OMG, NOW we're getting somewhere!!
Quotes that help me tremendously from the very recent previous posts:
Yes, you need the blue flames before closing the load door completely. The blue flames prove that the combustible gases are burning instead of building up inside the fire box.
If I get in a situation where I don't see the blue flames, I will push back some of the fresh coal in one corner of the firebox, so that some of the red hot coals are exposed. I haven't had any puffbacks with this method.
you will never get a puff back if you load in a few layers giving each 10 minutes or so to catch.
It is very important to never ever run air through the coal bed full blast after shaking down.
Running air full blast is what causes puff backs.
The blue flames you see when you open the door, or puff is not because you gave it air but because you gave it less air through the coal bed by bypassing it with the door open.
I just got up out of bed to post this because I was revisiting what happened. In my initial post, I stated that I didn't see blue flames. But I DO REMEMBER now that when I didn't see the blue flames after closing the load/glass door, I opened it up and there they were! I closed it again and they disappeared. I then opened it a 3rd time and they came back. So every time I closed the door, they disappeared and every time I opened it, they came back. Seeing them, I closed the door and went up to the garage.
franco's information explains what is happening there. But how do I know when it's safe to close the door after seeing the blue flames? I saw blue flames and then closed the door and got the explosion. would it be a rule of thumb that it's safe only when you see blue flames while the load door is open and you CONTINUE to see them steadily after closing it? ...because my blue flames went out when closing the door.
That is probably the most important thing I need to know at this point, so any input on it is welcomed!
I have learned everything else I think I need to know otherwise:
* Leave a red glowing corner when loading;
* Never close the load door without seeing blue flames;
* If you have a low fire with very little coal, add smaller amounts, not one huge load;
* Puffbacks are more likely to occur on a warm day;
* Running fresh air at full blast will cause a puffback since the draft is too strong, not allowing the gasses to ignite.
...so I feel like if I get an answer to the above question, I'll feel like this is wrapped up. Thanks again everyone!!
P.S. franco, putting ashes on the fire is a great idea for me since I don't have sand or dirt readily available. I suppose I could grab the spade in the garage and start digging in an emergency, but since I have 2 ash pans, I always have one full of cold ashes from a few days before (allowing them to cool down before discarding them).