Looking for the best Coal stoker for my applicatiton.

pret wrote:I guess I'll need an RC type. Can I pick these up at the local hardware store? Pret.

The RC is what I have. Most contractor supply houses (if they sell smoke pipe, stoves, boilers, furnaces, etc) sell them for about $15-20 depending on the size.

pret wrote:Thanks coaledsweat. The links are helpful - I guess I'll need an RC type. Can I pick these up at the local hardware store? Pret.

You want a 5 inch sized RC. Just bought a new one a month ago, $21.23 at my wholesaler. You should run 5 inch flue pipe from the S-130 to the chimney thimble. The big box home improvement stores don't sell 5 inch flue pipe. Try a hardware store that sells wood or coal stoves. It can be difficult to find. Seal all joints well.

Yanche wrote:

pret wrote:Thanks coaledsweat. The links are helpful - I guess I'll need an RC type. Can I pick these up at the local hardware store? Pret.

You want a 5 inch sized RC. Just bought a new one a month ago, $21.23 at my wholesaler. You should run 5 inch flue pipe from the S-130 to the chimney thimble. The big box home improvement stores don't sell 5 inch flue pipe. Try a hardware store that sells wood or coal stoves. It can be difficult to find. Seal all joints well.

The new AHS manual suggests that the draft control be the same size as the flue pipe (not the size of the stove pipe from the boiler)--if the flue pipe is 6" then use a 6" draft control. It further says that if the flue pipe is square to use the round equivalent--defined by example for a 14" square flue to be 14" round.

[/quote="bob"]The new AHS manual suggests that the draft control be the same size as the flue pipe (not the size of the stove pipe from the boiler)--if the flue pipe is 6" then use a 6" draft control. It further says that if the flue pipe is square to use the round equivalent--defined by example for a 14" square flue to be 14" round.[/quote]

That sounds just a little silly if you ask me. Where would one get a 14" draft control and the ungodly adapter to mate it to a 5" stovepipe?

http://www.fieldcontrols.com/pdfs/04592700.pdf

There are different design considerations on the size and location of barometric dampers. Where the damper is located and it's size depends on the fuel type and the number of appliances of the single fuel type drafting to a single chimney flue. With coal not only does the appliance exhaust combustion gases it also contains fly ash. This fly ash does not make it to the top of your chimney. It's heavier than the flue gases and will fall out. Where it falls out is determined by the flue gas velocity. Ideally you would want all of the ash to be transported to the chimney stack. That way the change in gas velocity occurs where the smaller diameter stove pipe meets the chimney thimble and the ash falls down to the chimney base clean out. Think of it this way, it's kind of a shop vacuum cleaner. Only with the AHS coalgun it's a blower. The stove pipe (technically called a convector) blows combustion gases and ash to the inlet to the chimney stack. There the larger chimney size causes the velocity to slow and the ash falls out.

So far so good. But it's not that simple. When the AHS coalgun combustion blower is not running natural draft takes over. It's sucking the now idling coal fire combustion gases and heat out of the boiler. Not good especially on a windy day. You need to regulate the amount of "suck" on the boiler. That's what the barometric damper does. It shunts a portion of the draft to pull air out of the room not the boiler. The amount is regulated by the barometric damper flapper door. Usually by some kind of movable weight. Properly set it still drafts enough to suck the combustion gases out of the boiler but not so much that it causes the coal fire burn more. One way to determine the proper setting is the measure the draft "over the fire" with a tube draft gauge temporarily inserted over the fire. With the AHS coalgun the flapper door on the front of the boiler opens allowing room air to enter. This changes the path of the air flow in the boiler. Air is no longer flowing through the coal bed, it's flowing over the top of the burning coal. Just what you want. A boiler that idles well when heat is NOT needed.

The ability of a barometric damper to regulate flow is dependent on it's physical size. Technically you want the flapper door to be operating in the flat part of it's curve. What size damper needed is based on the chimney stack size. Large diameter chimney, large barometric damper. For AHS coalgun boilers it should be located at the chimney stack thimble. The Fields 5 inch RC barometric damper is specified for 5 or 6 inch "convectors". Use 5 inch stove pipe so that the velocity is kept high and the ash is conveyed to the chimney stack. Make sure there is a slight uphill to the chimney thimble. You don't want a place for combustion gases to collect. This will contribute to the "puff back" condition described in the Bureau of Mines Report. If you have a very, very large diameter chimney (12 x 12, 12 x 16, etc.) you will need a larger sized barometric damper.

For other than AHS coalgun installations understand the principles I've described; size and locate the barometric damper appropriately. For example if it's a natural draft appliance you might want the barometric damper near the stove so that you are aways "sucking" the fly ash to the chimney stack.

Thanks fellas... the excitement and anticipation is building. Thanks for the clarification and the helpful information. Take care. Pret

Complete Heat wrote:The best "Class A" pipe, in my opinion, is made by Security. It offers a 30 year warranty, even if you are burning coal. For the single wall 316TI liners I too like the Ventinox (made by Protech Industries), but read the warranty. It is a lifetime warranty except if you burn coal. Then the warranty drops down to 10 years. Homesaver brand 316TI Ultra-Pro is an outstanding liner as well, and is a lifetime warranty, even if you are burning coal.

Mike

Which brand do you use when you install the Alaska Power Vent? Do you like their Power Vent? Any customers have problems with it?

I don't know which Alaska venter you are refering but you want the one which mounts thru the wall ( swg makes them for alaska) not the one which mounts directly to the stove. The forementioned allows you to use a barometric damper and in my opinion is a must to prevent overdraft which not only sends your precious heat out the vent but can cause a hopper fire especially in the alaska stoves.Also the one that mounts on the stove(Alaska vent) positively pressurizes the flue pipe which has to be sliconed at the joints. Also it requires much more maintanence inreguards to cleaning out the pipe.

The hanging metal disk over the inspection port on the AA130 is designed to allow draft to bypass the fire. Doesn't the AHS have this feature anymore?

Yes the AHS has the same inspection port that the AA and Eshland boilers have. However, if the draft is too strong, it acts just like the combustion fan, it sucks the inspection port closed and causes the boiler to overfire, and have temperature overshoots. This is why a barometric damper is recommended for instalations where a strong draft is evident.

I can see the big oval inspection port on my AA260 sway from the draft moving around it when the wind is real gusty and the baro damper is working hard. Without a baro damper even my short chimney could pull the inspection port closed on a windy day.

Greg L