How the controller and temperature sensor decide when to feed

The controller is the grill's brain, and the temperature sensor is its only sense of how hot things are. Most of what looks odd about the display comes from how those two work.

The sensor reports, the controller acts

Many grills use a feedback loop. The sensor measures the grill temperature and sends the information to the controller, which starts or halts the auger when the grill goes above or below a set threshold.¹

The sensor is often called an RTD, short for resistance temperature detector. It's a probe that senses the temperature and relays it to the control board so you can read it.²

That's all the controller knows. It doesn't see your food, your weather or your fire. It sees one number from one spot, and it responds to that.

Three kinds of controller

Older grills used a simple selector with settings like low, medium and high. Each setting roughly matched a temperature range, using a fixed, predefined duty cycle.¹ A duty cycle here means the pattern of auger running and resting. The page on the feed cycle explains it.

Digital controllers use the sensor loop described above.

A PID controller goes further. PID is short for a type of control math. It fine-tunes the rate pellets are fed by learning how long and how much fuel it takes to raise the temperature under current conditions.¹ Those adjustments continue for hours, even after the programmed temperature is reached.¹

So a grill with a smarter controller may still swing. It just corrects itself in a more refined way.

Why your thermometer disagrees

The display shows what the sensor sees, wherever that sensor sits. Your own thermometer sits somewhere else, maybe at the grate, maybe near the food. Two probes in two places can read differently because they're measuring different air.

None of the saved sources gives a standard size for that gap, so don't treat any single number as the rule. If the difference seems large, your manual is the place to look. The fault-finding page has more: sensor, fan and igniter.

One thing a source does say plainly: if you neglect to clean the probe, it could get dirty and start causing the grill's temperatures to fluctuate.² The same source calls cleaning it regularly a way to get an accurate reading.² Follow your manual's cleaning and safety steps.

Don't keep nudging the dial

It's tempting to adjust the setpoint when the display looks off. One maker warns against it. If you change the temperature too often during a cook, that can cause issues with maintaining temperature.³ Its advice is to give time between changes so the grill can keep up.³

Using this in practice

• Read the display as the sensor's view, not the whole truth of the chamber.
• Let a change settle before making another.
• Keep the probe clean, following the manual.
• If you want a second opinion on heat, use a separate thermometer and note where it sits.

Sensor trouble that goes past cleaning belongs with the maker. Don't swap parts or open the control box yourself unless the manual says that's something owners can do.