LCN 7981ES Single Control Box w/air pump - ES Relay

The LCN 7981ES is the single-door control box with built-in air compressor and electric strike relay for the LCN 4820 pneumatic automatic door operator system. It does three things in one housing: pressurizes the pneumatic system that opens the door, accepts the activation signal from a push plate or wireless actuator, and signals the electric strike relay to release the door latch at the same time the door swings open.

Without the ES relay (the standard 7981), activating the pneumatic door operator swings the door open physically, but if there's an electric strike holding the latch, the strike must be separately controlled or the door pushes against a locked latch. The ES relay eliminates that problem. When the control box activates, both the pneumatic operator and the electric strike relay fire together. The door swings. The strike releases. The latch clears. One activation, clean operation.

This box handles one door leaf. For two doors, or for a vestibule with sequential operation, the 7982 Series (dual circuit) is the correct specification. For a system without an electric strike, the standard 7981 without the ES relay does the same job at lower cost. For all electric strike hardware and access control accessories, browse our electric strikes catalog.

The ES Relay Does Not Power the Strike

This is the most important technical note on this page. The 7981ES includes the relay that controls the electric strike signal, but it does not supply electrical power to the strike. The electric strike needs its own separate power source, typically 12VDC or 24VDC from a dedicated power supply.

The relay works like a light switch that flips the moment the door starts to open. When someone presses the activation button, the control box fires two things at the same time: the air burst that swings the door, and the relay that signals the electric strike to release. You don't have to trigger the strike separately. You don't need two buttons. One press handles both. The relay has one set of Normally Open (N.O.) contacts and one set of Normally Closed (N.C.) contacts on an isolated SPDT configuration. This gives the installer flexibility: if the electric strike is fail-safe (unlocks when power is removed), wire to the N.C. contacts. If the strike is fail-secure (unlocks when power is applied), wire to the N.O. contacts. In both cases, the 7981ES provides the switching signal; the installer provides the power supply for the strike.

Wired or Wireless Activation

The 7981ES accepts Normally Open (N.O.) inputs from two source types. Hardwired actuators: standard push plates, ADA push pads, or access control signal outputs wired directly to the control box. RF wireless: compatible LCN wireless actuator/receiver combinations that transmit the activation signal without a wired run from the activation button to the control box. The wireless option is useful on retrofit installations where running wiring to every ADA push pad location is impractical or cost-prohibitive.

LCN 7981ES Specifications

• SKU: 7981ES

• Also known as: LCN 7981ES, ES7981, 7981 ES relay, LCN 7981 ES, 7981 electric strike control box, 7981 single control box air pump

• Series: LCN 7980

• Type: Single circuit pneumatic control box with built-in air compressor and electric strike relay

• Circuits: 1 (single door leaf)

• Air pump: Built-in; no separate compressor required

• ES relay: SPDT isolated relay; 1 N.O. contact, 1 N.C. contact; controls electric strike signal

• Electric strike power: Not provided by control box; requires separate power supply

• Activation input: Normally Open (N.O.) hardwired or RF wireless actuator/receiver

• Compatible operator: LCN 4822 Pneumatic Auto Equalizer Power Operator

• Resources: LCN 7980 Catalog Information in Resources section

7981ES vs Other Control Box Variants

7981 = single door, built-in air pump, no electric strike relay. 7981ES (this product) = single door, built-in air pump, with SPDT ES relay. 7982 = dual door, built-in air pump, no ES relay. 7982ES = dual door, built-in air pump, with SPDT ES relay. 7982S = dual door, built-in air pump, with sequential timer for vestibule operation.