Owner's FAQ

Last updated: May 2024

About Firmware

The most important functions of the Predictive Thermometer are software-controlled — there's a remarkable amount of computing power stuffed in there. The onboard processor makes all kinds of important calculations, including predictions.

The more cooking data we feed into our algorithm ( Predictive Engine), the better it gets. Our new Predictive Engine is better than the one from a month ago (and the next one will be even better). 

It also means we can add new features like advanced cooking predictions or USDA safety guidelines, without you having to buy new stuff!

New firmware is like getting a free* upgrade to your hardware.

(*Yes, it's not technically free because you already paid for the product, but it's a bonus.)

You'll need the app to apply firmware updates. Look in the footer for links.

For information on the newest firmware and app updates, check the product release notes.


Can I upgrade my firmware with someone else’s phone?

Yes. You can use almost any Android or iOS device (for instance, an iPad) to update the firmware. The entire process usually takes less than five minutes. 

You don’t need to create an account or enter any information. The phone is not permanently associated with your Thermometer or Display and your friend can uninstall the app afterwards.

Later, you can use a different device (as long as it has one of the Combustion apps) later -- if you want to -- to display cook data and interact with your Predictive Set.

Or to do another update. Whatever works. 

Is there a cheat sheet for display controls?

Yes! At the bottom of the Display set-up page.

How do I compensate for carryover cooking/resting?

The best way is to slice your meat immediately so that it cools faster.

But that’s not always an option. We’re working on a two-part prediction to manage carryover cooking.

The challenge is putting a second prediction on top of the first (time to cook) prediction; the mathematical model gets wobbly if that first prediction is not entirely stable. We need more data to get the primary prediction 99% trustworthy before we add carryover predictions. That process is ongoing, but it won’t be long before that’s dialed in and we can add a second prediction. 

The main advantage of resting is that the food firms up as it cools, which makes slicing easier (and tidier). If you are cooking something that must rest (like a whole turkey), the rule of thumb is to set the “cook-to” temp about 10% below your real target temp.

Pull the food when the alarm goes off but leave the thermometer in and don’t cut into the meat until the carryover has done its thing (when you’ve reached your real target temp).

You can set a second “cook to” temp for your real target temp after you remove the food from the heat. It won’t predict “time to cook” but the alarm will sound when it gets there.

Cooling is a function of surface area (more surface area→faster cooling) and mass (more mass→more stored heat energy→more rise in temperature=carryover cooking). 

What temperature should I cook ___ at?

That’s a personal question. Depends on how you like it!

We’re big fans of medium-rare for most things (yes, even chicken and pork).

But those temp targets can be significantly lower than the USDA* standard (simplified) guidelines.  

USDA simplified standards are based on the lowest-common denominator quality of ingredients.

The CPT (Predictive Thermometer) now includes an onboard USDA safety feature! Using this you can select "Integrated" USDA cooking standards.

With integrated standards, the CPT tracks TIME as well as TEMP to measure bacterial destruction.

The upshot is that you can cook your food to a lower core temp (juicier! more tender!) while still destroying the 99.99999% of bacteria the USDA recommends for safety.

Your food can be both safe and delicious.

More details here.

Personally, I cook my steaks to 128ºF and my pork chops to 140ºF, thanks for asking.

(*United State Dept of Agriculture)

Can I use it for _____?


There's a comprehensive list on the FAQ, but here are the common exceptions.

Don't use your CPT for this:

  • Candy-making
  • Pressure cooking
  • Deep-fry oil*
  • Broasting
  • Going directly from somewhere hot into an ice bath
  • Microwave
  • Trivection (another kind of microwave)

*You can deep fry with it as long as the lower sensors are protected - if you want to temp your oil, use food to protect the sensors - for instance, a potato.

I have a different question?

Great! We're just getting started with this Owner's FAQ.

If you're having issues, there's a simple troubleshooting guide below.

For cooking/use questions, you may have luck with our dedicated subreddit - it's a friendly community with many questions and answers.

Psst... Chris (our founder) regularly checks in there, and his answers tend to be comprehensive!

For the quickest results, search your question in google, but include the words "reddit" and "combustion inc".

We also welcome questions via email. It's the slower option, but we aim to always answer by the next business day. Ask away!


Simple troubleshooting

Prediction missing or slow-to-predict

Prediction will usually resolve about 10% through the cook and get more accurate as it gets closer to done.

With very long cooks (e.g. smoked brisket), the core temperature will tend to "stall" at a certain temp for a long time.

Predictions will not resolve/stabilize until the stall breaks; remain calm and stick to your cooking plan.

Stall temp + duration predictions are a planned addition to the predictive engine in 2024.

Not seeing surface temp

Surface temp is activated when a target (predict) temp is set (cooking mode). Set a target temp using either the app or the Display.

Not seeing graph

In cooking mode, tap any temp to show the graph (you can hide it in “settings”).

Poor range (smoker, grill, or sous vide)

Move the first range extender (Booster or Display) as close as possible to the cooking apparatus.

If possible, establish a clear line-of-sight between MeatNet™ tools.

Common radio obstructions include metal, water, brick, reflective glass, and human beings.

Display/app stopped showing temp (while cooking)

Disconnected - move closer or reposition to avoid radio obstacles.

