Dry Contact Board for HCS-2/NFS-2, 8 individual electrical contacts, each contact up to 12 Amps

What the OM-8 Does

The TrolMaster OM-8 is a dry contact relay expansion board that connects to the Hydro-X Pro (HCS-2) or Aqua-X Pro (NFS-2) controller via RJ12 and extends the system's output capacity by eight individually switched contacts. Each contact is a true dry relay — no shared neutral, no shared hot — so each channel can be wired to a separate device, circuit, or load independently of the others.

With the OM-8 in the loop, the HCS-2 or NFS-2 can trigger, stage, or sequence up to eight additional pieces of equipment — lights, exhaust fans, CO2 solenoids, irrigation pumps, supplemental HVAC, or any other switched load that fits within the 12A per-contact ceiling. The board mounts inside a standard electrical control cabinet and accepts 100–240 VAC input, making it compatible with both US 120V and 240V panels without requiring a separate transformer.

Who Needs This Board

Any commercial operator running a TrolMaster Hydro-X Pro or Aqua-X Pro system and pushing against the base controller's onboard output count should look at the OM-8. Facilities with multiple dehumidifier circuits, staged CO2 equipment, zone-specific irrigation solenoids, or multi-phase lighting sequences frequently exhaust the built-in switched outputs before they run out of sensors or modules — this board closes that gap.

The OM-8 is particularly relevant when integrating the Aqua-X Pro (NFS-2) into a nutrient dosing or drip irrigation build. In that configuration, the board can activate pumps and solenoids at the full 12A load rating, which covers most commercial-grade pump and solenoid specs without requiring an intermediate contactor or relay panel for each device. Curing and post-harvest environmental rooms that need timed or condition-triggered switching of dehumidifiers, exhaust valves, or supplemental cooling circuits are a natural fit.

Key Features

Each of the eight contacts is independently controlled and features built-in overload protection at the 12A threshold — the circuit protects both the board and connected equipment from surge events. An onboard LCD display makes setup and status confirmation straightforward without requiring the main controller touchscreen to be nearby. Each contact can also be manually forced open or closed for up to 30 minutes, which is useful during commissioning, troubleshooting, or routine maintenance without needing to reconfigure controller logic.

Connection to the controller is through a standard RJ12 cable; a 16 ft RJ12 cable is included in the package. The OM-8 is fully addressable within the TrolMaster module ecosystem, meaning outputs can be mapped to any environmental condition, trigger, or schedule that the HCS-2 or NFS-2 supports — including multi-condition logic and the built-in crop calendar. The Hydro-X Pro supports up to 50 separate control modules on a single controller, so multiple OM-8 boards can be deployed across a large facility without hitting a system ceiling.

How It Fits a Commercial Build

Installation is panel-mount: the OM-8 sits inside an electrical control cabinet, wired to the facility's existing power distribution, with the RJ12 data cable running to the HCS-2 or NFS-2. This keeps high-voltage switching contained inside the electrical enclosure — a code-sensible approach for any licensed facility subject to inspection. The 100–240 VAC input range accommodates mixed-voltage panels common in commercial builds.

Operationally, the board integrates cleanly with any existing TrolMaster Hydro-X or Aqua-X Pro setup. Because the HCS-2 is backwards-compatible with prior Hydro-X modules, facilities that have been building out their TrolMaster system incrementally can add the OM-8 without replacing other hardware. For post-harvest and curing environments where controlling multiple independent dehumidification or air exchange circuits is the primary need, the OM-8 provides the switched output density to handle it from a single controller program.