I am having problem keeping the temp on a horizontal smoker after made mods

[sermormo]

Hello fellows,

I am new on the forum however I would like to ask you help to solve several problems I am having to keep the temperature of my smoker steady after made the mods for a horizontal smoker. I will appreciate any help you can provide me.

First let me provide you some information about the smoke. The smoker is an Omaha offset smoker, it is pretty similar to the Brinkmann offset smoker, here there are some pictures of it.

DSC04968.JPG

• sermormo
• Feb 20, 2013

Now, as you already know, this kind of smoker needs a set of modification in order they work as they should work. So, after research on the web, I proceed to make the following modification base on this website, http://amazingribs.com/tips_and_technique/offset_smokers.html/ .

These are the results after I applied the mods:

1. Reverse flow system: As you can see on the picture, I installed a heavy steel duct like the ones built into the large commercial offset smokers and moved the chimney to the side by the firebox. However, I am not sure if I am using the right width for the heavy steel duct, I am feeling the steel is very width therefore it is very difficult to warm it with the heat that is coming from the firebox. Please note that I also have added a deflector as part of the modification.

This is the deflector that I installed on the cooking chamber.

DSC04967.JPG

• sermormo
• Feb 20, 2013

This the heavy steel duct.

DSC04971.JPG

• sermormo
• Feb 20, 2013

And this is the final set up with the deflector and steel duct together.

DSC04973.JPG

• sermormo
• Feb 20, 2013

2. Make a charcoal basket and add a bottom grate to the firebox. On this modification, I am not sure what is the best position to sit the charcoals on the basket? Right now, when I place the charcoals on the basket, the charcoal just sat 5 inches below to the cooking chamber's duct. I am guessing this could affect the amount of heat that cooking chamber is receiving from firebox.

Please take a look of the following pictures and explanations

This is the charcoal basket on the firebox.

DSC04977.JPG

• sermormo
• Feb 20, 2013

Please note that charcols are sitteing 5" above the opening  cooking chamber conduct.

DSC04978.JPG

• sermormo
• Feb 20, 2013

Please note the charcoals are not sat on the botton of the firebox, there is an space betweeen the botton onf the firebox and the charcoals

DSC04979.JPG

• sermormo
• Feb 20, 2013

3. Extend the chimney downward and add thermometers: These mods are working as expected.

Finally, this are my questions and problems

1. After put a lot briquets on the  charcoal basket, temperature does not increase more than 150 F.

2. The charcols turn off after around 60 min. I am feeling this is because there is not enougth oxigen on the firebox or the vent are not big enought to feed the charcoals.  Please take a look of the vent coming with the smoker

DSC04981.JPG

• sermormo
• Feb 20, 2013

Finally, I would like to thanks in advance for any help you can provideme to fix this smoker..

 

[brdprey]

just my opinion the angle and depth that  your rollin at seems really low. but , just to ask a few dumb questions.

when smoking you are smoking with the exhaust fully open and adjusting the inlet?

what type of fuel are you using?

 

[sermormo]

Hi brdprey,1. I smoke with both the exhaust and the vents fully open.2. I use charcoal fuel and every other time i put some apple wood or seasson wood. thanks for you reply.

 

[bruno994]

If the charcoal keeps going out and you can't get temps above 150, you are not getting near enough air to the fire.  As brdprey stated, keep the exhaust and intakes fully open until you are up to temp, then cut back on the intake to control your temps.  Work on getting more air to your fire first, maybe cracking the firebox door or ash pan open a bit, see if this works for you.  Really sounds like your starving your fire of food, O2.

 

[pgsmoker64]

I agree with Bruno.  You are not getting enough air to feed the fire.

You may need to increase the size of your air vent, or do like Bruno said and crack open the ash pan.  I used to do that on my CG w/ SFB to help get the temps up.

Bill

 

[sermormo]

Thanks for the advices, This weekend I am going to try removing the ash pan in order to see if there is a temperature increase on the cooking chamber. During the test, I will leave the exhaust fully open.Quick question, do you think it would be a good idea to include some bricks on the bottom of the cooking chamber and include a small water pan to increase the temperature on the cooking chamber?ThanksSermormo

 

[daveomak]

DSC04968.JPG

• sermormo
• Feb 20, 2013

This is the deflector that I installed on the cooking chamber.

The white points pointing down are obstruction the heat flow to the

Cook Chamber...  Can they be removed ??

DSC04967.JPG

• sermormo
• Feb 20, 2013

This the heavy steel duct.