Booster misbehaving

Not boosting? Remove CPT from Booster to activate range-extending mode.

Not blinking? Press the button (light) to wake.

Booster not communicating with Display? Follow the directions in "Booster set-up" to link multiple tools:

Start by updating the firmware on all devices* (if you haven't yet).

Then do this:

  1. Put probes in Boosters (this turns Booster radio off) and turn off Display (hold start/stop)
  2. Put all devices within a couple inches of each other
  3. Remove probes from Boosters and turn on Display, and set probes in the pile of devices
  4. Let all devices sit for 1-2 minutes

After that, they're all linked together and will relay signals from any linked thermometers.

App not connecting/intermittent disconnects

Restart phone to clear Bluetooth cache (yeah, it’s annoying).

Some phones (iOS) have a habit of holding stale Bluetooth connections and all the "parking spots" may be full. You may need to do a hard reset.

CPT not connecting to Display and/or App

"Not connecting" is a general symptom that can have a few different causes.

Thermometer in standby? Remove CPT from charger/booster.

It could mean the thermometer's battery is dead - that's usually because there's something interfering with charging.

Dirty contact?
Hey, it happens. If the charging contact (on the butt of the handle) is not making a good connection with the charger/Booster, the CPT won’t charge.

Scrub the contact with steel wool (it won’t hurt it) and see if you get a charge going. The charger light will turn from green to red (or amber) if the cleaning helped. After a full charge, try connecting.

For fully charged CPTs, an incomplete firmware update can prevent connection

Did you recently update the firmware?

Rarely, the thermometer may only partially update the firmware, leaving it uncommunicative. Although it may be fully charged, it will not communicate with either the Display or the App.

Very frustrating!

You can undo this but it takes time.

Leave the CPT outside of the charger/Booster for 48 hours. That will reset the firmware to factory settings so you can redo the firmware update.

Be sure to get the newest app version before applying firmware updates.

(Links to app downloads are in the footer, or you can search in the app store/google play)

Don't try to do multiple firmware updates at the same time.

If the above steps don't fix it, please write support@combustion.inc.

Firmware update stuck on "Updating: starting"?

If the firmware update "hangs", it may go a long time without completing the update (or seeming to).

This is usually an issue with the device (phone) itself.

1. Be sure whichever tool you are updating is fully charged before beginning any firmware update.

2. Restart the app and check the update status (it should say "up-to-date").

3. If that doesn't work, restart the phone/device (turn it off and on again) and check again.

4. If that doesn't help, hard reset/hard restart the phone.

Search the exact instructions for your device (hard restart + phone model in your search bar).

It's not a big deal and most of the time, this step will solve your issue permanently.

This happens most often with iPhones because of how they manage Bluetooth connections.

iPhone users hard reset: Press the Home and On/Off buttons at the same time and hold them until the Apple logo appears (about 10-15 seconds). Note: don't panic! This will not delete your settings or account stuff, but it will clear the Bluetooth cache.

Display flashing red + screeching

Overheated! Remove from heat immediately!

  • Lower sensors (below the min line) must be kept below 220ºF (105ºC).
  • Upper sensors must be kept below 600ºF (315ºC).

Using the thermometer above these temps may damage your thermometer and will void the warranty.

Bad things can happen when you exceed safe operating temps.

The "red alert" is a warning that your thermometer is in the danger zone. 

> 105ºC (sensors below the min line aka "pointy end")
> 315ºC (sensors above the min line aka "handle")

If you get a red alert:
1) Immediately remove food from heat
2) Check temps on Display + App - see if any reading is near or above the temp limits
3) Check insertion: is it at least to the min line? Was any of the lower part (below the min-line) visible (not inside the food)? 

If the lower sensors have exceeded safe operating temp, the electronics may have been damaged.

Is the CPT broadcasting? If you’re seeing temps on your display, it's probably ok. 

Follow these steps if one of the lower sensors detected an overheat:

  1. Confirm that the thermometer is still connecting to the display (temps are showing/updating)
  2. Look for any erratic changes or strange temp readings (that would indicate a damaged sensor)
  3. If you can’t connect or see erratic temps, contact support 

Otherwise the thermometer should continue to work normally   

If the higher sensors (handle end) have exceeded safe operating temp, it's possible the high heat has damaged the main seal (inside the handle).

Your thermometer will most likely still work properly, if you follow some extra precautions.

The risk is that the seal is compromised, which may allow fluid into the interior. That may eventually cause the internal electronics to short-circuit. 

Follow these precautions after a handle-overheat red alert:

  • Hand-wash only
  • Do not immerse/submerge the thermometer when cooking or washing

Damage to the seal is cumulative. The more times it happens (and the longer it stays overheated), the more likely it is that water-resistance is compromised.

Unfortunately there's no way to inspect the seals for their integrity without destroying the thermometer.

If you have more questions or need a replacement, please contact support. 

Didn’t find the info you needed? Email us.

You may find answers on the main FAQ.

You may find answers (and photos) on the official subreddit.

Please write us if you have a question or problem or would like to report an issue. (support@combustion.inc)

Your feedback is super-important, it’s a big part of how we find ways to improve the product.

Thanks for taking the time, we really appreciate it.

Happy Cooking!