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How long can my 640 run non stop?

PostPosted: July 2nd, 2017, 11:07 am
by Jfrederick
I did my longest cook yet yesterday on the 640. I typically do 12hr ish cooks with 10-12lbs packers but the only prime packer I found this weekend was 17.25lbs. I fired my cooker up and put the brisket on at 11pm and pulled at 5pm the next day (was amazing btw). Toward the end of the 18hr cook my temps where quite unstable. In fact I had to run the cooker at 300* to get my Thermoworks Smoke to register 230*. Every cook I have ever done in two years the grate temp, door gauge and controller are within 10 degrees.

This morning I went to clean the beast and found that the firebox grate is so full I think I was close to having a hopper fire.

I burn 100% hickory pellets. BBQers Delight. Buy locally at ATBBQ. I store them properly, just like Herb suggests.

My question: How long can I really run this cooker before I need to shut off and clean the firebox? Based off this experience I'm saying 15-17hrs max?

Looking for feedback. See attached pics after my cook.

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IMG_9602.JPG (50.02 KiB) Viewed 5304 times

Re: How long can my 640 run non stop?

PostPosted: July 2nd, 2017, 11:37 am
by jeetS
Wow! I've done 20hr cooks and the firepot wasn't even close to that full...
Assuming you started with a clean burn grate i'd say there was something wrong with your pellets... Maybe you got a bad bag?

Re: How long can my 640 run non stop?

PostPosted: July 2nd, 2017, 12:53 pm
by Jfrederick
Yes, started with completely clean grill! I always vacuum the firebox before a big cook and after a few short cooks.

Not sure, could be a bad bag?

Re: How long can my 640 run non stop?

PostPosted: July 2nd, 2017, 8:37 pm
by Yoder_Herb
Check to make sure that both fans are running.

Re: How long can my 640 run non stop?

PostPosted: July 3rd, 2017, 7:26 am
by Jfrederick
I'll check that and report back.

Re: How long can my 640 run non stop?

PostPosted: July 3rd, 2017, 5:14 pm
by Jfrederick
Here is what I did...

I emptied the firebox and turned the power switch on to activate the fans. I felt little to no air flow from the fans into the firebox visually the fan on the far side of the hopper was running. I turned the power off, opened the box and spun the fans by hand and they felt good. I put everything back together and it ran great and there was a lot of air flow into the cooker. No idea what I did......

I than got to looking and thinking and I believe what happened is the plastic connector for the ignitor was laying infront of the internal fan, which I remembered moving to turn the internal fan. I relocated that connector when I had it all apart. I bet the connector was impairing the internal fans ability to turn. Make sense?

Either way... throwing 4 racks of ribs on tomorrow with beans and bacon wrapped poppers. I'll check it tomorrow after my cook and report back.

Re: How long can my 640 run non stop?

PostPosted: July 3rd, 2017, 6:18 pm
by Yoder_Herb
Jfrederick wrote:Here is what I did...

I emptied the firebox and turned the power switch on to activate the fans. I felt little to no air flow from the fans into the firebox visually the fan on the far side of the hopper was running. I turned the power off, opened the box and spun the fans by hand and they felt good. I put everything back together and it ran great and there was a lot of air flow into the cooker. No idea what I did......

I than got to looking and thinking and I believe what happened is the plastic connector for the ignitor was laying infront of the internal fan, which I remembered moving to turn the internal fan. I relocated that connector when I had it all apart. I bet the connector was impairing the internal fans ability to turn. Make sense?

Either way... throwing 4 racks of ribs on tomorrow with beans and bacon wrapped poppers. I'll check it tomorrow after my cook and report back.


BINGO! Glad you found the issue.

The igniter plug should be pushed through the small opening in the fan tunnel, so that it is outside of the fan tunnel, and in the hopper area under the controller,

Re: How long can my 640 run non stop?

PostPosted: July 6th, 2017, 7:14 pm
by Jfrederick
The fixed it for sure! Smoked ribs for 6 hours on the Fourth of July. Cooker ran great, temps where very stable and below is a pic of the firebox after 6 hours. Much more normal looking. Who would have thought that internal fan was so important? Lol.

Also - I have added a step to my start up procedure. Once I hit start and close the lid I put my hand over the smoke stack and make sure there is airflow. If that internal fan is not running you will feel no airflow, if it is running you will feel a nice steady flow of air.

IMG_9615.JPG

Re: How long can my 640 run non stop?

PostPosted: February 12th, 2018, 2:23 am
by stux
Jfrederick wrote:The fixed it for sure! Smoked ribs for 6 hours on the Fourth of July. Cooker ran great, temps where very stable and below is a pic of the firebox after 6 hours. Much more normal looking. Who would have thought that internal fan was so important? Lol.

Also - I have added a step to my start up procedure. Once I hit start and close the lid I put my hand over the smoke stack and make sure there is airflow. If that internal fan is not running you will feel no airflow, if it is running you will feel a nice steady flow of air.

IMG_9615.JPG


Just finished a non-stop 24 hour cooking session on the weekend :)

Can confirm that my burn grate pretty much looked like your improved photo ;)

100% BBQ'rs delight Hickory pellets.

pre-burnt in a new diffuser for 90 mins, then an 18 hour pulled pork session... which turned into continuous ribs as butts came off and ribs went on in their place.

Started the fire up ta 8pm, finished at 8pm the next day :)