DSC04971.JPG

• sermormo
• Feb 20, 2013

And this is the final set up with the deflector and steel duct together.

Does the "steel duct" leave room at the right end for air and 

heat flow ??  It looks as though it extends to the end of the cook chamber ??

That could be how I'm looking at it.... the "steel duct" needs to end

about 6" before the end of the cook chamber.....

DSC04973.JPG

• sermormo
• Feb 20, 2013

This is the charcoal basket on the firebox.

Nice basket.....

DSC04977.JPG

• sermormo
• Feb 20, 2013

Please note that charcols are sitteing 5" above the opening  cooking chamber conduct.

DSC04978.JPG

• sermormo
• Feb 20, 2013

Please note the charcoals are not sat on the botton of the firebox, there is an space betweeen the botton onf the firebox and the charcoals

Looking at the middle of the picture....  below the opening to the Cook Chamber.....  

It looks as though there is an opening between the Cook Chamber and the Fire Box,

where the FB bolts to the CC...  Can air get in through that space ??

DSC04979.JPG

• sermormo
• Feb 20, 2013

Very nice vent set up.....   the bottom vent should be open to provide air to the fire

and heat the fire.....   The top vent should be opened to allow for the heat to travel through

the CC without add heat to the fire.....   with experience, you will get a "feel" for how

those two vents can work together.....

DSC04981.JPG

• sermormo
• Feb 20, 2013

Finally, I would like to thanks in advance for any help you can provideme to fix this smoker..

When operating this smoker, you should be putting about 10-15#'s of charcoal in the basket.....  then adding about 12 lit briquettes to it....  That is called the minion method for using briquettes......   then adjusting the fire with the bottom air inlet and adjusting the air through the smoker with the upper air inlet .....   and the exhaust stack (chimney), on the cook chamber, should be fully open at all times during the smoking process....  A water pan will keep your smoker colder than not using it.....  I don't recommend using it....   

Dave

 

[brdprey]

after looking hard at it, think aobut doing some of the following.

i would raise your baffle just a bit , looks like its riding low and maybe restricting it a bit

on your charcoal basket. you only use the lower vent for the air in not the top one. i see it looks like there are two inlets by having the bottom one open only your drawing air into your fire, feeding it sort of say.

and since were picking it apart. maybe reduce the size of your charcoal basket by a inch or two max in height, and raise the floor in what you remove. maybe get a couple pieces of rebar under the bottom to raise the basket that one inch. keep us informed. look forward to seeing how it does.

 

[bruno994]

Bricks and a water pan would only help to hold and level out heat, not increase.  Figure out the temp problem first, then work on leveling the temps out with a heat sink of some sort (sand, water or bricks). 

Dave also brings up a great point, possibly using too little fuel?  Of course that doesn't answer the reason the fire goes out, thats just lack of air flow. 

I agree with Dave on cutting a bit of length off the RF plate might allow for more air flow as well.  Could be restricting and choking down air flow at the end of the plate.

 

[sermormo]

The white points pointing down are obstruction the heat flow to the Cook Chamber... Can they be removed ??

Maybe this picture don’t allow you to see the real form of the opening to the CC. The white points you are talking about is the space where the air is entering to the CC. however you are right on some way, there is a piece of stteal obstructing the heat flow. I am going to remove it. Take a look of the following image and let know if it make sense to you.

Image002.jpg

• sermormo
• Feb 21, 2013

Does the "steel duct" leave room at the right end for air and heat flow ?? It looks as though it extends to the end of the cook chamber ??

That could be how I'm looking at it.... the "steel duct" needs to end about 6" before the end of the cook chamber.....

Yes, I left about  5" of space from the RF right ending to the right end of the CC. Do you think it will be a good idea to left more space there?

Looking at the middle of the picture.... below the opening to the Cook Chamber.....It looks as though there is an opening between the Cook Chamber and the Fire Box,where the FB bolts to the CC... Can air get in through that space ??

The opening below CC you talk about is a space between the right end of the ash pan and the right ending of the FB however, it don’t goes out of the FC . However, Do you think, it would be a good idea to close it or put something over there to avoid heat goes on there?

Very nice vent set up..... the bottom vent should be open to provide air to the fire and heat the fire..... The top vent should be opened to allow for the heat to travel through the CC without add heat to the fire..... with experience, you will get a "feel" for how those two vents can work together.....

I left both fully open in order to get more oxygen into the FB.

