Stoker Settings

Greetings all...it's almost heating time of year here in the coal regions of PA but I'm having trouble with my EFM520 settings that are driving me nuts!! Lately I've be having almost 4-6 outfires per week and I really don't understand why. Before this started I hadn't touched my settings for months and things ran fine...I am still on the same batch of coal as well. I checked draft and seem to be ok and even cleaned the pipe to the chimney of fly ash just in case.

I am currently set at 5 teeth 4.5 air with 3.5 minutes per half hour. At these settings my feed pipe stays cool. I tried 4/4 for feed/air but that made the pipe hot. I have my aquastat set at a spread of 140 and 210 to keep a significant range for summer running. One thing I've noticed is that no matter what I run at the high end around 200 degrees. I've read other post that said with those settings expect to water to get rarely above 170. I pretty much always run at 200. I tried running the timer shorter and the feeds lower but the feed pipe either gets hot or I have outfires I think due to the stoker not running enough.

I would welcome any suggestions to help get my settings in line. I'm not sure if I should increase my feed/air to get more burn for my timer run or increase the timer to get more burn when it runs. I worry that more timer will keep me in the dead band too long and the timer won't run.

It's not unusual for the feed pipe to get hot, it's just when the pipe's paint starts burning off that it's too hot. You might want to try 4/4 again and a little less time. Say 2 minutes per half hour, or a little higher. Is the cleanout cover fully shut with the lever?

stokerman....I'll give the 4/4 a try again....I wasn't sure how hot was too hot....I'll also knock back the time again....I relit the stoker again tonight but first I tapped out most of the hot water to bring the temp down to 100 before I started and I'm still back up to 200 degrees...the stoker is in it's own small room but that amazes me that it's back up to 200 already....it's only been like 60 here lately and 40 at night. The clean out level does seem to go in all the way when I finish with it....I will look down in the ash bin tonight to see if it's truly closing all the way.

Check the aquastat low setting to ensure it's 140. Let the unit fire up and the motor should shut down when the temperature gauge says 140, give or take a few degrees. If not, the aquastat is out of calibration. If it overshoots the 140 significantly, after it was recalibrated, the aquastat is bad.

I checked the lever and the cleanout is closing completely when I release the lever. I changed my settings to 4/4 and 2.5 on the timer and no outfire last night. Although it wasn't long since the relight and it usually takes a full day until it slowly works itself out.

The temperature was still at the higher range this morning as well. I will check the aquastat setting this morning. Is there a way to recalibrate it if it's off. I believe I do remember having it set to 140 and it shutting off more at 150/155 before but I just chalked that up to the 10 degree differential.

If you have the manual settings on an L8124, when the gauge says 140, turn the knob until it clicks and shuts off the blower motor. Verify the new setting for a few cycles to see how close it is to 140. You'll have to bump it back up to 160 soon anyway.

The differential works in the opposite direction, a function to protect the hot water coil. It controls the circulator.

The aquastat bulb may not be properly sensing the water temperature in the aquastat well..

When you have an outfire, is the coal completelty burnt up? so you have ashes all the way to the bottom of the pot?? or is the pot full of fresh coal, and the layer of ash very thin?

When you said you checked your draft and 'it seemed ok' , how did you check the draft?? Do you have a barometric damper installed in the flue pipe??

If you have too much draft, it could be pulling too much air through the coal when it is not stoking.. this could increase the heat from the fire, and keep the water temps high..

Use a manometer to check and set the barometric damper to the corrrect setting,, about .04 to .06" wc if I remember correctly.

Somehow the fire is making too much heat at idle. The above scenario is all I can think of.

Hope this helps

Greg L

Making the adjustments that stoker-man suggested seems to be doing the trick. I went back to 4feed/4air and now have my timer set at 2min. My pipe is warm but isn't paint peeling off hot. Any time I check the fire there is a decent ring of glowing coals followed by the ash ring I believe is desired. My temps run from 170-200 usually so I don't think I'm hitting the high limit cutout. At the very end of a timer cycle before things die down a bit I think I even have the famous "dark spot" in the center.

So far this has been working for almost 2 weeks now so I have my fingers crossed. I'm hoping that I only have to adjust the aquastat when it comes to switching over to home heating.

The ash ring should be about 1 1/2 to 2 inches wide.

I'll bet your timer is turning off and then the temp is rising another 20-30 degrees after the timer and blower have shut down, which is normal.