Plate Boiler Baffle Cover?

I need a little help understanding one aspect of my Yellow Flame boiler. The Yellow Flame is a plate boiler which means the hot gasses go up, then down under a plate, then up over a plate, the down the back side and out the flue. This action scrubs the heat off of the hot gasses and into the water flowing through the plates.

It's the last part that is confusing to me, down the back and out the flue. The base of my boiler is totaly open. There is no sectioned off part in the back. meaning gasses can go up through the base into the flue as well as through the plates. So my question is; Should I make something to block that bottom path to the flue off?

I hope you all can understand what I mean. Here are some photos.
The last one you can see how close this opening is to the flue outlet.

-Don

So, I'm driving home from work today, I'm thinking about making a metal plate to fit over this opening in the bottom of my boiler. I know I don't have any steel plate, I have some heavy sheet metal, no, that won't last long in there, I do have that piece of metal I got with the Yellow Flame that I couldn't figure,, out,,, where it,,,,,,, THAT'S IT!!!

I got home, went down in the basement, found that piece of metal, held it up to the opening,,, perfect! I used some of my leftover pipe to hold it up. My draft went from .02 to .03.
After looking at these photos, it looks like that plate sits on TOP of those 2 tabs, not under. I'm glad I take pictures! I don't think I would have caught that while looking inside the base!

-Don

Nice discovery there SD.

The yellow flame I had was so abused when we moved into the house it was in. I couldn't tell what was what. Someone had cut that last baffle plate that did the last up and down so that when you looked into the base you could look right into the flue outlet. I guess it corroded and fell out or got chewed out by metal eating termites as I could see ragged spots of bad metal where it used to be in the base.

I thought about welding a plate back in there and decided Naw.....all I gain is a couple of % points of efficiency for a lot of effort by keeping the hot gas inside a little longer. Not worth the cost of the plate or burning myself up inside that tiny space. I had bigger problems with warped grates, cracked side burner plates, boiler controls working backwards, high limit not working, leaks, leaks and more leaks that I had to fix. Coal from Lenig's was cheap and only 15 minutes down the road.

Increasing draft for the stoker is not that critical and in fact could work against you as long as you got decent draft to start with. Now your chimney is gonna suck the hot gasses out of the boiler quicker and by installing the baffle plate are you now hurting your efficiency because your sucking the hot stuff out quicker and it's not hanging around longer? Just askin....

You may want to check your flue outlet temp with the plate in place and without the plate in place and judge accordingly.

Rev. Larry
New Beginning Church
Ashland Pa.