, thanks for the link. I do believe that it will work for what I am doing. Thanks!

Robby, thanks for the pictures! I think this setup will work very well for my stove. I was wondering if you could take a few measurements for me if you wouldn't mind. The measurements I would like are:
1. The size of the draft opening.
2. The size of the idle air inlet holes.
3. Approximately how far from the bottom of the inlet does the "actuator lug" contact the door. From what I can see in the picture it looks about half way. Correct me if I'm wrong.
Also, from what I see in the pictures, the door hinges at the top, correct? Is there a spring that pulls the door closed or is the inlet cut at a bit of an angle so that good ole gravity keeps it closed? Also, approximately how far does the door open when the thermostat calls for heat? I'm guessing it isn't much as large as the door is? Also, is there a screen or something in the inlet that keeps small pieces of coal from rolling out and jamming the draft door open?
I hate to bother you any more, but would you mind taking a close up picture of the hinge area.
I really appreciate your willingness to answer my questions and go through the work of taking pictures. I really appreciate it! I am going to owe you big time!
Thanks!
Ben