Flame Boss FB400 Wi-Fi Review

Flame Boss FB400 Wi-Fi Review
The Flame Boss 400 Wi-Fi is a thermostatic controller designed to regulate the temperature of a charcoal-fired cooker like the Big Green Egg or the Weber Smokey Mountain. It works in conjunction with a free Android or iOS app or on the company's website via any browser. It is easy to install and provides excellent temperature control.
The unit comes with a manifold to attach the blower to the cooker's lower vent. There is also a fitting for attaching the unit to a cooker with a threaded coupling. Intallation took only a couple of minutes and didn't require any tools.
Two temperature probes are included, one for the cooker temperature and one for the food. The former provides feedback about the internal temperature of the cooker. The cooker temperature is compared to the target temperature set by the user. If the cooker temperature is below the desired value, the Flame Boss controller increases the power to the fan, increasing airflow. Increased airflow raises the temperature. Similarly, if the cooker temp is too high, the airflow is reduced, and temperatures will drop. The trick with controllers like this is compensating for the lag between increased airflow and increased temperature. If the controller doesn't add or subtract airflow in the right amounts, the temperature can fluctuate wildly. This controller was very well behaved.
I conducted this test while cooking some ribs on a cool day (60°F, 13°C) with no wind on an 18.5 inch Weber Smokey Mountain. I filled the fuel tray about half full with Kingsford charcoal briquets and lit about a half chimney of the same fuel. Once the briquets in the chimney were covered with ash, I poured them on top of the unlit charcoal, added some hickory and assembled the smoker. After the temp rose to my setting of 225°F, I removed the cover and put the ribs on the upper grate. I placed the temperature sensing probe about 2-3 inches from the food. I did not use a probe to track the meat temperature. Here is a graph of the temperature vs. time. (Click on image to enlarge.)
Plot of Temperature vs. Time
The temperature dip just before noon was the result of removing the cover to add the food. The controller sensed the rapid drop in temperature, alerted me that the cover had apparently been removed, and correctly delayed powering up the fan. After a minute or so, the controller resumed fan control and the temperature stabilized at my setting of 225°F. For the next two hours, the temperature barely fluctuated. After a couple of hours, the build-up of ash on the coals caused the temperature to begin to oscillate a bit, so I jostled the fuel and the temp settled back down. As you can see from the graph, the fan output was only a small percentage of its capacity, suggesting that the unit could maintain temperature in much colder conditions. The temperature regulation is the best that I have observed to date.
The 400 Wi-Fi has no controls or display on the hardware itself; it must be controlled from a phone, tablet or web browser. It communicates with the cloud via the user's home router, making its control functions and readouts accessible anywhere an Internet connection is available. Once the unit is set up with the SSID and password of the router, it will connect automatically when powered up. It remembers previous settings, so you could just plug it in and start cooking. If you are using the meat thermometer, you can specify at what temperature the app will announce that the food is done, and when that temp is reached, you can set it to reduce the cooker temperature to keep the food warm. The website mentions that you can set a timer, but I couldn't figure out how to do that. Aside from audible/visible notifications generated by the app, you can also set up e-mail notifications if the cooker's temp goes outside the limits you set or when the food is done.
I ran this test using an optional battery pack (YB1204500-USB) that can power the unit without the AC adapter. Its nameplate rating is 4500mAh at 12V or 9000mAh at 5V. It has five tiny LEDs that indicate its state of charge. I charged the battery fully before I began. After nearly five hours of use, including supplying power to another thermometer I used for data collection purposes, it still showed four lit LEDs, so the capacity should be more than adequate for even the longest cooks.
The Flame Boss 400 Wi-Fi has only one food probe, but that is probably not a deal breaker for most cooks. The documentation for the app is on the sparse side - apparently we're supposed to be able to figure it all out by ourselves. I like that I can access and control the unit via a web browser. From the website, you can also download the raw data - time, temperature and fan data - but the data's units are not specified. I had the target temp set at 225°F but the downloaded data showed 1072, and the fan's numbers are similarly cryptic. Unless you plan to plot the data using Excel, this probably isn't a big deal.
Setup is easy and the temperature control is excellent. The app has the basic functionality needed to control your cooking session, and the data is retained in the cloud. One minor glitch - and I do mean minor - is that the unit will not reconnect with the router if the router is shut off and then turned back on. You have to power down the controller and then power it back up to re-establish communication. The price is lower than most of its competitors and the quality of the unit and the temperature probes is good. Overall, this unit gets a Gold Medal for ease of use and performance.
Thermometer Function: 
Thermostats/Temperature Controllers
Manufacturer's Suggested Retail Price: 
Controller, 2 probes, universal adapter, power supply, minimal instructions
Food: length: 3.75" (95mm), diameter: 0.127" (3.2mm), cable: 72" (1.8m); Cooker: alligator clip, cable:
Optional battery pack
Battery type: 
AC adapter, optional battery
Battery life: 
Not specified
Min / Max: 
Not Specified
Ambient operating temperatures: 
Not Specified
Display precision: 
At 130°F it actually reads: 
At 225°F it actually reads: 
At 325°F it actually reads: 
Speed from 32°F to 212°F: 
Size of numbers in display: 
Water resistance rating: 
Not Specified
0.45 lb. (204g)
In cloud
C/F Switch: 
Auto shutoff: 
iOS and Android and Web browser

