Trouble hitting and maintaining 400F with blower


 
A

AubreyW

TVWBB Member
HM 4.1 with Auber 6.5cfm blower on a Kamado Joe Classic. I can do low and slow just fine but I'm having a heck of a time with a midrange temp.

400f is easy without hm, but with hm I struggle to get to temp. Max fan is 25%, tried top vent totally open or 1/4 open as I would without hm. Going above 25% max fan appears to cool the fire and not help.

Stock PID settings, thanks for any help!
 
AubreyW said:
HM 4.1 with Auber 6.5cfm blower on a Kamado Joe Classic. I can do low and slow just fine but I'm having a heck of a time with a midrange temp.

400f is easy without hm, but with hm I struggle to get to temp. Max fan is 25%, tried top vent totally open or 1/4 open as I would without hm. Going above 25% max fan appears to cool the fire and not help.

Stock PID settings, thanks for any help!
Click to expand...

use max fan, it will cool at first but after a bit the heating will overcome the cooling, atleast it should
 
AubreyW said:
HM 4.1 with Auber 6.5cfm blower on a Kamado Joe Classic. I can do low and slow just fine but I'm having a heck of a time with a midrange temp.

400f is easy without hm, but with hm I struggle to get to temp. Max fan is 25%, tried top vent totally open or 1/4 open as I would without hm. Going above 25% max fan appears to cool the fire and not help.

Stock PID settings, thanks for any help!
Click to expand...

It's possible that the holes in the stock KJ grate are getting clogged. I made this grate out of 2 weber smokey joe fire grates, with 2 grates offset by 90 degrees. Since then, I've been doing low and slow and hot and fast without any problems using the heatermeter.

20Y1fSTl.jpg


99XqsGul.jpg
 
I'll try max fan, thanks. I have an expanded diamond metal grate I got from eBay similar the one shown above, so I don't think clogging is the problem. Thanks to both of you!
 
Hi,
How does the air flow through your smoker? Does it hit the coals from under the crisscrossed grates or through the (6?) Holes in the ash pan ?

Looks like some air may be flowing around the ash pan, and that would lower the pit temp if it is not hitting any burning charcoal.

Are you using briquettes or lump ?

I have seen a lot of variance in temps when using natural lump... Temps can drop even when the fan is at full tilt if the lumps are large.

To get higher temps, I would break up the large lumps to get to an average size near briquettes.

Also I think you will get more heat with natural lump charcoal than when using briquettes.
 
Using natural lump that I start in a chimney. Fire bowl air hole is lined up with blower so most air should be going in under coals.
 
Did a 350 cook and recovery was very poor after each lid open. I'll post my graphs next time. Something's not right.

Max fan was 100%.
 
Did a test run to try and figure out what was going on with the Auber 6.5cfm blower. Here's my timeline and the graph below:

2:55 started charcoal in chimney starter
3:05 dumped charcoal into grill
3:07 installed pit probe on dome thermometer stem
3:08 plugged in Auber fan in normal orientation (flap functional), unable to go above ~300F even though setpoint was 400F
3:13 flipped Auber fan so flap is down (no impact on airflow), still unable to push temp above 300F
3:15 changed to RotoDamper, fan and damper active 4,3,.005,5, temp climbed nicely to 400F, a little oscillation

I always thought the Auber would deliver MORE airflow because it wasn't restricted like the rotodamper but I was wrong. I will note that the Heatermeter stock fan, the one I use on the Rotodamper, is bigger than the Auber so maybe it's not so surprising after all.

EtkdGj2.jpg


Conclusion? The Auber does not have sufficient airflow to operate above 300F. It should be fine for low and slow BBQ temps such as 225-275, but for roasting or anything where you want higher temps it is now working on my setup. Can you find any holes in my experiment?
 
Last edited:
Did you do this work before or after working on the PID settings ? I did not see in this graph where the Auber was being driven at 100% but after the switch to the Rotodamper and stock fan the graph shows it driving to 100%...

5 cfm of air can make a pile of burning charcoal go over 1500 degrees under the right conditions (lump size and volume of coals).
 
Experiment with the Auber was before messing with PID, maybe I posted the wrong graph, sorry, but 100% is 100%, right? And the Auber wasn't cutting it, at least on my setup.
 
I find all of this a little bit odd, cause when I use the stock blower into a roto damper with the blower allowed to run at 100% there is a pretty solid breeze coming out of the damper. I have no problem running my Fauxmado in the 500F range with this setup, to run in the 500-800F range I bump up the blower to a larger size but only run it at 50% Max cause it makes a lot of noise at 100% and 50% provides plenty of flow. Are you sure the damper is fully open when the HM is at 100%?
 
Ralph, the roto damper with stock fan performs just fine, no complaints. It's the Auber 6.5cfm blower that won't go above 300f.
 
AubreyW said:
Ralph, the roto damper with stock fan performs just fine, no complaints. It's the Auber 6.5cfm blower that won't go above 300f.
Click to expand...

Good to hear... Doesn't the Auber blower have some sort of gravity flap? Maybe it is stuck or not moving freely or not opening all the way?
 
It does have a gravity flap. I tried it right side up and upside down. Upside down keeps the flap out of the way and in either case the temp wouldn't go above 300.
 
Maybe you got a bum fan? If you connect it to 12VDC does it blow a similar amount as the stock HM blower? They're rated pretty much the same, 6.5 or 6.7 CFM....
 
You must log in or register to reply here.

 

Back
Top