TrolMaster CO2 Alarm Station (blue light) plus LED display indicator w/cable set

The TrolMaster AS-4 CO2 Alarm Station is a wall-mounted alert unit designed to keep personnel informed of CO2 levels outside the grow space. It pairs a blue light LED display indicator with an LCD digital ppm readout and an audible alarm, triggering whenever CO2 concentrations exceed the threshold set in your TrolMaster main controller. The package includes a 16 ft RJ12 cable for direct connection to the controller network.

TrolMaster AS-4 CO2 Alarm Station Specifications

The AS-4 is part of TrolMaster’s modular CO2 monitoring ecosystem. It connects via RJ12 cable to TrolMaster controllers and sensor modules, displaying real-time CO2 ppm readings on its built-in LCD screen while providing visual and audible alerts when programmed thresholds are crossed.

Specification	Value
Model	AS-4 (Alarm Station 4)
Alarm Indicator Color	Blue LED
Display Type	LCD digital ppm level readout
Alarm Types	Audible alarm + blinking blue LED
Sensor Link Options	Low-level sensor, high-level sensor, or both (redundancy mode)
Operating Temperature	32–122°F (0–50°C)
Operating Humidity	<90% RH
Connection Interface	RJ12
Included Cable Length	16 ft (approx. 4.9 m)
Package Contents	1x AS-4 Alarm Station, 1x 16 ft RJ12 cable
Brand	TrolMaster

Why Choose the TrolMaster AS-4 CO2 Alarm Station

CO2 enrichment is common in sealed and semi-sealed grow rooms, but elevated CO2 concentrations pose a serious safety risk to anyone entering the space. The AS-4 is designed to address this directly: it mounts outside the monitored area so staff can see the current ppm reading and check whether an alarm condition exists before entering.

The blue LED indicator provides an at-a-glance status visible from a distance, even in a busy facility. When the CO2 level exceeds the threshold programmed in the TrolMaster main controller, the AS-4 simultaneously triggers an audible alarm and blinks the blue LED, making it difficult to miss. The LCD digital ppm display shows the actual measured concentration, not just a binary safe/unsafe signal, which allows growers to assess conditions precisely.

The AS-4 can connect to either the low-level CO2 sensor, the high-level CO2 sensor, or both. Linking to both sensors enables full redundancy: if either sensor detects an out-of-range condition, the alarm station responds. This is useful in large spaces where stratification may cause CO2 levels to differ at different heights.

• Mounts outside the monitored space — personnel can read CO2 ppm before entering, reducing exposure risk.
• Dual alert output — audible alarm and blinking blue LED operate simultaneously when threshold is exceeded.
• Live LCD ppm display — shows the actual concentration, not just a warning light, enabling informed decisions.
• Flexible sensor linking — connects to low-level sensor, high-level sensor, or both for redundant coverage.
• Integrates with TrolMaster controllers — threshold is set in the main controller, keeping all alarm parameters in one system.

Best Uses for the TrolMaster AS-4 CO2 Alarm Station

The AS-4 is appropriate wherever CO2 enrichment is actively used and personnel safety monitoring is required. Its exterior-mount design makes it particularly well-suited to enclosed or sealed environments.

• Sealed grow rooms with CO2 injection — place the AS-4 outside the main door so growers can confirm ppm is within safe entry range before opening the room.
• Commercial cultivation facilities — in multi-room operations, an AS-4 at each room entry point provides consistent, visible safety signaling across the facility without requiring separate alarm systems.
• Rooms using TrolMaster CO2 controllers — the AS-4 integrates directly with TrolMaster’s Hydro-X and Pro series controllers, reading the threshold already configured in the controller rather than requiring separate programming.
• Environments requiring redundant CO2 monitoring — by linking to both the low-level and high-level sensors simultaneously, the AS-4 can confirm safe conditions at multiple measurement points within the same space.
• Compliance-conscious operations — facilities subject to workplace safety regulations around CO2 use can use the AS-4 as part of a documented alerting and entry-control procedure.

Compatibility

The AS-4 is designed to work within the TrolMaster ecosystem. It connects to TrolMaster main controllers via the included 16 ft RJ12 cable and receives threshold data from the controller’s configured CO2 alarm settings. It is compatible with TrolMaster low-level and high-level CO2 sensors, and can be linked to one or both simultaneously.

Operating temperature range is 32–122°F (0–50°C) with relative humidity up to 90% RH, which covers standard indoor cultivation environments. The RJ12 connection is a standard six-position connector used throughout the TrolMaster accessory line.

If you are also managing air circulation in your climate environment, the Active Air HD 18-inch pedestal fan pairs well with CO2 distribution in sealed rooms. For broader environmental control and monitoring, the Autopilot PX2 advanced lighting controller is another climate-layer tool used in similar setups.

If your TrolMaster controller is located farther than 16 ft from the intended mounting point, additional RJ12 extension cables may be required. Consult TrolMaster’s accessory documentation for maximum cable run recommendations.

Usage Guidelines

The AS-4 functions as a passive monitoring and alarm output device. Once installed and connected, it continuously displays the current CO2 ppm reading on its LCD screen. No periodic recalibration of the alarm station itself is required — the alarm threshold is managed in the TrolMaster main controller.

Alarm threshold: Set the CO2 alarm level in your TrolMaster main controller according to your facility’s safety policy and local regulations. Once the controller detects that the connected sensor(s) report a value above the configured threshold, it signals the AS-4 to activate its audible alarm and blink the blue LED indicator.

Entry procedure: Before entering a CO2-enriched space, check the AS-4 display for the current ppm reading. If the blue LED is blinking or the audible alarm is active, do not enter until ventilation has reduced CO2 to a safe level. A common guideline is to wait until readings fall below 1,000 ppm before unprotected entry, though your facility’s specific safety procedures should govern this decision.

Redundancy mode: When the AS-4 is linked to both the low-level and high-level CO2 sensors, it will alarm if either sensor triggers. This is the recommended configuration for rooms where CO2 may stratify between floor and canopy height.

How to Install the TrolMaster AS-4

The AS-4 is wall-mounted outside the monitored space. Installation is straightforward and does not require electrical wiring — power and data both travel over the RJ12 cable from the TrolMaster controller.

1. Choose a mounting location outside the grow room door, at eye level and in a position clearly visible to anyone approaching the entry point.
2. Mount the alarm station to the wall using the mounting hardware appropriate for your wall type. The unit should be secure and level.
3. Run the 16 ft RJ12 cable from the AS-4 through or around the door frame to the TrolMaster main controller inside the room. Ensure the cable is routed so it does not interfere with door operation.
4. Connect the RJ12 cable to the appropriate alarm station port on your TrolMaster controller. Refer to your controller’s wiring diagram to confirm the correct port — TrolMaster controllers label sensor and accessory ports clearly.
5. Configure the CO2 alarm threshold in your TrolMaster main controller’s settings menu. Set the upper limit appropriate for your facility’s safety requirements.
6. Link the AS-4 to the appropriate sensor(s) — either the low-level CO2 sensor, the high-level CO2 sensor, or both — as supported by your controller configuration.
7. Verify operation by observing the LCD display for a live ppm reading. Temporarily raise the alarm threshold below the current ppm reading to confirm the audible alarm and blue LED blinking activate correctly, then restore the threshold to its intended value.

Sources & Further Reading