Connections
In the photo below left, we have turned the system unit sideways to show where the connectors are. The front view shows you how the connectors are labeled:

The connector on the top is for the food probe. The connector right below that is for the pit probe. Finally the jack below those two openings is for the power plug. You can either use the supplied "brick" power supply or they also sell a cigarette lighter adapter that you can plug into one of the many automobile starter batteries available which have a cigarette lighter outlet on them. The plug on the adapter must have a positive center connector.

Pit Probe
The IQ120 comes with a temperature probe for monitoring the cooker temperature:

The probe itself is made from stainless steel and contains a platinum RTD sensor rather than a thermocouple that other brands have. What's a platinum RTD sensor? You may wish you hadn't asked, but here goes.

First of all, a thermocouple works on the Seebeck effect. When two ends of a conductor (wire) are at different temperatures, a voltage is created between the two ends. The magnitude of the voltage depends on the temperature difference between the two ends. If you take two conductors made from different materials, there will be a different voltage created in each conductor. Then if you connect the two conductors at one end, the two voltages will add producing a voltage across the two conductors that varies with temperature. With me? If you know the materials, then you know the voltage generated for each temperature and this then gives you the DIFFERENCE in temperature between the two ends of the pair of conductors. Finally, you put a thermistor inside the meter that the probe plugs into to tell you the temperature of that end of the pair of conductors. Voila! You know the temperature of one end of the pair of wires, and you know the temperature difference between the two ends. Therefore you know the temperature of the other end! Simple, eh?

Well, platinum RTD sensors work like this. Many materials have an electrical resistance that varies with temperature. So if you can measure the resistance, you know the temperature. Platinum is a popular material for this type of sensor. You pass a small current through the sensor, measure the resistance and deduce the temperature.

What's the difference? Thermocouples are faster reacting and can measure much larger temperature ranges. RTD sensors are more accurate and more stable. So we asked the maker of the IQ120 why they chose to use RTD sensors and it turns out that an RTD sensor does not need to be calibrated to the unit. A thermocouple should be calibrated to the unit being used. In light of the fact that the original iQue 110 had no numeric temperature readout, you couldn't really calibrate it. Having a probe that didn't need calibration was therefore pretty much a necessity. Also, the reponse time is not a critical factor in this application and the RTD sensor is more accurate.

The wire has an armor braid and can withstand temperatures up to 500°. Be careful not to kink the wire. The junction where the wire enters the probe doesn't appear to be sealed, and the manufacturer recommends that you avoid getting this junction wet.

The probe and the wire should be shielded from direct radiation from a hot fire. Do not let it come into direct contact with flames. If you need to shield the wire, you can place a layer of aluminum foil beneath it. Also, having the pit probe itself exposed to direct radiant heat can cause it to register a temperature which is higher than the air temperature in the cooker, and thus fool the controller into cutting back on the fire. (If a probe does fail, you will be able to tell because the controller will display "Probe Error" when it detects a faulty probe.)

An alligator clip is provided which you can use to clip the probe to your dome thermometer or the food grid, as you see fit.

Food Probe
The IQ120 also comes with a temperature probe for monitoring the food temperature:

The food probe is also made from stainless steel and also contains a platinum RTD sensor. The same caveats apply as with the pit probe regarding exposure to heat, flame and moisture. Obviously, the presence of a food probe allows the unit to monitor the food temperature and sound an alarm when the food is done using the "Food Alarm" setting. It also allows the cooker to change the pit temperature to a new setting when the food reaches a certain temperature using the "Food Temp" and "Food Pit Set" settings.

Also note that the plugs for the pit and food probes are the same type, so be sure you plug each probe into the into the correct jack on the system unit lest you control your food and monitor your pit instead of monitor your food and control your pit! The probe plugs are color-coded (pit is black and food is red) to help you out. In a pinch, you can use either probe to monitor the pit temperature. The alligator clip will fit on the food probe.

Temperature Probe Accuracy
How accurate are the probes? We measured the temperature of boiling water using both the pit and food probes. The pit probe was spot on. It appeared that the food probe read about 1.5°F high. It turns out that there is a very small flaw in how the unit calculates the temperature read by the food probe. 1.5°F is negligible unless you were somehow trying to use this with a charcoal fueled sous vide machine. This will be addressed in future units. However, in general as we stated earlier, platinum RTD sensors are more accurate than thermocouples and this small error is no worse that some of the other thermocouple probes we have tested.

Calibration
RTD sensors don't require calibration, so there is no procedure for calibrating the unit.

The Blower
Now let's take a look at the blower which feeds air to the fire in the cooker. First off we have photos of the blower:

Like the IQ110, the IQ120 utilizes an integrated blower. No separate blower and extra wire to manage. The blower is a variable speed blower which is controlled by the unit to deliver between 5 and 15 CFM, as the situation requires. And unlike the IQ110, the IQ120 has an integrated damper. You can see in the photo above on the left that the damper is set to position "4" and the damper is wide open. In the center photo above, the damper has been set to position "3" and the damper is 50% open. You can use the damper to reduce the amount of air delivered when using an efficient cooker at a low temperature. The photo above on the right shows the hose which exits the system unit and attaches to the adapter on your cooker to deliver forced air to your cooker.

The adapter for kamado style cookers is made from stainless steel and slips into the lower vent grooves. You can then close the lower vent door to hold it in place. The rubber hose from the IQ120 just slips snugly over the tube in the adapter. The adapter is improved over the one used with the IQ110 as it now is sized so you can slip the adapter into the lower groove on the lower vent, and then slide the clip up into the upper groove. No more bending the tab on the lower vent to slide the adapter into the vent grooves. While the adapter will also fit on a medium Big Green Egg, the vent on a medium Big Green Egg cooker has a sharper curve to it and you may find you have to bend the IQ120's adapter a bit to help it fit into the curve.

A bit more about the rubber hose. You might be concerned that it is a rubber hose off a vacuum cleaner, but it is actually high quality EPDM (ethylene propylene diene monomer) rubber made by people who make high quality respirator hoses for emergency responder gear. One of the properties of EPDM rubber is excellent resistance to heat. It's maximum service temperature is 302°F. So there's no worry that it will melt or degrade over time.

Along with the adapter itself comes a kill plug you can use to cover the adapter tube when the rubber hose is disconnected, and it also comes with a clip/clamp that lets you ensure a tight connection between the hose and the adapter.

pitmasterIQ.com has other adapters available for other brands of cookers.

Audible Alarm
The IQ110 had no audible alarms, but the IQ120 has added an alarm that is used for a number of things. The following conditions will cause the audible alarm to sound: The system unit is over temperature, probe error, food done, pit hot and pit cold. The audible alarm can be silenced by pressing the dial button on the face of the controller. The volume of the alarm can be set and the alarm can be disabled altogether in program mode where you are able to set system parameters and settings.