PB700 heat problems

[Wannabedivin]

New go smoking. My problem is that the actual barrel temp is significantly different than the display temp. Using an analog gauge and an aftermarket unit designed to measure oven temp
@225 set temp and display, actual barrel temp 185-194
@250 set temp and display temp, actual barrel temp 210-215
@300 set temp and display, actual 295-315
The temp taken at the unit sensor is accurate.
As can be Seen I cannot Get this unit into prime smoking temp. I have played with the p settings seemed to help a bit.
Any suggestions on how to improve the heat distribution?

 

[Redoctapus]

New go smoking. My problem is that the actual barrel temp is significantly different than the display temp. Using an analog gauge and an aftermarket unit designed to measure oven temp
@225 set temp and display, actual barrel temp 185-194
@250 set temp and display temp, actual barrel temp 210-215
@300 set temp and display, actual 295-315
The temp taken at the unit sensor is accurate.
As can be Seen I cannot Get this unit into prime smoking temp. I have played with the p settings seemed to help a bit.
Any suggestions on how to improve the heat distribution?

Welcome to the forum. Some of the other folks may be able to help. Are you getting a good preheat? My PBV5 needs a good preheat to 300* for 20 minutes. Then when I set a low cook/smoke te.p it works fine.
Jussayin...

 

[Wannabedivin]

Welcome to the forum. Some of the other folks may be able to help. Are you getting a good preheat? My PBV5 needs a good preheat to 300* for 20 minutes. Then when I set a low cook/smoke te.p it works fine.
Jussayin...

Haven't tried the preheat. Will give that a shot

 

[brewersfan73]

Just so I'm understanding, are you saying that you have verified the temperature near the PB temp probe and that it seems to be accurate? But your temps at the cooking grate are well below what you want (at least at 225 & 250 setting)? How long did you leave it at the set temperature before taking the grill grate temperatures?

It sounds like the PB temp probe is getting up to the set temperature faster than the rest of the barrel. You could try the heat deflector mod. If you aren't familiar, this is the website: SLAB heat deflector Before you bought or made one, I'd try wrapping foil (probably 3+ layers thick) around the end of your curved drip pan to block the air gap and see if this works. You can see the foil on the left hand side of this picture to give you an idea of what I'm talking about:

As far as adjusting the P value, that only works if you are using the S (smoke) setting on the temp controller. My understanding is that it has no effect when you set the controller for a specific temp.

 

[Wannabedivin]

thanks for weighing in. Been Leaving it at least 30 to 45 minutes after the display reaches desired temp. As far as the air gap goes, this model has one

 

[Redoctapus]

Haven't tried the preheat. Will give that a shot

Once you have preheated the unit lower temp in at least two steps. 300 to 270 then 270 to cook temp desired.

 

[Wannabedivin]

Just so I'm understanding, are you saying that you have verified the temperature near the PB temp probe and that it seems to be accurate? But your temps at the cooking grate are well below what you want (at least at 225 & 250 setting)? How long did you leave it at the set temperature before taking the grill grate temperatures?

It sounds like the PB temp probe is getting up to the set temperature faster than the rest of the barrel. You could try the heat deflector mod. If you aren't familiar, this is the website: SLAB heat deflector Before you bought or made one, I'd try wrapping foil (probably 3+ layers thick) around the end of your curved drip pan to block the air gap and see if this works. You can see the foil on the left hand side of this picture to give you an idea of what I'm talking about:

View attachment 3263

As far as adjusting the P value, that only works if you are using the S (smoke) setting on the temp controller. My understanding is that it has no effect when you set the controller for a specific temp.

