Harman Stoker Expert?

LsFarm · Post by **LsFarm** » Sun. Jul. 27, 2008 9:37 am

Terry, don't you have a continous running combustion fan on your stoker?? Or is that a Matthaus modification??? I'm surprised that you had a hopper fire, what was your chimney draft while it was burning?? Do you have a full time Manometer???

Greg L

coalkirk · Post by **coalkirk** » Sun. Jul. 27, 2008 11:09 am

No, the Harman combustion fan cycles off when in pilot mode. That occurs when the boiler reaches setpoint. Then the Harman controller turns on the combustion fan and feed motor based on customer settings on two timers. My fire occured during pilot mode when the fan was off. Draft while running was .04. On idle, it drops to .02-.01. Matt has a coaltrol which I believe runs the fan continuously but at variable speed I think. I only picked up 4 buckets of buck. I'll mix it in with the rice.

coalmeister · Post by **coalmeister** » Sun. Jul. 27, 2008 11:26 pm

coalkirk wrote:Well yesterday was an interesting day. Started off with a left over part. Got that resolved. Then my feed adjustment was unexplicably limited. Got that resolved. I came to my office to post what I found and how I fixed it. When I went back down to check the boiler, I had a hopper fire. No visible flames but plenty of smoke coming out of the hopper. I only had a pound or so of buck in the hopper luckily so it didn't take too long to empty it and get things under control. So my experimenting with buck is over. Coalberner warned my that might happen if my draft wasn't real strong. The boiler had reached its setpoint and gone into idle mode. In idle mode the combustion fan shuts off. The fire followed the feed path right back to the hopper. This happened in about 10 minutes. So I know during cold weather conditions my draft would be stronger, there are times when the weather gets more moderate and my draft would be less. So I'm glad I tested in summer conditons because it dramatically showed my what happens with buck under poor draft conditions. I know Matt had burned buck in his Harman stoker sucessfully but he was running the combustion fan continuosly and using a coal-trol.
Gee that was fun.

Maybe run rice in the Summer and buck in the winter?

coal berner · Post by **coal berner** » Mon. Jul. 28, 2008 4:04 am

coalkirk wrote:No, the Harman combustion fan cycles off when in pilot mode. That occurs when the boiler reaches setpoint. Then the Harman controller turns on the combustion fan and feed motor based on customer settings on two timers. My fire occured during pilot mode when the fan was off. Draft while running was .04. On idle, it drops to .02-.01. Matt has a coaltrol which I believe runs the fan continuously but at variable speed I think. I only picked up 4 buckets of buck. I'll mix it in with the rice.

Hey Terry glade you got it I Told you you might have some Fun with it

The continuously Running Fan does 3 things
it helps keep the draft up Plus it helps keep the coal burning in idol mode When you don't have A Fan running all the time
your draft will lower and you will see a lot of unburnt coal in your ash That because there is not enough air to burn it
all the way Plus with out a continously fan you will have more of a chance of having a outfire Thats way Keystoker started
to put Fans on there stoker boiler People where having Problems with outfire's in the summer time The draft would drop
and the fire would go out with the fan running all the time you will not have that Problem Plus you will burn the coal
completely to ash instead of having unburnt coal in the ash tub Terry PM Matt he has the info on How to hook your
fan up so it runs all the time Then you will beable to burn buck with out having a Hopper fire in the summertime

Bulldogr6 · Post by **Bulldogr6** » Mon. Jul. 28, 2008 4:36 pm

Seeing you got your feeder travel issue kicked could you take a measurement of the opening after you closed it up for me?

I ask because my magnum seems to have the same symptom now

. As I said in my earlier post I have my hopper off for a clean and lube session and when I plug in the motor I only get travel of the first four or five marks as well. Maybe this happens if something jambs or binds up?

coalkirk · Post by **coalkirk** » Mon. Jul. 28, 2008 8:37 pm

Sure, I'll measure the yoke for you. I was conservative when I "adjusted with a hammer." I'll probably take it back out and close the opening alittle more. Mine stilll doesn't travel the whole scale. It's got to be from some foreign object getting caught in the feed.

Bulldogr6 · Post by **Bulldogr6** » Mon. Jul. 28, 2008 9:17 pm

Upon further inspection I found that mine is a good as it can get. If I close up the yolk any more than a 1/8 or so on the return when it moves up it will bind on the shaft of the motor. Be sure to watch out for this yourself if you plan on closing it up more. Turns out the indicator holes are just a guide and differ from unit to unit, you will not travel the absolute whole scale.

Freddy · Post by **Freddy** » Tue. Jul. 29, 2008 5:25 am

Uh-ohhh....good going! Oh, rats.... yippeee! Oh crud.....

Geepers, what a ping-pong story! It slapped you back and forth, took you to duece and then stomped you dead. It was kind of fun to be able to fix a problem with only a hammer. Gotta love mechanical things that are like that! But, alas, it does look like it's rice for you.