Predictive Thermometer: Troubleshooting GuideUpdated 5 days ago

Having trouble with your Predictive Thermometer? You're in the right place. Most issues come down to a handful of causes (a dirty charging contact, a sleepy probe, or a WiFi band mix-up), and you can usually fix them in a couple of minutes. This guide is organized by what you're seeing, so jump to the section that matches your problem.

🩺 Start here

Just unboxed it? If this is your first time connecting, start with Brand-New Probe Won't Connect? Nearly every out-of-the-box hiccup comes down to a short list of five things.

Before anything else, these four steps clear up the majority of issues:

1. Wake the probe up. Take it *out* of the charger or Booster. It's asleep while it's charging, and powers on automatically when removed.
2. Give it a charge. A full charge takes about 25 minutes. Even 5 minutes gets you going.
3. One device at a time. When setting up or updating, turn off your *other* Combustion tools (other probes, Boosters, Displays) so they don't compete for the connection.
4. Restart the app. Fully close the Combustion app and reopen it. If you're on iPhone and still stuck, restart the phone. iPhones like to hang onto old Bluetooth connections.

Still stuck? Find your symptom below.

1. My probe won't connect to the app or Display

This is the most common thing we hear, and "not connecting" can mean a few different things. Work through these in order:

1. Is it awake? Remove it from the charger/Booster. A probe in a *powered* charger is charging; a probe in an *unpowered* charger is asleep. It needs to be out to broadcast.
2. Is it charged? A dead battery looks like a connection problem. Charge it 25 minutes and try again.
3. Clean the contact. An invisible film of cooking oil on the metal contact (the butt of the handle) can block both charging *and* connecting. Wipe it with isopropyl alcohol on a cotton swab or lint-free cloth, let it dry, then charge and reconnect. (For stubborn buildup, a *gentle* pass with steel wool on the contact is fine; it won't hurt it.)
4. Check that Bluetooth is on in your phone's settings, not just in the app.
5. Force-close and reopen the app. On iPhone, if it's still stuck, restart the phone to clear the Bluetooth cache.
6. "Last seen" is good news. If the app shows your probe as "last seen" a moment ago, the probe is alive and broadcasting. This is a *pairing* hiccup, not a dead probe. Keep the probe and phone close and retry.
7. The 96-hour reset (last resort for an unresponsive probe): leave the probe out of the charger/Booster for 96 hours. This resets it to factory firmware so you can redo the update cleanly.

If it still won't connect after a full charge, cleaning, and reset, please contact Support.

2. My probe won't charge

Nine times out of ten, this is the charging contact.

1. Clean the metal contact on the bottom of the handle with isopropyl alcohol (or a gentle scrub with steel wool). Oil builds up there invisibly over time.
2. Plug in and wait ~25 minutes. Watch the charger light: it should go from red/amber to green as it charges. No light at all usually means no contact, so reseat the probe.
3. Check your power source. Use a standard 5V USB port (a phone charger is perfect). See the ⚠️ charger warning at the bottom of this guide. The wrong charger can damage the probe.
4. Try a different cable and port to rule those out.

Still red or no light after cleaning? That might be a hardware issue; please contact Support.

3. My battery drains too fast or won't hold a charge

A few different things cause this:

• "Always On" mode uses more power. If you've turned on Always On (or are streaming over WiFi), your runtime drops. Switch to the standard power mode in app settings for the longest life.
• A probe left in an *unpowered* charger stays ready (it doesn't fully sleep). To fully power it down for storage, give it a quick plug-in to the charger (see Section 4).
• What's normal: on a full charge, a 2nd-gen probe runs up to 90 hours in cooking mode and up to 24 hours in instant-read, and holds a standby charge for up to 40 days. The WiFi Booster runs about 54 hours when actively connected over WiFi.
• WiFi Booster draining mid-cook? If your Booster sits out by the grill on weak WiFi, it can keep trying to reconnect and drain itself. Check the WiFi signal where the Booster lives (any signal-strength app works) and move it closer to a strong signal if it's weak.

4. My probe won't turn off / stays on in storage

This one surprises people. Your probe is designed to stay ready when it's sitting in an *unpowered* charger, so it may look like it's "still on."

• To power it down for storage: place it in the charger and briefly connect the charger to USB power, then unplug. That tells it to go to sleep.
• A probe left loose (not in the charger) will keep broadcasting and slowly drain. Always store it in its charger/Booster.

If it's genuinely never sleeping and draining flat within a day even when stored correctly, see "Still stuck?" at the end of this guide.

5. WiFi setup problems (Booster or Display won't join my network)

• ✅ Use the 2.4 GHz band. This is the #1 fix. Combustion WiFi tools connect to 2.4 GHz only (not 5 GHz). Many routers broadcast both under the *same* network name, so you may be joining 5 GHz without realizing it. In your router or phone, select the 2.4 GHz network specifically.
• Supported security: Open, WPA, WPA2, or WPA3 *Personal*.
• Update firmware first. Make sure the app and the WiFi tool are on the latest firmware before joining.
• Set up in the app: Settings, then WiFi Devices, then pick your tool, then Join Network, then choose your 2.4 GHz network. If it's hidden, choose "Other…" and enter it manually. You're connected when the tool shows its signal strength.

Still won't join? Forget the network in the app and re-add it, and try the general WiFi/router reset steps below.

