This page details operation of the IQ110 on the Rebel 28. The Rebel 28 is a gravity feed type cooker manufactured and distributed by Rebel Smokers (www.rebelsmokers.com). This is the cooker we (pitmasterIQ BBQ) use in competitions. Here are some pictures:
This is the IQ110 inside its protective enclosure. The enclosure is a Bud Industries NBA-10162 painted black (Mouser p/ns 563-NBA-10162, 563-NBX-10911, 563-NBX-10920). Be sure to add the optional vents to the enclosure at the top to allow hot air to escape. Otherwise, the Greenhouse Effect will cause the IQ to think it's overheating on a hot cooker and enter "self preservation" mode and stop blowing.
Here the IQ connects to the Rebel Smokers Rebel 28 via the included 1" hose barb, a 1-1/2" to 1" reducer (not included) and a 90° street elbow (not included). It's important to keep the hose as straight as possible to maximize airflow.
We installed the IQ's temperature probe in a permanent fashion through the back of the cooker. Be sure to figure out where the cooking racks are before drilling!
This graph shows (not very well) a startup timing test done on 11/12/12 followed by an open-door recovery test. The blue line is temperature at the thermometer stem inside the door and the red line is temperature at the IQ's probe at the inside rear of the cooker.
Test Conditions: 30°F, Ozark Oak lump charcoal, no meat load, IQ software version 1.8 in "Max Blow" mode, instrumentation by Omega Scientific.
The fastest way to start a gravity feed cooker is to dump lit charcoal down the empty chute to the firebox, followed by topping off with unlit charcoal. The problem with this method is that it is not always convenient to first empty the chute. For this reason, we start with unlit charcoal in the firebox and light it with mapp gas.
Start by topping off the chute with unlit charcoal. Using an old kitchen knife, agitate the old coals to help any old ash to fall into the ash pan. With the top of the chute still open, light the charcoal with a mapp gas torch from all angles until smoke is seen coming out of the top of the chute. This will take 1-2 minutes. Start the IQ with the intake damper fully open and open the cooker's ball valve fully. Close the firebox door, but leave the chute door open up top. This simulates a charcoal chimney. Don't leave the cooker to go have a beer. You'll forget about it and have a real problem when you return!
Let the charcoal get hot enough to where you can only hold your hand over the chute for about 5 seconds before it gets too hot. This will take 5-10 minutes. With the firebox now full of hot coals, close and latch the charcoal chute. The cooker's door should also be closed. To keep the fire as hot as possible, open the firebox door and agitate the coals with the old kitchen knife every 10 minutes.
Set the IQ for 25° hotter than you want to cook (250 if you want to cook at 225). This will cause the IQ to blow right through the setpoint as quickly as possible. When you get to the desired cooking temperature, load your meat and set the IQ to where you want it to hold it.
In the graph above, the cooker climbs from 35° to 240° in 55 minutes. Add in the 10-15 minutes for get the firebox hot and you're at 65-70 minutes to start up. If you're not in a hurry, you can just light the coals, close everything up and wait, but this method can take as long as 2 hours to get to temp. At competitions, we start the cooker at least 3 hours before we plan to load meat.
Open-Door Recovery Test:
In the above test, the door was opened wide for 30s. No heat retaining panels were in place. Ambient temperature was about 35° but no wind was blowing. The temperature at the thermometer stem dropped to 170°. The door was closed. The "Max Blow" mode of the IQ disables the door open detection feature of the IQ, so it begins blowing at its maximum speed immediately without pulsing on and off. The temperature passed back through its original temperature only 5 minutes after closing the door, although this was without a meat load.