Refrigerant, Toxic & Combustible Gas Controller and Networkable Sensors

The 301EM-20 acts as a controller for up to 20 remote sensors and suits a variety of gas detection system solutions for Mechanical Rooms.

Particularly configured to meet ASHRAE 15, B-52 and International Mechanical Code requirements, the 301EM-20 is commonly used to optimize gas detection in mechanical and chiller rooms. A full complement of sensors (including toxic, oxygen, combustible gases and a full line of refrigerant sensors), horns, strobes and remote panels provide added flexibility to suit a variety of gas detection system solutions.

User Friendly

• Easy to read LCD display

• Auto‑diagnostic capabilities

Economical Solution

• Cost-effective answer for installation in Mechanical Rooms locations

Flexible Operation

• Able to operate with up to 20 remote sensors at a time

• Various types of sensors available to simultaneously detect a range of different Refrigerant, Toxic and Combustible gases

• Robust and reliable RS-485 Modbus communication

Output Adaptability

• Three 24 Vdc alarm outputs and four 4-20 mA outputs

Safety Measures

• Four fully programmable relays

• Three alarm levels with built-in visual indicators and audible alarm

Beneficial Options

• Convenient stand-alone or network operation


• Mechanical Rooms


• Intertek Classified (301IRFS) Listed (301EM) to: UL 61010-1; and CSA C22.2 No. 61010-1-04