Damper question FEC 100

I've read comments from Eddy that stated if you restrict the exhaust it will cause heat to build up in the pellet hopper, which in turn will cause the pellets to fall apart and jamb the auger.

quote:

Originally posted by BlueCloud:
Is there any reason to NOT install a damper on the FEC 100 exhaust stack/

Logically it's a good question, but from what I've seen, I've not seen a good way to do it.

You'll change the airflow and the cases of the fire going out go up about 1000%.

I've seen more than enough cases of people just adding flues (not dampers) and that change alone is enough to affect the airflow.

Remember the damper would hinder oxygen from getting in as well as smoke getting out.

But like we say, try it and let us know. Just be ready for the above problem.

Air pressure is something I agree with. But.... since airflow is /pushed forced outward thru the stack, maybe the oxygen flows into the unit through the grease drain?? A 45 degree restiction certainly shouldn't hurt the unit you think? I got the part to mod the stack, but I'm 50/50 on doing it.

One thing I know I've heard Stuart talk about is the air pressure issue. Sometimes restricting it actually creates something of a backflow/air pressure into the smoker, so the smoke stays.

The fan alone isn't enough oxygen. It just "fans" the flames". The fire gets it's oxygen from inside also. That's why I think the flue issue tends to cause airflow problems. The pressure changes in a way the oxygen can't get in from the vent and the fire snuffs out.

If you want to try it, give it a try, just keep an eye on the variables and maybe it will work.

Have you considered restricting the flow of air getting to the fan? The bottom part of the side panel on the older FEC's had several small holes drilled into it and that was how the fan pulled in air. CS has since switched to a large hole over the fan covered with a wire grate. Maybe covering part of the hole to restrict air might help, but then again it might cause more issues, I don't know.

I've got one of the older side panels and I've considered switching it out on my newer FEC. I've mentioned in other posts that my '11 model FEC100 blows ash all over inside the cabinet and the fan seems to run alot more than with my '08 model. The '11 model also uses about twice as many pellets as my '08 does. I'll switch out the side panels and if I see any difference I'll report back.

First of all- DISCLAIMER:
The opinion presented doesn't come from an Electrical, Mechanical, or Environmental Engineering Discipline as I don't have one. My opinion is from expierence with the unit and similar devices...

I Don't think you should to impede the exhaust of the FEC at all. The unit was designed to be very energy efficient. (So much as that It doesn't waste enough energy to pollute the product with unspent fuel (Smoke).

If you try to block the exhaust you create pressure. Pressure creats more friction and thus more heat. Pressure like water and electricity seeks the lowest point of resistance. thus pressure exhausted back thru the auger and into the hopper and thus hopper fire or expanded pellets and a jammed hopper and then fire out.

The fan will produce enough oxygen to keep the fire going to produce more pressure and thus more heat and the cooker becomes a small combustion chamber if exhaust is restricted.

These cookers aren't temprature controlled by airflow they are temprature controlled via software. This means that airflow must remain somewhat a constant and the software controls the fuel availability rather than conventionl smokers control the oxygen availability rather than fuel.

There are three sides to the triangle that creates fire. 1)Fuel 2)Heat 3)Oxygen Unlike being a fireman (Fast Eddy)to eliminate heat by controlling fuel and oxygen, we are doing the opposite in our project to cook meat.

We must maintain two sides of the Triangle (Fuel & Oxygen) to create a constant heat.

Cookshack does a very efficient job of maintaing heat and the by-product of that for me is that they do it so efficientlty that I get to sleep while it maintains both Fuel and Oxygen thru software so I don't have to constantly tend to the fire.

Like I said earlier, they do it so efficiently that the pollution that we so desire to settle on our products is insufficient to our acquired taste. How do we fix it?

Well two ways.

The First: Add something like I did that will create a lesser efficient consumption of fuel by placing a chunk of wood off to the side of the fire pot that will receive ample heat and oxygen to ignite yet not enough to efficiently consume so much of the fuel that it makes a polluted smoke that flavors our products in a more traditional manner.

The second which is using a two stage method of operating the cooker at a sub-standard temprature that causes the fuel to be in-efficiently be consumed and thus producing more smoke at the expense of a grealy lengthened cook time which may not be condusive to safe cooking times for meats like poultry and fish.

Since the FEC100 has a NSF rating neither would be a factory option from a product liability stand point.

I have pondered with the idea of installing a varible speed controller on the fan where I could get the fire up to 250 and then adjust the fan to a lower speed to where it would hold temp but produce less burning efficiency and thus producing more smoke. But wait!
when my FEC does get up to temp the fan does slow down. I must trust the folks at cookshack that they have done the tests that proved that the fan is slowed down to a threshold that if ran any slower the temp wouldn't hold and thus the auger would ramp up and smother a oxygen starved fire and extenguish the fire and thus a fire out situation.