Just ran a test. As suggested heated up to 300 then backed it down to 225. I set probes up like you did. After 30 min at 225 grill temp is as follows.
Far left (Firefox side) 239
Mid left 210
Mid right 201
Far right 190
Temp remains constant but are low
At 250 temps act like they should at 225. There is not a setting for 275.
Pulling my hair out
Thanks much

 

[brewersfan73]

Not sure if this helps, or just confirms that you can't get the temperature that you are looking for. We have different sized cookers, but here's the heat distribution on mine:

SMOKE setting from 8:00 AM to 10:00 AM (as you can tell, it was still warming up for the first 30-45 minutes):

Set at 250 degrees F from 10:00 AM to noon:

I'm 100% sure I had the flame diffuser over the burn pot. I'm 95% sure I had a knock-off air gap mod installed on the left side of the drip pan (not the aluminum foil). Again, not sure if this helps at all, but just another set of data points.

Edit: no clue if the smoke tube affected the temperature on the orange probe #2. It seems like it might have a little bit. The temperature around the meat was typically in the 230-250 range in the 10-noon time slot, so I was pretty happy.

 

[Wannabedivin]

My model has five holes in the back instead of a smoke stack. Wondering g I plugging all the holes and installing a smoke stack on the right ( opposite side from the fire pot) would make a difference because the heat would have travel across the cold side to exit. There is a cutout for a stack

 

[Redoctapus]

My model has five holes in the back instead of a smoke stack. Wondering g I plugging all the holes and installing a smoke stack on the right ( opposite side from the fire pot) would make a difference because the heat would have travel across the cold side to exit. There is a cutout for a stack

I have modified a couple smokers after using them a few times. My barrel smokers have stacks with dampers and they all had leaks. I would adjust the chimney damper until I saw alot of smoke coming out the leaks, then adjust the damper open until just a little smoke came out the leaks. I also used crumpled aluminum foil to plug some leaks! Sometimes the wind blows in the wrong direction. If the vents are leeward it's probably better than windward.
Does your smoker have a baffle over the burn pot? Someone here or on YouTube was showing some baffles for barrel smokers, one had square tubes to insert wood chunks for additional smoke. If your burn pot doesn't have a baffle/diffuser maybe check one out. Cowboy1955 seems to be pretty sharp about these things... what say you Cowboy?

 

[Wannabedivin]

No baffel. But since the burn pot is on the left side wouldn't a baffel direct even more heat towards the left side and temp settings sensor. Not an engineer just frustrated. Seems to me that if it was possible have the temp sensor on the cold side instead or above the fire pot

 

[Redoctapus]

No baffel. But since the burn pot is on the left side wouldn't a baffel direct even more heat towards the left side and temp settings sensor. Not an engineer just frustrated. Seems to me that if it was possible have the temp sensor on the cold side instead or above the fire pot

Give the tec support guys a call. I haven't used a 700 so I do not have any first hand experience to share about that 700. Try some of the foil ideas. Pork butts are pretty forgiving about temps, fish isn't so forgiving.

 

[brewersfan73]

No baffel. But since the burn pot is on the left side wouldn't a baffel direct even more heat towards the left side and temp settings sensor. Not an engineer just frustrated. Seems to me that if it was possible have the temp sensor on the cold side instead or above the fire pot

Sorry, I didn't realize that your burn pot was on the left side, so my info probably wasn't very useful.

How about this? This is the same diffuser that I have. I tried a test where I covered up one of the rectangular cutouts with several layers of foil, so basically is was open on three sides. Point the foil covered side toward the temp probe. It didn't make a huge difference for me, but I didn't run a controlled test so it is hard to say. I wonder if someone out there with a 700 series and a flame diffuser could run a test and see if it improves.

 

[Wannabedivin]

Was thinking about this also. Would like to hear from someone who has actually done it on a Pb700

 

[tstreets]

My model has five holes in the back instead of a smoke stack. Wondering g I plugging all the holes and installing a smoke stack on the right ( opposite side from the fire pot) would make a difference because the heat would have travel across the cold side to exit. There is a cutout for a stack

I did this on my PB700. I plugged the holes and added the smoke stack. The temperature still fluctuated although I think it did help some. One thing I found is if the temperature prob is dirty it reads incorrectly and seems to lead to the grill to be hotter then it should be. There is still temperature swings no matter what I did.