6. Signal keeps dropping or poor range during a cook

Bluetooth is a small radio, and cooking environments are tough on it. To get the best signal:

• Add a range-extender close to the cook. Put a Booster or Display *near* the grill/smoker (outside the metal, if possible). It grabs the probe's signal and rebroadcasts it at full strength.
• Mind the obstacles. Metal (grill lids, smoker walls), water, foil, concrete, and even *people* block Bluetooth. If you wrap food in foil, keep the probe's handle outside the foil.
• Line of sight helps. Fewer obstacles between the probe and your phone/Display means better signal. Stand the Display on its kickstand.
• You won't lose data. The probe logs everything onboard, so even if you briefly drop signal, it catches right back up when you're back in range, with no interruption to your cook.

7. Overheating alarm: red flashing screen and/or screeching

This alarm means one of the probe's sensors has gone above its safe temperature. Remove your food from the heat right away, then figure out which of these two situations you're in:

A) It was inserted wrong (most common, and fixable).

The probe must be inserted at least to the minimum insertion line (about 2 inches), with the *handle end* kept out of the direct heat. If the handle was resting near the flame, or the probe was pushed all the way through the food, the upper sensors overheat.

→ Test: take the probe off the heat and let it cool to room temperature for ~10 minutes. If the alarm clears, it was an insertion issue. Just insert it correctly next time.

Temperature limits, for reference:

• Below the insertion line (the pointy end in your food): keep under 220°F (105°C)
• Above the insertion line (toward the handle): keep under 900°F (482°C) on the 2nd gen (600°F on 1st gen)

B) The alarm won't stop, or the reading is clearly wrong (likely a sensor issue).

If the alarm keeps firing *after* the probe has fully cooled, or you're seeing an extreme/stuck reading (for example, a high ambient temperature when the probe is sitting at room temperature and not even in food), that points to a sensor problem rather than something you did, so there's no need to keep troubleshooting it. Please contact Support. 

8. My temperature readings look wrong

Sometimes a "wrong" reading is actually normal physics, and sometimes it's a real fault. Here's how to tell:

Probably normal:

• Ambient reads lower than your oven/grill dial. Your oven can be off by 100°F or more, and the air right around your food is cooler than the rest of the chamber (evaporating juices cool it). Your probe is measuring the *real* temperature near the food. That's the point.
• Ambient differs from a grill-mounted gauge. They're measuring different spots. Some difference is expected.
• The "core" temp seems high early on. Insertion matters. If the tip missed the true center, give it a moment; the probe finds the lowest internal temperature automatically as the cook progresses.

Probably a fault (see "Still stuck?" at the end of this guide):

• A sensor stuck at one extreme value that won't move.
• Readings that swing wildly (for example, 178°F then suddenly 45°F with no real change).
• Two identical probes placed side by side reading very differently.
• An ambient reading that's obviously impossible for the situation (for example, hundreds of degrees at room temperature).

Quick accuracy check you can do at home: fill an insulated cup with ice, add a little cold water, and stir with the probe for ~30 seconds. All submerged sensors should read close to 32°F (0°C). If they're way off, let us know.

9. "Ready in" prediction is missing or slow to appear

The prediction needs a little time and the right setup:

• Insert to at least the minimum line (deeper is better). The prediction relies on multiple sensors being inside the food.
• Set a target temperature. The countdown only appears once you've told it what "done" means (in the app or on the Display).
• Be patient early on. The "Ready in" estimate usually appears around a third of the way into the cook and gets more accurate as you go.
• Long cooks stall. On big, slow cooks (like brisket), the internal temp naturally "stalls" for a while. The prediction won't settle until the stall breaks. That's normal; stick to your plan.

10. I can't see the surface temp or the graph

• Surface temp appears only in cooking mode. Set a target temperature and it shows up.
• Graph: in cooking mode, tap any temperature to reveal the graph. You can also toggle it from the three-dot (⋯) menu. The graph shows only while the probe is actively connected.

11. Firmware update is stuck or won't finish

Firmware updates go smoothly when only one device is powered on. If an update stalls:

1. Only the device being updated should be on. Turn off all other probes, Boosters, and Displays. For a probe update, take it out of its Booster and turn the Booster off.
2. Make sure it's charged and you're on the latest app version.
3. Wait a few minutes. Updates sometimes pause at "Starting." If it's truly stuck, fully restart the app, then restart your phone, and check again (it may already say "up to date").
4. The 96-hour reset (last resort for a probe that won't respond after an update): leave the probe out of the charger/Booster for 96 hours. This resets it to factory firmware so you can redo the update cleanly.

If it's still unresponsive after that, see "Still stuck?" at the end of this guide.

12. The probe won't seat, or pops out of the Booster

If your probe physically won't sit securely in the Booster (it wobbles, won't charge reliably, or pops out at the lightest touch), that's a known hardware issue, not something you're doing wrong.

Skip the cleaning steps and see "Still stuck?" at the end of this guide.

13. Cracked handle or physical damage

The ceramic handle is tough (it handles flare-ups, drops, and the dishwasher), but it isn't indestructible.

The most common cause of a cracked handle is quenching (see the danger box below). If your handle is cracked, the probe may still work, but its water resistance could be compromised: hand-wash only from then on. If you have concerns, see "Still stuck?" at the end of this guide.

⚠️ Things that will damage your thermometer (AVOID these!)

General WiFi / router reset

If your whole network is acting up (not just the Combustion tool):

1. Unplug your router (and modem) for 30 seconds, plug back in, wait 2-3 minutes.
2. Confirm other devices can reach the internet.
3. Keep the Combustion tool within ~30 feet of the router with clear line of sight for setup.
4. Remember: join the 2.4 GHz band (Section 5).

Still stuck? We're here to help!

If none of the steps above solved it, email our support team at [email protected] and include:

• Your order number
• Which generation you have (1st or 2nd gen) and other Combustion tools (Booster, Display, GGG)
• What you're seeing, and which steps above you've already tried
• A photo or screenshot if there's an error on screen