I will say that smoke doesn't naturally run from the firepot straight to the exhaust on the side because once again the laws of physics takes place and heat rises, and as it rises it creates convection and then hits the roof of the FEC bounces down thru the racks and then is drawn out the exhaust as its BTU's are consumed by the meat and its heat tranferred and our food is cooked!

I know I rambled but I think it is one hell of a cooker that produces smoke as a secondary benefit. and I've learned to get the smoke I need while maintaing the main principles of the reason I bought the thing which were,

1) Cook a lot of meat at once
2) Do it in an efficient manner so I didn't have to stay up all night managing the cooker
3) Take one obstacle out of the maze of winning a BBQ Contest!

Well done! (no pun intended). Thanks

I have no technical background ,just a basic cook.I have been around Eddy,cooking, for a bunch of years and on the phone with questions ,as well.

Everytime someone would would ask a question,The answer was usually" because that is the way it works consistently".

I really never give any of these mods any thought,as I usually try to stay focused on the cooking and the finished product.

I've been fortunate to be around Eddy and the cookers for over a decade and have cooked on custom designed Fe s and FE 100s ,before they were FEC s.

Eddy would try everything other cooks and firemen could dream up and spent many efforts at process of elimination.

Eddy tried to get it down to the KISS principle,where cooks could leave these out all year in storms,be hauled and beaten up all across the country,have virtually no problems and win consistently.

We have been thru a half dozen different ones for comps,vending,cater,home cooking and have virtually no problems that were not "operator error".
We have been to comps that looked like FEC trade shows/conventions and the cooks had no problems.

Not sure whether market forced changes dictate mods,but these are just a couple of my observations.

I have placed 90 degree turn downs on both of my FEC100's. And I feel this allows a little more smoke to stay in the cooker. The smoke must fill to about 1 1/2" below the bottom of the outlet tube. No extra back pressure just a lowering of the smoke level.


RandyE

Randy, don't have a FEC 100, but the reason you're getting a little more smoke in the cooker is that you are adding back pressure with the 90 deg elbows. Anytime you add/or deviate from a straight airstream/flow you are going to create some back pressure, the reason you're seeing more smoke. In your case it seems to be working well.

BD
PG1000
FEC120

I would agree that anytime you deviate from a straight line, you would increase back pressure. But given a 5" 90 on a 5' outlet, and given the low rate of air which travels through the pipe.
I think it would be nearly impossible to measure the difference.
Raising or lowering the outlet height in the cooking chamber would not change the pressure created by the fan.

RandyE

quote:

Originally quoted by RandyE:
Raising or lowering the outlet height in the cooking chamber would not change the pressure created by the fan.

I believe it would. Heat rises, so if the outlet was higher it would create more of a natural draft, like what you need in a flue pipe. I'm guessing this is why they are recommending a 3' section of pipe with a flue cap on it. That would get it at just above the smoker box top, hence creating more draw(less back pressure). I've seen Eddy's setup and that is how he does his.

With all that said, I do just like you are doing Randy...oh well! Never have had a problem yet.

Cal, are you saying that a 3' section creates a slight draft and that this is more desirable?

I'm thinking it would then move the smoke out faster.

I've used a 3' section with a vent cap on mine and used it with just a 90* elbow. I really can't say one had better smoke flavor than the other.

I guess there is two ways of looking at this question. If your trying to trap more smoke aren't you in turn burning less pellets, which will produce less smoke? Are we gaining anything by doing that?

I've taken Rodney's(Pellet Envy) cooking class, where he cooked on a Jambo offset. I'm thinking to myself that 2 stage cooking with the FEC will produce the same product he is producing out of the Jambo. This is just my opinion thou, but I really don't want the smoke to be the main feature of my meat.

I think the 3' piece of pipe has more to do with flame outs and the cause...pressure!

Great discussion...and I am off the ledge...I will leave my setup as is; that is...without installing a damper. Returning it back to home depot. Wonder if cookshack ever toyed with the idea of a dual feed pellet system... with one ramp that feeds pellets to a firebox that would just incrementally smolder pellets without a fan i.e an added smoke switch setting like the traeger has? Oh well,, any way I see there is some science to what makes this thing perform. Like it was said by Tom, Fast Eddy made it simple for a reason.

Hey Cal, maybe the 3' piece creates the slight draft, that would compensate for the added small pressure of a cap. Or am I thinking to much?