Feed Problem With a Keystoker KAA-2

One item on your list I don't see, that could be the problem. Have you cleaned out the coal hopper, all the way down to the bottom, and vacuumed out the hopper and the top of the pusher?? A stray large piece of nut coal, or sliver of wood from the mine is all it takes to restrict the flow of coal to the pusher..

You may have answered this earlier in the thread, if so, I'm sorry for repeating the question..

Did you measure the nylon roller? is it undersize?

Greg L

1975gt750 wrote:first off I want to thank everybody for all the help it is greatly appricated.
boiler has been running flawleely for 3 years
i have been running the same coal for 2 years blaschak rice coal
baro damper has not been touched
running a probe style thermometer
.02 draft
all pipes clean oand operational
grates clean and free of coal sands

was runing fine at 4 turnes out until a week ago
now I am at full stoke and having a hardtime keeping up

the only thing I noticed before I had some probelms was the stoker was making some crunching noise but it has done that before.i thought it was some coal stuck in the push plate

here are some pics of how I have been measureing the push plate
so if I could get some measurment s that would be great

let me know chris

1975gt750,
My stack temp is 240 degrees F while idling using a digital temp probe on a multimeter.
My max stroke when measured with tape measure looks like yours.

yes the wheel was worn I replaced it and when I replaced the wheel I emptied the hopper and checked for large pieces of coal and I was all good. so I don't belive it is a blockage I think something happen to pusher possibly bent but did not look like it when I had it out. I am still waiting on answer from keystoker

Chris I asked before but can you tell us about the lubrication of the combustion blower ? From the look of your flame pictures but it looks like you are running out of air to support combustion. The full fire picture shows a narrow flamefront and yet there is plenty of available fuel pushing against it but unkindled.I am questioning air supply to that grate. Mike

i oiled the motor the other day and it seems to running smoth no abnormal noises. but one thing I noticed is it is hot to the touch. I don't know how hot it should be but then again it runs 24/7 . as for the removal of the grates I did not remove them to clean it I just pulled my blower out and made an attachment for my vaccum and I cleaned it out of the combustion blower hole.
heres a question

if I did not have enough air would it be pushing off un burned coal it looks to me is if the coal is burning out before it makes it to the end of the coal bed?

last time when I shut it down to clean the grates I did run my had over the grate and I did feel air comming up through the holes but I don't have a comparision on how much air I should have.

I'm sure I asked this before, but here goes.. when you describe in the above post that you ran your hand over the grate and felt the air coming out, did you at that time use a small drill bit, or piece of wire to go into each air hole in the grate, to assure that it was open, and not clogged with fines and or ash??

Since I haven't pulled apart your keystoker grate/pusher/roller before, I'm going on experience with other pusher/roller systems.. Did the roller fit into a slot in the pusher? Was this slot still rectangular?? that is , was either the pushing or the retracting side of the slot curved from being bent?? On one model stoker I worked on, the width of this rectangular slot was adjustable, and this adjustment determined the total stroke of the pusher.. If you widened the slot, the pusher block moved less, narrowing increased the pushed distance.. you could narrow the slot down till it was the same width as the diameter of the roller.

Could you bend your pusher to narrow the slot [assuming you have a slotted pusher block?] ?

Another possible,, does your pusher block have an edge that might be instead of a 90* edge, be smoothed over by damp fines, so it now is a rounded or 45* sloped 'edge' that can't catch enough rice coal to shove down the grate?? This would be when the pusher retracts, the hopper tries to gravity feed the open spot on the pusher block, if this spot was plugged with fines, there would be very little coal pushed down the grate..

If your entire mechanism is clean, then the only two items are pusher travel [total travel distance] and air supplied to the fire..

Greg L

hey gregg

after you last post I did go back and check the grate holes I ran a piece of wire hanger through all 150 holes in the grate and all seem to be ok. I be able to see a diffrence in about an hour

as for the stoker roller set up it is pretty simple the wheel goes into a slot and front end of the slot is adjustabe so bigger you make the slot the less push it has. as for the return that is fixed and ther is no adjustment on the return just the push.
when I had the push plate out for nylon wheel removal I did check the opening and the adjuster bar and all seemed good no visual bends unless it is bent so slightly that I could not see with my naked eye. would have to possibly put it on a straight edge to see if it is straight.

as for the pusher bar edge that pushes the coal it was caked up with with fines causing a 45 degree edge instead of a hard 90 degree edge. when I first saw that I thought that was my whole problem. so I scraped it out and re installed the push plate. but know change.

maybe I have a weak combustion blower I really don't know how much air it should be pushing I will have to compare it with my friends boiler

keep the info comming its all good and greatly appreciated

chris

I think the air issue has been exhausted. The pictures show a very shallow burning bed. If it was not getting air he would be pushing unburned coal off the end of the bed. I am surprised at how sensitive my VF3000 is to small changes in the push feed. I only push about 1/4 of an inch, anymore and it is falling into the bucket still burning. So, even though I have a lot of potential stroke, it is the last 1/4 inch that counts. Maybe yours is pulling back fine but is not following through to the final commitment. I believe from reading the posts, that your push is adjustable so adjust the fork a little smaller and finish the push. Maybe it is pushing to far back and the coal is "squirting" back up through the hopper opening. Just xome thoughts.

Kevin

This has been quite the "Brain Teaser" Chris. Everyone has been hitting around the area, but no one has pin pointed the problem(s) yet. Myself, I have NO stoker experience what so ever. Not yet anyhow. Anything more from KEYSTOKER?

keystoker wants me try a motor I guess we will see

chris

well hello everybody. looks like I got it fixed and it was not the motor. after numerouse times of adjustments on the stoker and timming the motor keystoker said it was a bad motor possibly stripped in the gear box. well I installed the new motor and still the same problem. I finally narrowed it down to the push plate adjustments. keystoker states that the four nylon screws on the left side of the push plate are to be screwed all the way in and then the four nylon screws on the right side are to be adjustedjust until there is slight drag on the push plate as it slides down the channel. well if you do that by the insructions it does not work. when the push bar is all the way back there was no play but when the push plate was fully foward on push of coal there was about 3/16 of inch play. so what was happening is as the push plate would come foward pushing coal it would cock in is bore because the channel was not perfectly square from front to back and not give enough push causing all my problems. so the way I rectified the problem was I had to adjust one screw at at time to get all the play out. it was kinda tough because I would adjust the far front scew first and then have to put the push plate in on an angle to side it down to make sure it was tight and then pull the plate out and adjust the next screw and so on until all screws were adjusted. now the push plate is tight from front to back. I don't know if it is normal but if I was building a stoker I think I would make the channel perfectly square so the would not be so many adjustments and the other thing I would have done was to drill a hole in the side of the channel to access the adjustment screws so I would not have to remove the push plate to make side-to-side adjustments. but now I have an extra motor on hand just incase it should fail on a cold winter night.

now up and running like normal plenty of heat
had to turn it down the water was so hot that the tempering valve could not handle it

chris

Glad to here you got it fixed. Good info for Keystoker owners if they run into the same problem. Do you know what Keystoker charges for the pusher motor and did they charge you for it?

Glad it's fixed also! Thanks for posting the solution!

still waiting on a bill from keystoker I think it is about 60.00$