My S260 had two puff back/explosions last night; with, the second one being HUGE! The explosion scared the hell out of me, my wife, and my three kids. Going down to the basement after what sounded like two shotgun blasts, I found my boiler room full of soot, smoke, and CO. The explosion (probably the second one...) blew the sight tube cover across the room; and, my type M baro right out of it's receptacle. Luckly I was able to put the type M back together (it was blown out of it's "tee" across the room); and, got it working properly again.
I had a few small puff backs with the S130; but, nothing like this. I realize unburned coal gas volitiles cause this problem; but, how can I prevent this from happening again? A small puff back in one thing; but, this was crazy.
My flue arrangement is exactly like the one depicted in the CoalGun manual page 5. Figure 1. with the horizontal runs, tee connections, and type M baro. Luckly I have 3 to 4 screws and high temperature tape holding every exhaust pipe seam together.
I have excellent draft of 0.04 to 0.06" of water as measured in real-time with my Dwyer Mark II manometer; with, the type M baro keeping draft steady. NOTE: I just cleaned/vacuumed the horizontal run last Monday, 10/10.
Could the root cause of the explosion be the sight tube cover being out of adjustment; i.e. not opening fully after the fan stopped running? BTW: I have the little rotary door "open" allowing 100% air flow to the coal bed. With the S130, this minimized small puff backs I was experiencing. Should the rotary door be kept 100% open; or, do I need to play with this adjustment too?
I've been running/boiling since Saturday 7/30; and, I've probably burned about 3 tons of coal. Do I need to pull the fan assembly and clean out the cyclone funnel and swirl chamber?