my temperature swings are huge, like 50 degrees over and under my set point on the daniel boone.

Diagnosis

Temperature swings of 50 degrees or more on the Daniel Boone Prime Plus usually indicate a failure in the PID (Proportional-Integral-Derivative) control loop. This happens when the RTD (Resistance Temperature Detector) probe provides inaccurate readings or when the fuel delivery is inconsistent, causing the controller to "over-correct." Instead of maintaining a steady state, the grill dumps too many pellets, overshoots the target, and then starves the fire to compensate, creating a volatile temperature seesaw. This is most frequently caused by carbon buildup (creosote) on the RTD probe tip. Even a thin layer of blackened soot acts as an insulator, delaying the signal to the controller; by the time the sensor registers the heat, the fire is already too hot. Alternatively, "pellet bridging" or ash accumulation in the firepot prevents the pellets from igniting uniformly, leading to sudden bursts of combustion when a clump finally catches fire. You can confirm this by observing the pellet level in the pot; if you see "mountains" of unburnt pellets that suddenly vanish into a flash of heat, you have a fuel-feed issue.

How to Fix It

To stabilize your temperature swings, follow this deep-cleaning and calibration sequence:

1. Clean the RTD Probe: Locate the temperature probe inside the grill. Use a soft brass brush or a fine-grit scouring pad to gently remove all carbon buildup from the metal tip. Do not use heavy abrasives or chemicals, as scratching the sensor housing can cause permanent calibration drift.
2. Deep Clean the Firepot: Turn off the grill and allow it to cool completely. Remove the grill grates and the drip tray. Use a shop vacuum to remove every speck of ash from the burn pot and the surrounding combustion chamber. Ensure the air intake holes at the bottom of the pot are completely clear of debris.
3. Verify Pellet Quality: Empty your current hopper and check for "fines" (sawdust). If your pellets are crumbling or have a high dust content, they will burn inconsistently. Refill with a high-density, food-grade hardwood pellet with a consistent 6mm diameter.
4. Perform a Feed Test: With the grill off, use the "Feed" button to manually run the auger. Observe the pellets dropping into the pot. They should fall in a consistent, steady stream without hesitation or "clumping" at the exit point of the auger tube.
5. Calibrate the Offset: Once the grill is stabilized, if you notice a consistent 5-10 degree difference between the controller and a handheld probe, go to the settings menu and adjust the temperature offset to align the two.

If That Didn't Work

• Check for Air Leaks: Inspect the lid gasket and the hopper lid. If cold air is leaking into the combustion chamber through gaps in the seals, the PID controller will struggle to maintain heat, leading to erratic swings. Replace any worn seals or use high-temp food-grade foil to block gaps.
• Inspect the Induction Fan: Ensure the fan at the bottom of the grill is spinning freely and isn't obstructed by ash or a foreign object. If the fan is struggling to push air, the fire will smolder and then flare up violently once oxygen finally penetrates the ash bed.
• Test the RTD Wiring: Check the wiring harness leading from the probe to the control board. If the wire is frayed or pinched, it can cause intermittent signal loss, which the controller interprets as a sudden drop in temperature, triggering an unnecessary burst of pellets.
• Update the Firmware: Ensure your Prime Plus is connected to Wi-Fi and running the latest firmware version. Manufacturer updates often include refined PID algorithms specifically designed to smooth out temperature oscillations.

Heads Up

• Avoid "Over-Tuning": Do not constantly change the temperature set point during a cook; give the PID controller at least 20 minutes to stabilize after any adjustment.
• Ash Management: Vacuum the firepot every 2-3 cooks. Accumulated ash restricts airflow, which is the primary cause of "temperature spikes" on the Daniel Boone series.
• Pellet Storage: Store your pellets in a sealed, airtight container. Damp pellets swell and create friction in the auger, leading to inconsistent fuel delivery and erratic heat.
• Probe Placement: Never move the RTD probe to a custom location. The probe is positioned specifically to balance the ambient air temperature with the heat source; moving it will cause the grill to over-fire or under-fire.