Why is the stack temperature so high?

RayWohlfarth

I felt the heat from the flue while 5 feet away. After inserting my analyzer, the stack temperature read 600 degrees F. What causes high flue gas temperature?

https://www.youtube.com/watch?v=DjmwZp86wTo

EBEBRATT-Ed

Over firing, dirty boiler, inefficient burner with too much excess air, air leaks into boiler through leaking door gaskets, between section etc (if an old neg draft boiler)

RayWohlfarth

@EBEBRATT-Ed Yes sir I ran out of room Thanks

Alan (California Radiant) Forbes

Nicely done, Ray. I'd say the water-side scale issue is the most difficult to determine - and fix - but none of them are easy.

jumper

Only a theory. In the fifties HHW boilers were derived from solid fuel steam boilers. They sat on a firebox although they came with an oil burner. Later converted to gas. No engineering work.

So heat transfer stunk. Only in seventies after energy crisis did anyone consider efficiency.

Fire_Man

Thanks for sharing this story. Draft requirements are often overlooked. When compounded by set-up errors and service/maintenance neglect; it is a wonder equipment holds up as long as it does. At the same time, life-span is dramatically shortened, heating costs are much higher than they should be, and unnecessary risk is created that will surely lead to costly repairs & replacement, or worse — a catastrophic fire.

RayWohlfarth

@Alan (California Radiant) Forbes I agree. Scale is nearly impossible to access . They used to acid clean boilers but haven't seen that in a while.

@Fire_Man Youre right draft is often overlooked when troubleshooting boilers.