When operating this smoker, you should be putting about 10-15#'s of charcoal in the basket..... then adding about 12 lit briquettes to it.... That is called the minion method for using briquettes...... then adjusting the fire with the bottom air inlet and adjusting the air through the smoker with the upper air inlet ..... and the exhaust stack (chimney), on the cook chamber, should be fully open at all times during the smoking process.... A water pan will keep your smoker colder than not using it..... I don't recommend using it....

 Definitely this is something I will try during the weekend, once it is done I will come back with the test results. Thanks Dave, I really appreciate all you thought on this.

after looking hard at it, think about doing some of the following.

1. i would raise your baffle just a bit , looks like its riding low and maybe restricting it a bit on your charcoal basket.

2. you only use the lower vent for the air in not the top one. i see it looks like there are two inlets by having the bottom one open only your drawing air into your fire, feeding it sort of say. and since were picking it apart.

3. maybe reduce the size of your charcoal basket by a inch or two max in height, and raise the floor in what you remove. maybe get a couple pieces of rebar under the bottom to raise the basket that one inch.

4. keep us informed. look forward to seeing how it does.

I will keep you post for sure. Thank you

I am 100% agreed with you. I feel that If I sit the charcoals a little close of the CC opening, the heat flow can easily reach the CC. However I would like to try all not complex configuration before to try those than demand more effort. Therefore, this will be on my long term "TODO" list as well as the raise the baffle. Thanks for you feel back

Bricks and a water pan would only help to hold and level out heat, not increase. Figure out the temp problem first, then work on leveling the temps out with a heat sink of some sort (sand, water or bricks).

 Okay, I will try this on the near future test case scenarios. Just once I start to talk about keep temp steady.

I agree with Dave on cutting a bit of length off the RF plate might allow for more air flow as well. Could be restricting and choking down air flow at the end of the plate.

 What I am going to do, is take a better picture of the RF and measure the space between its ending and the right ending of the CC. With the accurate measure, it will be easier for you to know if I am having the right space on this configuration

BTW, do you think it would be a good idea to do some holes to RF? I saw this approach in other smokers?

Now, based on your feel back, this a list of your recommendations:

Short term(Just Configuration)

1. (Weekend test)Use the Minion method to lit the charcoals.

2. (Improvement)Measure the space between the ending of the RF and the right ending of CC.

3. (Weekend test)Increase the amount of oxygen get into FC by removing the ash pan or left both vent opened.

4. (Future)Use brick and water pan to keep the temp steady not to increase it.

Long term(Complex modifications)

1. Raise a little charcoal basket a couple of inches and reduce the size of the charcoal basket. The idea is to get a better heat flow to the CC.

2. If required cut the RF. The main idea is allow more heat flow get into CC.

Finally I would like to thanks all your advices and feel back. Thank you very much

PS. I am not native English speaker so please apologize me for any typo  I could write on this post

Sergio

 

[daveomak]

Very nice vent set up..... the bottom vent should be open to provide air to the fire and heat the fire..... The top vent should be opened to allow for the heat to travel through the CC without add heat to the fire..... with experience, you will get a "feel" for how those two vents can work together.....

I left both fully open in order to get more oxygen into the FB.

Close the top vent partially so more air to the firebox and a little air flowing through the smoker....    try that...    Dave

 

[sermormo]

Got it Dave. I will make some testing tomorrow morning. Thanks

 

[sermormo]

Hello fellows,

I just finished the first test case scenario based on you advices, please take a look of the results:

Test case scenario description:

1. Place on the smoker's fire box 16 pieces of lid charcoals on 16 unlid pieces of unlid charcols.

2. Set the air button inlet completly open and the upper inlet partially open(25% open.)

3. Close smoker doors.

Temperature tracking

 

Schedule	Temperature(F)	Notes
07:35 a.m.	0	I placed 16 pieces of lid charcoals on 16 pieces unlit charcoal into the smoker's firebox
08:05 a.m.	100	None
08:19 a.m.	110	None
08:35 a.m.	130	Smoke starts to goes out from exhaust
09:05 a.m.	150	None
09:35 a.m.	150	None
10:05 a.m.	125	None
10:35 a.m.	0	None

Images of the test

DSC04983.JPG

• sermormo
• Feb 23, 2013

DSC04984.JPG

• sermormo
• Feb 23, 2013

DSC04985.JPG

• sermormo
• Feb 23, 2013

DSC04987.JPG

• sermormo
• Feb 23, 2013

DSC04989.JPG

• sermormo
• Feb 23, 2013

Results:

Unfortunately, the temperature did not increased more than 150 F.