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About the features, specs, and technical terms

Adjustable. The accuracy of some thermometers can drift, and these thermometers can be adjusted to bring them back to the correct reading.

Alarms. Some devices can be set to alert the cook when a high or low temp is reached either with an audible alarm such as a beep or a visible alarm such as a flashing display.

App. Bluetooth and Wi-Fi enabled devices have a smartphone or tablet app that talk to the device.

Auto shutoff. If you don't use the device for a set period of time, it will shut itself off to save batteries.

Backlight. Digital thermometers are hard to read at night unless they have a backlight.

Bi-metal dial thermometers. Most bi-metal coil dial thermometers mounted in grill hoods should be called heat indicators, not thermometers. We do not recommend them. They have round clock-like readouts and the sensor uses two strips of metal bonded together and rolled into a coil. Each metal expands at a different rate, turns a shaft, and this provides the reading on a dial. Bi-metal meat thermometers can take up to 30 seconds to give a final reading and because the sensor can be 1/2" long or more they cannot read a specific location in meat. Most thermometers built into grills and smokers are bi-metal, but they are often low quality in order to keep the grill price down. They can easily become unreadable if they fill with smoke and or water. Also, these grill thermometers are mounted in the dome, where the temp can be very different from the temp at the cooking surface, which generally makes these bi-metal dial thermometers both unreliable and misleading.

C/F Switch. Most thermometers have a switch to change the display from Celsius to Fahrenheit.

K-Probes. Some thermocouple thermometers have a standardized spade-like connector for scores of interchangeable probes.

IR (infrared) sensors. Infrared-sensing thermometers measure the energy radiated from a warm surface and convert it to a temperature reading. Some surfaces emit more infrared at a given temperature than others, so some units allow the user to adjust the emissivity setting to fine-tune the accuracy of the thermometer. This should rarely be necessary unless very high accuracy is needed. These units are useful for determining the temperature of a cooking surface like a skillet or griddle.

Liquid filled thermometers. Old-fashioned liquid filled thermometers are very small glass tubes filled with a liquid that sits in a bulb at the bottom. As it warms, the liquid expands. These thermometers are slow but they can be very accurate. Because they do not need batteries, they make good refrigerator and freezer thermometers, but they cannot read a small area such as the center of a hunk of meat well.

Logging. Some thermometers can remember the readings taken over time and create a log that can either be printed or exported to a spreadsheet.

Margin of Error. Most thermometers are considered to be accurate if they are within plus or minus 3°F of the target temperature. High end thermometers are more precise than this.

Min/Max. The minimum and maximum temperatures it is capable of reading. On some devices, especially those which use different probes, the Min/Max can vary with the probe.

Oven. We often use the term "oven" to cover a range of cooking devices, including grills and smokers, which are essentially outdoor ovens.

Popup thermometers. Popups have a compound in the tip that melts at a determined temp and releases a spring that pops the stem up. This type of thermometer often comes pre-inserted in your Thanksgiving turkey. Although there is a chance that it will be accurate, the thermometer will read only one small part of the turkey, may stick, and will likely be set to a high temperature that is meant to prevent litigation rather than produce a juicy bird. The popup thermometer is often to blame when your turkey tastes like cardboard. Throw it out.

Price. Usually the manufacturer's suggested retail price. When that is not available, we use the approximate street price.

Sensor. Thermocouple, thermistor, liquid, and bi-metal. They are each described in detail above and below.

