Koker losing manometer reading when blower turns on

I just picked up a one year old keystone koker 160. (Looked like it was brand new) I attached to a recently built chimney. When I fired it up I started getting a lot of fumes and had to turn it off. I received and hooked up a dwyer 25 manometer and it read between .02 and .03. I have it ducting into about 15 feet of 8 inch diamater metal duct pipe. I put a thermoter in the duct pipe about 5 feet from furnace. As it started heating up I noticed the duct thermometer went up 210 degrees then the stove turned on. The duct thermoter dropped to about 140 while fan was on. The big problem that I see is that when the blower turned on the manometer went to + .05 (Positive pressure) and I could feel and smell the air comming out of the barametric damper which was being forced closed due to pressure. Any information would be creatly apprecieated.

Chimney is plugged?

Describe your chimney, it sounds like it is clogged. the combustion fan in the stove should not be able to create a positive pressure in the chimney
UNLESS it is blocked or clogged..
Do you have a source of fresh 'make=up' air to replace the air going up the chimney and down the ducts?? Sometimes a room is too tight for a
chimney t be able to draw enough air .

But it sure sounds like the chimney is at least partially blocked.

Greg L

Check your stove pipes for flyash build up

sorry but I am unclear about 1 thing..
you said when the " blower" comes on... draft will go positive

... do you mean the combustion blower (i would assume)
... or do you mean convection blower... that sends the heated air through your duct..??

... positive pressure in the chimney from the combustion blower would definitely indicate restriction in the flu... you said you have a baro installed... any chance you have a manual damper also?
... but if you mean the convection blower ( when that comes on) is creating positive pressure in the chimney... that's an entirely different story.
... my first bet would be chimney is restricted.
... but my confusion lies here:
you're getting a good draft when you started up... and you are getting 210 degree duct temperatures
... so I'm assuming your combustion blower is already running?

Noticed you said it was a newly built chimney, still check it for no obstructions. Do not burn without Carbon Monoxide Detectors installed.

Also, you might try restricting the air inlet of the fan...less air in = less air out. The manometer will read the changes as you adjust the restrictor at air inlet.

Thank you for such a quick response. I apologize for the confusion on which blower. The blower that causes the manometer to jump is the one that come on to blow the hot air through the ductwork. I was just speaking to a freind who works on coal stoves every day and he believes I have a crack or a hole somewhere in the firebox or heat exchanger. That would account for the high temps in my ductwork (Hot gasses leaking into duct) and for the pressure when the fan turns on. I plan on removing blower and top plate to inspect for something obvious. I probably will also contact Keystoker but I am not sure if they will be able to assist for I am not the original purchaser. I am going to try to attach 2 pics to give you a visual. Again that you for all you help.

As Greg LS Farm indicated, your house may be too tight,

Crack a window in the room where the stove is located and see if the manometer changes.

If your house is too tight, when that big old convection fan comes on, it is sucking air from wherever it can. If the room is too tight, it is actually pulling or creating a backflow in the flue pipe. This used to happen at my old shop when I had all the doors and windows closed and turned on my spraybooth exhaust fan. It would actually cause a back flow from the oil burner. Cracking a window would solve the problem. This is usually called "make up air."



Rick

hmm

I didnt want to jump to conclusions...but it def sounds like the fire box is compromised. That would explain positive pressure when it comes on


The simplest way to check this would be to DISCONNECT the duct from the top of the stove
...this would allow the air in the room to "free wheel"...as you wont be evacuating it.
"spillage" should then be prevented...if that is the problem.
...unfortunately this would entail you firing it up again

Rick is onto the problem.

Is yor cold air return drawing off the basement floor? From the pictures you posted it looks like that is the case. If so and your basement is tight, it could pull on the chimney for a source of air to make up for the vacuum created when the circulating blower pulls air out of the basement. If this is the case, hook up a cold air duct work line to the first floor. You should also consider running a 4" combustion air supply from the outside to the combustion air shutter/motor. Both of these systems, a cold air return and outside combustion air, should stop the back flow thru the chimney. There ar several threads on this forum regarding running combustion air lines to a Koker.

Im gonna lean the other way on this one a bit...
koker 160 has a 1500 cfm convection blower
..thats a TON of air !
Not that a single 8 " duct will allow that much through it...but alot of air just the same.
.again- remove the supply duct or restrict inlet
...if the basement is even fairly tight...that size blower could create neg. pressure in the basement..(reading positive on your guage)

...but fumes immediately on start up (with adequate draft ) indicates something else (imo)

...

I am tending to agree with rick36 on this one.

Lets keep the checking simple. Coal stove operation and coal burning is not an exotic action. Do not assume anything. Verify it visually.

1. I didn't see anything in the photo's showing where the return air is coming from. If that big distribution fan is sucking from the same room the stove is in chances are excellent that it is just pulling the fumes right out of the stove and into the fan ducting. If that is the case then when the blower starts and sucks all that air, it's going to get it from somewhere. What better place than back-drafting down a wide open chimney? Open a window WIDE OPEN in the stove area and try it again. If the firebox pressure stays negative you found the problem. Not enough makeup air in the stove area.

The Koker needs to be tied in to the return air system and it needs lots of makeup air. See the threads in this forum for cold air return for Koker or Koker return air.

2. Verify visually that the chimney is COMPLETELY open from top to bottom.

3. Verify visually that the flue pipe is COMPLETELY open from stove to chimney.


IMHO start with the most obvious and work to the obscure.

Rev. Larry

The Koker is a furnace, not a stove. The 1536 CFM blower is a big part of that difference. It needs to be drawing air from your return duct, not your basement. Rick, Rev Larry, Greg and VigII are right, you are currently pulling air down your chimney through your damper.
You also need to get a much larger hot air connection to your duct work to get all the heat the blower is trying to wash off the furnace. That single small line is going to offer too much resistance to good hot air flow.
The Koker will keep you very warm when you get it hooked up right.

CoaLen wrote:The Koker is a furnace, not a stove. The 1536 CFM blower is a big part of that difference. It needs to be drawing air from your return duct, not your basement. Rick, Rev Larry, Greg and VigII are right, you are currently pulling air down your chimney through your damper.
You also need to get a much larger hot air connection to your duct work to get all the heat the blower is trying to wash off the furnace. That single small line is going to offer too much resistance to good hot air flow.
The Koker will keep you very warm when you get it hooked up right.

I agree with the above. Not quite sure ,but when the combustion blower is running without the convection blower look to see witch way the baro flap is going then turn the convection blower on and see if the baro flap changes direction.Or put a candle in front of the baro to see any changes in air flow.