I would appreciate your feedback and thoughts about it. Again Thanks

Sergio

 

[cliffcarter]

IMHO you need to raise the height of the deflector and the steel you are using to create the reverse flow, I believe they are restricting temps because they are too low so they are restricting the air flow from the fire to the end of the pit, raising them will allow more unrestricted air flow which will give you higher temps. Heat wants to rise, you are forcing it down and it doesn't want to go there.

It also appears that the piece that you are using as the reverse flow plate is too long, that will also effect airflow. Try cutting off 4 to 6 inches of length on that piece.

 

[daveomak]

ser, evening....   The amount of charcoal you put in the basket was not enough to cook a steak, let alone heat up that entire steel smoker.... Put enough charcoal in the basket to fill it half full.... have a tin can with both ends cut out in the basket before you put the charcoal in it....  fill the tin can with lit coals....   pull the can out and watch that smoker heat up......   There is a lot of cold steel to warm up...   Next test, check the temperature of the exhaust stack and the cooking chamber...  I think most of your heat is bypassing the Cook Chamber and going out the stack ....  Like cliff mentioned, the RF plate looks a little low..... It should be side to side at the height of the opening to the firebox and from the FB to about the 5" you have it from the end....  If there are gaps in the RF plate before it gets to the end of the cook chamber, fill them with aluminum foil so the heat travels full length of the RF plate...

 

[cliffcarter]

IMHO you need to raise the height of the deflector and the steel you are using to create the reverse flow, I believe they are restricting temps because they are too low so they are restricting the air flow from the fire to the end of the pit, raising them will allow more unrestricted air flow which will give you higher temps. Heat wants to rise, you are forcing it down and it doesn't want to go there.

It also appears that the piece that you are using as the reverse flow plate is too long, that will also effect airflow. Try cutting off 4 to 6 inches of length on that piece.

ser, evening....   The amount of charcoal you put in the basket was not enough to cook a steak, let alone heat up that entire steel smoker.... Put enough charcoal in the basket to fill it half full.... have a tin can with both ends cut out in the basket before you put the charcoal in it....  fill the tin can with lit coals....   pull the can out and watch that smoker heat up......   There is a lot of cold steel to warm up...   Next test, check the temperature of the exhaust stack and the cooking chamber...  I think most of your heat is bypassing the Cook Chamber and going out the stack ....  Like cliff mentioned, the RF plate looks a little low..... It should be side to side at the height of the opening to the firebox and from the FB to about the 5" you have it from the end....  If there are gaps in the RF plate before it gets to the end of the cook chamber, fill them with aluminum foil so the heat travels full length of the RF plate...

OK so I don't remember seeing the pics when I posted before so you should disregard my comments for now and fill that charcoal basket per Dave Omak's last post and see if that does the trick.

 

[sermormo]

Good afternoon,

Before to post the results of the second round test. I would like to thanks all your advices and feelback. The good results are start to coming up.

Said that, get back to business

Today I proceed with a second round test based on the latest thougths you provide me. Thanks Dave and Cliffcarter.

Test description

1. I pre-heat the smoker to 110F using. lumb charcoals

2. Once preheated I cleaned the FC and using the Minior method I filled it half full.

3. Once I got 150F on the cooking chamber I opened the ash pan in order to inject more air into the firebox.

4. Close the door.

Some general notes about it

1. THe sun light did not hit the smoker.

2. There were a soft air flow hitting the smoker.

3. I used a mix of cheap lump charcoal and brikets charcoals in order to save some money.

These are the results. Please take a look

Schedule	Left thermometer(F)	Right thermometer(F)	Notes
11:05 a.m.	>150	110	None
11:30 a.m.	160	175	None
12:00 p.m.	170	200	I opened the ash pan and close the upper inlet of the FC.
12:20 p.m.	200	225	None
12:47 p.m.	190	215	None
12:55 p.m.	170	205	None
01:25 p.m.	>150	150	None

1. As you can see I archieved to raise the temp to 225F couple minutes after I opened the ash pan of the firebox. I am pretty happy about this..

2. However I could not keep it more than half hour, It could be possible that the cheap lump charcoals did not make a good job.

Now, based on the two previous test cases scenario.  I think I need to take a decision on how to modify the smoker so that it can work better. I would appreaciate your comments.

Thank you

Sergio