Autopilot Digital CO2 Controller with Integrated Sensor

Control CO2 Enrichment and Exhaust From One Integrated Unit

Most CO2 controllers only handle enrichment — they trigger a generator when CO2 drops below the setpoint. The Autopilot APC8400 adds a CO2 exhaust mode: when CO2 levels rise above a safe threshold, the controller can trigger an exhaust fan to reduce levels, providing an important safety function in rooms occupied by people.

The APC8400 uses an integrated sensor built directly into the controller body, eliminating the need for a separate remote probe cable. This simplifies installation in spaces where the controller can be mounted at a representative location in the grow room.

CO2 level data is logged and can be reviewed on the controller display, providing a record of enrichment performance over time.

Key Features & Benefits

• Integrated CO2 sensor — built directly into the controller body, eliminating the need for a separate remote probe cable for installations where the controller can be placed at canopy level.
• CO2 enrichment mode — triggers a CO2 generator when levels drop below the setpoint — the standard operation mode for grow room enrichment.
• CO2 exhaust mode — triggers an exhaust fan to reduce CO2 levels when they rise above a set threshold — a critical safety function for rooms occupied by people during the grow cycle.
• CO2 level data logging — records CO2 levels for review on the controller display, allowing monitoring of enrichment performance over time.
• Simplified installation — integrated sensor means no external probe cable to route — mount the controller at a representative location and connect the generator or exhaust fan.
• Compatible with Autopilot CO2 generators — pairs directly with Autopilot LP and NG CO2 generators for automated enrichment control.

Who Should Use the Autopilot APC8400 Digital CO2 Controller

Indoor growers who want both CO2 enrichment and exhaust control from a single unit, and whose installation allows the controller to be mounted at a representative canopy-level location where the integrated sensor will provide accurate readings.

Using the CO2 Exhaust Mode

Set the CO2 exhaust threshold above your target enrichment setpoint but below levels that are unsafe for occupants (OSHA lists 5,000 ppm as the 8-hour permissible exposure limit for CO2; enrichment setpoints are typically 1,000–1,500 ppm). When triggered, the exhaust mode runs an exhaust fan until CO2 drops below the threshold.

Frequently Asked Questions

What is the difference between the APC8400 and APC8200?

The APC8400 has an integrated sensor and supports both enrichment and exhaust modes. The APC8200 uses a remote probe on a 15-foot cable and supports enrichment mode only. The APC8400 is preferred when the controller can be placed at canopy level; the APC8200 is preferred when the controller must be mounted away from the canopy.

Can the APC8400 trigger both a CO2 generator and an exhaust fan?

The APC8400 controls one output at a time — enrichment mode triggers the generator, exhaust mode triggers the fan. Configure the mode based on your primary control need.

Is the CO2 exhaust mode required for safety?

For rooms regularly occupied by people, having a CO2 exhaust mode or independent CO2 alarm is strongly recommended. At typical enrichment levels (1,000–1,500 ppm), CO2 is not acutely dangerous, but leaks or malfunctions can elevate CO2 to unsafe levels without a control mechanism.

Does the APC8400 support an external probe like the APC8200?

No — the APC8400 uses only the integrated internal sensor. If you need remote canopy-level probe placement, use the APC8200 with the APC8210 extension cable.