StokerDon wrote: ↑Thu. Sep. 27, 2018 6:18 pm
This type of pipe has features that are completely unnecessary for a coal stoker boiler. The air gap is there to give more clearance to combustibles, this is great if you have 1000 degree flue gasses (wood). Your GJ will rarely ever get above 400. Also, the air gap will likely cool the inside of the chimney which will in turn really hurt the idle draft.
It also states that the second wall is galvanized steel, not stainless. Once fly ash and moisture get onto the galvanized, it won't last long.
If this product costs more than their double wall insulated pipe, I would definitely not use it. The double wall is stainless inside and out and works very well.
-Don
Hi Don,
Since the pipe is capped at the top and bottom, I guess I was kind of thinking that the air gap between the outer pipe and the second pipe wall would provide dead air space creating some insulating effect.
I did see that about the second wall being galvanized (actually because I got a chance to look at the pipe first hand in the store and saw that it was galvanized). But I don't understand why this would be exposed to fly ash as it is insulated from the inside 8 inch flue pipe which would be carrying the gasses and ash.
Having said all the above I see your point about the double wall. And yes! The price of the triple wall 8 inch and 10 inch pipe is crazy expensive making the block chimney look even more favorable. In fact the only way i could probably afford the larger diameter pipe would be find some used in good condition.