Speed. We measure how long it takes the thermometer to go from 32°F to 211°F and from 212°F to 33°F. But you have to be careful about the time manufacturers quote. Often they use an industry standard called "time constant." That is the time it takes to get to 63% of a full reading, and a full reading takes five times that. So if they say the time constant is 0.6 seconds, as does the manufacturer of the Thermapen, the unit will be precise with a full reading in about 3 seconds. Another factor to consider is how fast the display refreshes itself. The Thermapen refreshes every 0.5 seconds. This means you can slowly insert it and remove it and it will give you a new reading every 0.5 seconds. The Thermoworks K-type Fast Response Meat Probe #113-151, which can be plugged into different meters, is slightly faster with a time constant of 0.5 seconds and precise read in 2.5 seconds. But if you plug it into the MTC meter, which refreshes every 1 second, the probe is actually faster than the meter, and combined they are slower than the Thermapen. Another factor is the conductivity of the medium you are measuring. Food, which consists mostly of water, reads faster than bread, which consists mostly of air. That is because water is a better conductor than air.

Thermistors. Thermistors are usually not as quick as thermocouples. They tend to be thicker, and they can be slightly less accurate, usually with a margin of error of 5°F. These sensors are best for leaving in large roasts and ovens for continuous readings. Thermistor units send a current through a wire in the probe with a resistor in the tip. Its resistance to the electrical flow changes with temperature and the meter measures the voltage across the resistor.

Thermocouples. Thermocouples are the best food thermometers because they're fast and precise with a small sensor, making them ideal for rapid read thermometers. Their margin of error can be less than 1°F. Thermocouple probes have two tiny wires of different metals welded at the tip, most often nickel and chromium (called Type K). The heat causes a tiny voltage to appear across the dissimilar metals, which are connected to a meter that measures the voltage and calculates the temperature.

Water resistance rating. Some manufacturers simply specify that a thermometer is "water resistant," but this is not a regulated description and should be taken with a grain of salt. Some manufacturers use a third party service, the International Electrotechnical Commission (IEC). It rates devices using an International Protection rating code (an IP code). An IP code might look like this: IP65. The first digit quantifies protection against solids like dust, and the second digit quantifies protection against liquids. The digits range from IP00 to IP68. If a thermometer is rated IP65, it was tested and found to be completely protected against dust as well as protected against low pressure jets of liquid from all sides. So it is OK in the rain, but NOT protected against a swim in the BBQ sauce.

Where to buy. We provide links to some suppliers, especially to those who pay us a finder's fee if you buy from them. In some cases, our links provide a Compact AmazingRibs.com Meat Temperature Guide along with the product. You will only get the guide by following the link provided.

Best Value Awards

Gold Medal. Among the best of its type in its price category. A strong buy recommendation if this is your budget.

Silver Medal. A fine product among the best in its price category with only minor shortcomings. Recommended for purchase if a Gold Medal is not available.

Bronze Medal. A good product, better than average, but may be lacking in features or quality compared to higher rated products. Worth considering for purchase if you cannot find or afford a Gold or Silver Medal.

Not Recommended. These are products that we think are poor choices compared to competitors based on price, features, and construction quality.

Not Judged Yet. These are products that may be award caliber, perhaps even Gold Medal caliber, but we do not know enough about them yet to give them an award.

How We Test, Review, and Rate Thermometers

We purchase almost all of the thermometers we review. These are truly unbiased reviews. We do not make or sell anything, and our advertising is sold by third party ad networks. We are not involved in the process. Rest assured that when we recommend a product, it is really because we like it, not because someone has paid us to say so or because the company is an advertiser or sponsor. Manufacturers are never charged to have products reviewed or be included in the listings.

Bill McGrath, an electrical engineer, does all our thermometer testing, ratings, and reviews. He uses special equipment calibrated and rated by the National Institute of Standards & Technology to check the accuracy and speed of thermometers. He uses an ice water bath and a boiling water bath to measure the time it takes each thermometer to go from 32° to 211°F and to go from 212° to 33°F. After taking objective measurements, he evaluates based on subjective criteria such as ergonomics, ease of use, flexibility, warranty, access to support, and build quality. Finally, we consider value when giving our awards.

nist calibration machine

"The instant-read thermometer, used frequently, solves most issues." --Mark Bittman, New York Times food columnist and cookbook author

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