Key Stoker Koker 160

Hi
I am new to this forum. Some back ground. I live in an old 3 story building built around 1920, the house was built by my grandfather. It had been a general store on the first floor that is being converted into a single level living area. We are currently living on the 3rd floor. I have been spending about $3500.00 a year in fuel oil using a very old oil burner to heat this old house, I can't tell who the manufacturer is and have had the thermostat set to 62 degrees, we were not warm with out using electric, which added to the heating costs. We are planning on living basically on the first floor and heating it with a coal stoker. We live in Carbon county PA and have access to the coal locally, in August paid $225 for a ton of rice delivered.
I have recently purchased a new koker 160 and had it installed with a direct vent and thermostat. I have a plenum on top that allows me to have 6, 6" flexible ducts to heat the first floor. I fired it up and it appears to be working well but not having and prior experience I am not sure. It seems the convection blower cycles on and off frequently I am wondering if this is normal? Once it turns on it runs for about 1 -2 minuets and will turn off for a longer period of time and then cycle back on. It seems to be heating the room well but not sure if this is normal? It is set to turn on when the internal temp reaches around 160 and the lower limit is set to about 120. I also purchased a magnehelic differential pressure gauge from Dwyer instruments to measure the draft, this is measured at an opening in the ash door. When I first fired it up it was reading -0.2 to -0.4 but with the fire going good it measures at -.05 - .06. Any advice would be helpful and appreciated. Thanks.

Hi Bill, welcome to the forum. I think you might have to throttle the draft down a little, it is stronger than what Keystoker recommends in their manual. Is there a draft control on the direct vent side?

Bill, I have a kiker also.

Once the dayton blower kicks in it should stay on much longer than 1 to 2 minutes. Mine is set for 160/120 also and usually takes about 15 minutes from turning on to turning off when the front of the stove reads 300 degrees if that helps!

2 minutes just does not sound right.

Now when the stove is running at 650 degrees the blower will never turn off!!

First thanks for the help. The manual states that if the draft goes above -.03 adjust barometric damper to open a little wider. I will check this when I get home tonight. Also I am not sure what the temperature is at the stove, I'll need to get a thermometer for that. Does anyone know if this excessive draft cause the convection motor to cycle like this?

from the Koker manual, pg 14:

IF FIRE STAYS LIT, BUT STOVE IS TOO HOT
If convection blower cycles on and off often and produces too much heat, ether the fire bed is too long or timer is running too long. If you reduce coal feed or remove timer pins, do not make radical changes. Reduce coal feed 1 or 2 turns OR remove 1 pin from timer. Then wait several hours before making any more reductions. A sudden radical change may be too much and cause fire to go out.
Once the coal feed and timer are set and fire stays lit, without convection blower running too much, it is usually not necessary to make any more changes.

How large is the hot-coal area in your furnace?

I also wanted to point out that the direct vent does not have a barometric damper. It appears to me that the instructions in their manual on page 3 are for the naturally vented Koker. To change the draft on a direct vent (from the manual)

slide adjusting rod (located in rear of venter) in or out to obtain proper draft. Secure adjustment rod with set screw.

To reduce the draft you slide the rod in (close it) a bit.
My advice here is don't mess with it.


I'm curious about your plenum. Could you post a photo?
I'm assuming you have the plate across the front top edge in place and sealed off. Without this plate in place you'd be quickly blowing all the hot air out of the furnace into the room it's sitting in.
-Len

I have my fan limits set to 110/160. Mine also cycled like yours until I adjusted it. My draft runs right at 0.02 but I don'y have the power vent. When it's burning, how does the fire bed look? When its idling you should have 3" - 4" of ash on the end and when burning hard you should have about 1" of ash on the end. What position is the combustion fan blockoff plate at? It should be at about 1/2 coverage or slightly less.

Thanks for all the helpful information. I did check the draft and it was running at -0.05. I thought that was a bit high so I opened up the adjustment shutter on the draft motor and now the draft has been running at -0.03 - -0.04. I am not sure why but the shutter for the draft adjustment was secured in place by a additional sheet metal screw which had to be removed to allow for adjustment.? The manual states that this may need to be adjusted. The coal bed looks as they describe it in the manual . At idle there is about 1" to 2" of hot coals with small flame. When calling for heat this increases to about 4" -5" of hot burning coal with high flames but there is still about 2" of ash at the end of the bed. I need to get a photos of the plenum, the front opening is covered and the plenum sits on top of the large opening on the top of the stove. Since I was planing on distributing the air throughout the 1st floor there are actually 8, 6" openings for the duct work in the plenum, I am using 7 of these and have the one blocked off because the direct vent is to close to utilize this opening. On Friday evening it got down to around 30 degrees and it was a comfortable 72 degrees on the first floor overnight. Not to bad but it rally wasn't that cold. The convection blower is now running for about 8 minuets before turning off. Could it be possible that I with the large plenum it is moving the heat out of the stoker and that is why the convection blower only runs for this amount of time. Old man winter is coming and i am trying to make sure I maximize the use of the stoker. I will post some picture of my set up as soon as I can.

