Silent Knight SK-RELAY Addressable Relay Module

The Silent Knight SK-RELAY is an intelligent addressable relay control module designed to provide programmable switching of auxiliary equipment through compatible Honeywell Silent Knight fire alarm control panels (FACPs). Featuring two electrically isolated Form C relay contacts operating as a double-pole, double-throw (DPDT) switch, the SK-RELAY allows a fire alarm system to activate or deactivate connected equipment in response to programmed alarm, supervisory, or control events. The module operates on a 15-32 VDC signaling line circuit (SLC) and incorporates rotary address switches, SEMS screw terminals, and a panel-controlled LED that flashes green during normal operation and illuminates solid red when activated. Its relay contacts support switching loads up to 3 amps at 30 VDC resistive, with additional ratings for compatible AC and inductive applications. Measuring 4.675 inches high by 4.275 inches wide by 1.4 inches deep, the SK-RELAY mounts to a standard 4-inch square electrical box with a minimum depth of 2-1/8 inches. Designed for commercial and institutional fire protection systems, the module supports applications such as HVAC shutdown, equipment control, and auxiliary alarm signaling. The SK-RELAY is UL listed and requires a compatible Silent Knight addressable fire alarm control panel for operation.

Silent Knight SK-RELAY Intelligent Addressable Fire Alarm Relay Control Module

The Silent Knight SK-RELAY Intelligent Relay Module provides programmable auxiliary equipment control for commercial and institutional fire alarm systems using compatible Honeywell Silent Knight addressable fire alarm control panels. Designed for integration with an intelligent two-wire signaling line circuit (SLC), the SK-RELAY enables a connected fire alarm panel to operate external electrical contacts according to programmed system events and control logic. The module contains two electrically isolated Form C relay contact sets configured as a double-pole, double-throw (DPDT) switch, allowing two separate circuits to change state simultaneously when the module is activated. Each contact set provides normally open, normally closed, and common connections for integration with compatible equipment. This functionality supports applications involving HVAC shutdown interfaces, ventilation controls, auxiliary alarm signaling, equipment shutdown, and building automation integration. Unlike conventional hardwired relays that require a dedicated control output from the fire alarm panel, the SK-RELAY receives commands through its assigned address on the compatible Silent Knight SLC. Its programmable operation allows system designers to associate relay activation with specific alarm conditions, detection zones, and approved control sequences.

The SK-RELAY incorporates two isolated SPDT Form C contacts that operate together as a DPDT switching arrangement, supporting separate normally open and normally closed control circuits. The manufacturer specifies a maximum contact rating of 3 amps at 30 VDC for non-coded resistive loads and 2 amps at 30 VDC for coded resistive loads. Additional published ratings include 0.9 amps at 125 VDC resistive, 0.5 amps at 125 VAC with a 0.75 power factor, and 0.3 amps at 125 VAC with a 0.35 power factor for qualifying applications. The module operates from the fire alarm signaling line circuit at 15-32 VDC, with an average operating current of approximately 230 microamps during direct polling or 255 microamps during group polling. Maximum current consumption reaches 6.5 mA when the status LED is illuminated. Its compact assembly measures 4.675 inches high by 4.275 inches wide by 1.4 inches deep (119 x 108 x 36 mm) and mounts to a standard 4-inch square electrical box with a minimum depth of 2-1/8 inches. Environmental operating specifications include a temperature range of 32 F to 120 F (0 C to 49 C) and relative humidity of 10-93% non-condensing. The SK-RELAY is UL listed for applicable fire alarm system applications when installed with approved compatible equipment.

For addressable fire alarm control applications, the Silent Knight SK-RELAY provides programmable relay activation through the fire alarm control panel's signaling line circuit. Each module is assigned a unique device address using its built-in rotary switches, allowing the panel to communicate with the relay and operate its contacts according to the programmed cause-and-effect configuration. The module features a panel-controlled bi-color LED that flashes green during normal communication and illuminates solid red when the relay is activated, providing visual indication of device status during inspection and troubleshooting. Manufacturer-documented compatible legacy control panels include the Silent Knight 5700, 5808, 5820XL, 5820XL-EVS, 6700, 6808, 6820, and 6820EVS, while newer manufacturer documentation identifies compatibility with the 6808U, 6820U, and 6820UEVS Ultra Series. Compatibility must be verified against the installed panel's supported device list and firmware requirements. The relay's independent contact sets can interface with appropriately rated HVAC controls, external notification equipment, building automation inputs, and other auxiliary circuits. The SK-RELAY does not supervise the electrical circuits connected to its relay contacts, so any required external circuit supervision must be provided through separately approved equipment or system arrangements. It also does not supply power directly to connected loads; an appropriate external power source is required where electrical power is necessary for the controlled equipment.

Installation of the Silent Knight SK-RELAY addressable relay control module requires a compatible Silent Knight SLC connection, proper device addressing, and wiring of the controlled circuits to the designated relay terminals. The unit mounts directly to a 4-inch square electrical box with a minimum depth of 2-1/8 inches, while the optional System Sensor SMB500 surface-mount box supports installations where a recessed electrical box is unavailable. The manufacturer's installation instructions also identify mounting compatibility with the appropriate DNR duct detector housing for approved configurations. The module incorporates SEMS screw terminals for SLC and relay connections, rotary address switches for local device identification, and a removable cover plate with a visible status LED. When relay circuits include non-power-limited wiring, the optional CB500 module barrier may be required to maintain the separation specified by the manufacturer. Installation procedures include setting the device address, connecting the SLC conductors, terminating the normally open, normally closed, and common relay connections, and configuring the relay's programmed activation conditions through the fire alarm control panel. During commissioning, technicians verify normal communication, programmed relay operation, contact switching, and the response of connected equipment. The manufacturer also requires confirmation that relay contacts are in their intended standby state before connecting controlled circuits. The SK-RELAY is distinct from a supervised notification appliance control module because its Form C contacts provide switching functionality without monitoring the downstream circuit for faults. Combining two isolated relay contact sets, intelligent SLC communication, programmable activation, low-current operation, and compact electrical box mounting, the Silent Knight SK-RELAY provides an auxiliary control interface for compatible commercial fire detection and life-safety systems.