110 Boiler Feed Screw Settings

Flyer5 · Post by **Flyer5** » Wed. Oct. 10, 2012 4:39 pm

kstills wrote:I'm glad to see this thread, because I have a similar type problem.

I just took delivery on a new order of coal, and I'm starting to get a ash dam form at the middle/front of the grate. It idles fine, but when I get a heat call and the stoker goes full out, the fresh coal builds up behind the damn and starts to spill over the sides of the grate. The real negative effect is that the fire is not as hot (it burns more like wood then coal) and it takes forever to hit the LL on the aquastat to restart the circulator.

My setting hasnt changed (I put tape on the screw to make sure it was always exactly the same spot) but I'm thinking I'll have to change it to run slower.

Did you have the grate out for any reason. I have seen that when the grate is not fully seated in the front properly.

kstills · Post by **kstills** » Thu. Oct. 11, 2012 8:26 am

Flyer5 wrote:
kstills wrote:I'm glad to see this thread, because I have a similar type problem.

I just took delivery on a new order of coal, and I'm starting to get a ash dam form at the middle/front of the grate. It idles fine, but when I get a heat call and the stoker goes full out, the fresh coal builds up behind the damn and starts to spill over the sides of the grate. The real negative effect is that the fire is not as hot (it burns more like wood then coal) and it takes forever to hit the LL on the aquastat to restart the circulator.

My setting hasnt changed (I put tape on the screw to make sure it was always exactly the same spot) but I'm thinking I'll have to change it to run slower.
Did you have the grate out for any reason. I have seen that when the grate is not fully seated in the front properly.

I haven't had the grate out, but I did spin the boiler around when I put the new piping in. I'll review all this Saturday and get back to the board.

kstills · Post by **kstills** » Thu. Oct. 11, 2012 10:04 am

Update:

I spoke to the guy who delivers my coal, and although he said it was from the same mine, he found that he's had to back out his feed screw to get the same burn as he had with last years coal. Seems it's burning hotter, longer so it needs to be adjusted to compensate.

These things are more like hobbys than appliances.

jpen1 · Post by **jpen1** » Thu. Oct. 11, 2012 11:26 pm

Having to chnge the max feed rate with different batches of coal does happen sometimes. Up until this last load I just got I have never toouched the feed screw otherthan to change to my summer setttings. This batch I have now I had to take out 2 full turns on the feed screw. It burns longer and the flames are much higher and my draft settings haven't changed. I have never seen ash like this either. It looks almost like pulverized lime with almost no texture at all and not even a hint of bone in it.

kstills · Post by **kstills** » Fri. Oct. 12, 2012 9:25 am

Well, last nite I backed out two turns on the feed screw, and my fire was out this morning......(grumble grumble grumble....)

Matthaus · Post by **Matthaus** » Fri. Oct. 12, 2012 12:38 pm

kstills wrote:Well, last nite I backed out two turns on the feed screw, and my fire was out this morning......(grumble grumble grumble....)

A word to the wise "NEVER I mean NEVER adjust the feed screw without checking/adjusting the idle settings per the manual"
The trick to these boilers is try not to make it any more complicated than it is, setting the high fire and idle should only need to be done once, if you adjust the screw while calling for heat and then disconnect the burn circuit wire for adjusting the idle fire you should have "set it and forget it" relatively quickly. Also wait .5 hour after any adjustment to make sure things are OK before proceeding to the next step.
Keep the faith.

kstills · Post by **kstills** » Mon. Oct. 15, 2012 10:08 am

UPdate on the 'slag dams' (great term, btw

)

I didn't get to do the cleanout this weekend, however during routine maintanence I emptied the ash pan and the ash is actually coming off the grate in blocks. What I suspect is happening is that the dam forms, packs tight and then is finally pushed off the end of the grate from the force of the new coal building up behind it.

The boiler answered several calls for heat over the weekend (Friday and Sat nites were cool enough here for the t stat to kick on) so technically it is operating. But I will need to figure out why these dams are forming.

Post by **Rob R.** » Mon. Oct. 15, 2012 10:44 am

It sounds like your fire is creating clinkers.

jpen1 · Post by **jpen1** » Mon. Oct. 15, 2012 5:43 pm

You are creating clinkers most likely because your new coal has a lower ash fusion temp. and has a higher iron content.

kstills · Post by **kstills** » Tue. Oct. 16, 2012 1:04 pm

Is there a way to avoid creating clinkers, or is this simply a necessary evil with burning coal?

McGiever · Post by **McGiever** » Tue. Oct. 16, 2012 9:03 pm

kstills wrote:Is there a way to avoid creating clinkers, or is this simply a necessary evil with burning coal?

Possibly cut back a little on the air can reduce tendency to hit ash fusion temperature and making a clinker.

Matthaus · Post by **Matthaus** » Thu. Oct. 18, 2012 9:38 pm

The combustion fan on your boiler runs at a fixed speed when the boiler is calling for heat, so to reduce air slightly take a small piece of aluminum tape and cover a small fraction of the air inlet on the combustion fan.

As has already been stated, your clinker issue is the result of high iron content coal, the good news is that it burns hotter, the bad is that the clinkers can cause issues. If you are running rice, you can mix in some buck to help break up the clinkers.

In the final analysis the clinkers don't hurt anything unless you are getting chunks large enough to pull the fire off the grate and cause an out fire.

Hang in there!

kstills · Post by **kstills** » Mon. Oct. 22, 2012 12:52 pm

The biggest issue I have atm is that I'm getting some un-burnt coal coming off the grate. What does burn burns to a white ash, but because I'm getting those slag dams some of the coal isn't burning all the way.

My coal dealer has buck, so I'll pick up a few bags and see what happens when I mix it into the next hopper load. Thanks for all the advice.

KLook · Post by **KLook** » Mon. Oct. 22, 2012 2:01 pm

You may always have some unburned coal. My experience was that every bag of Kimmel I opened was an adventure. Rocks, coal the size of hockey pucks in rice, sticks, leaves, rope) That was why I made a screen in my hopper. However, I burned Reading and Blaschak also and I could tell the difference in unburned amount of coal because I spread them in my driveway and after a good rain the black rocks laid on the top. Sometimes it was a solid sheet of black and other times it was just a few sprinkled in. Varied within the pallets of the same brand.

Kevin

plumber · Post by **plumber** » Mon. Dec. 17, 2012 5:39 pm

Does this ash look normal? I can't seem to balance between hot coal falling off the grate and having 2" of ash at the front.