It could be that the plenum design you have has very little restrictions and is simply cooling the fire box quickly. You could turn the fan limit to 170 or so to make the fan come on later. Really it is just making adjustments until you get what you want. My setup has quite a bit of restriction as I use the original oil furnace blower and blow the house cold air through the Koker and then into the oil furnace and through my A/C A-coil so I don't get optimum air flow. Keep tinkering until you get what you want. You could always turn the feed rate up a little to get a hotter burn if you end up needing it. I doubt you will as these Kokers put out some serious heat!

Thanks for the advice Astro. I am just trying to get a better understanding of how this stoker works. Growing up we always had coal for heating, way back it was a hand fed coal stove but this is my first experience using the direct vent technology. I am curious haw the draft works. I am posting a couple pics of my Koker set up. I don't yet have a pic when it is calling for heat, its been pretty warm lately. I will post the pics as soon as I figure out how to.

i seem to have the opposite problem. (i will give a little background information first) I purchased a used koker this summer from a guy that was moving from the area and worked for a keystoker dealer. I cleaned it up and repainted it. I have a raised ranch house. the living area is about 1100 sqft and i have about 600 sqft of the basement that is insulated and i am currently refinishing. the stove is in the finished part and is at the base of the basement steps. I cut a vent hole in each of the bedrooms which are over the heated part of the basement. i have two 8" holes out the top of the stove, one goes straight up to the living room and the other goes out the wall into the garage and over to the kitchen. I also moved the plate on the front to the right one bolt hole so that there is a little air blowing in the basement. When i turned the stove on it fired up when the thermostat was calling for heat but the blower kept coming on and off even though the stove was at idol. I did some research and found that at idle i had 4-5' of burning coal and the flames were pretty high. i turned the feed rate counterclockwise 5 turns so far and i have about 1 1/2" of burning coal at idle. I also found the blower was set to come on at 150 and off at 100. i reset it to 170 and 130. It is a direct vent and i have the draft set at about -.025. It still seems to be putting out a lot of heat and it was 76 in the house when i woke up this morning. thats a far cry from the 65 that the thermostat is set for. any ideas on what to check? im sure that it wont be as big of an issue when it gets colder but i dont want to roast on warm days.

From pg 14 of the Direct Vent Koker manual:

IF FIRE STAYS LIT, BUT STOVE IS TOO HOT
If convection blower cycles on and off often and produces too much heat, ether the fire bed is too long or timer is running too long. If you reduce coal feed or remove timer pins, do not make radical changes. Reduce coal feed 1 or 2 turns OR remove 1 pin from timer. Then wait several hours before making any more reductions. A sudden radical change may be too much and cause fire to go out.
Once the coal feed and timer are set and fire stays lit, without convection blower running too much, it is usually not necessary to make any more changes.

It sounds to me like you need to be removing some pins in your timer. The thermostat controls the amount of coal being burned when the house is calling for heat. However, when the house is warm and no additional heat is needed, the timer takes over, pushing just enough coal onto the burn plate to keep a fire going. At idle, you should only have a thin band of red coals.
I'll attach a couple of photos for reference:
I hope this is some help to you.
Good luck,
-Len

Thanks Len! I read the manual a few times and must have missed the part about removing pins in the timer. I adjusted the feed rate one turn before i left for work this morning. I will see what it looks like when i get home tonight and go from there. Im not trying to sound stupid but im assuming that i would take one pin from each position? Im wondering if the koker is a little overkill for a small house like mine but for $1200, and it was in nice shape with all new blowers, i couldnt pass it up!

Come January you'll be really happy you got the Koker!

The pins can be arranged in any way that works for you. They don't even have to be in three sets (as they come from the factory). It's whatever consistently keeps your low idle fire going. I've settled on 3 sets of 4 pins. For awhile I ran 2 sets of 4 and 1 set of three but that got a little too close to having the coals burn out at idle.
Now is the best time to play with it, when you have long periods of idling. Once the thermostat starts calling for heat in the house, the timer has very little effect on the fire.
-Len

I went home last night and took one pin from each set on the timer. I let it go for a few hours and i noticed that it wasnt burning as hot but it was still throwing heat. Before i went to bed i took another pin out of each set, leaving me with 3 sets of 4 like yours. When i got up this morning the temp was around my thermostat set point and it still is. I am sure that i will still have to play around with it a little but thank you for pointing me in the right direction! I still have to check it at full burn since i adjusted the feed rate so much.

my koker came from the factory with 3 sets of 4 pins and since i have removed 1 so i have 3 sets of 3 and it seems good for this warmer weather but if the forecast is still saying low 70's i will be shutting down and cleaning it.