S151 – I/O Expander, Permeate Divert & Alarm RO Controller

Expanded Relay Control for Permeate Divert, Remote Alarm & Tank-Low Shutoff

The S151 adds an I/O expander to this Series 150 microprocessor RO controller platform, giving it two additional relay outputs beyond the base configuration: one for permeate divert or remote alarm output, and a second auxiliary relay with a low-tank input. That makes it a strong fit for commercial and industrial reverse osmosis systems that need to automatically divert off-spec permeate, trigger an external alarm, or shut down on a low-tank condition, without stepping up to a full building-management integration.

At its core, the controller runs the RO system through three base relay outputs and four dry contact inputs, managed from a 2-line by 20-character backlit LCD display that shows system status, water quality, operating hours, and temperature in real time. It can directly drive a high-pressure pump up to 1 HP single phase, along with the inlet solenoid valve and automatic flush valve, while dry contact inputs track storage tank level, low and high feed pressure, and a pretreatment lockout signal — all managed with time delays to keep the system operating correctly. Housed in a hinged NEMA 4X enclosure, it's built to hold up in demanding installation environments.

With the I/O expander built in, the S151 gives you two extra points of control beyond the base three relays: a permeate divert or remote alarm relay, plus an auxiliary relay wired to a low-tank input for automatic shutoff protection. If your application also needs independent feed-water quality monitoring alongside this expanded relay control, the S153 configuration builds on this same I/O setup with a second TDS board and sensor included.

Because this controller is built to order for the specific application it's going into, a few options need to be specified at the time of purchase rather than being fixed in advance.

Core Specifications

S151-Specific Feature (Included as Standard)

Specify at Time of Order

Let us know your required configuration when ordering, or contact us for help selecting the right options for your system.

Why Choose the Series 150 Pre-Assembled Controller

• UL/cUL Certification Available: Select the UL-labeled voltage option at checkout to get a pre-certified control system, without the cost and lead time of certifying a custom-wired panel yourself. This helps satisfy requirements from insurance adjusters and building inspectors and removes the legal uncertainty often associated with custom-wired, uncertified control boxes.
• Engineering Efficiency & Labor Savings: Eliminate 2–4 hours of complex labor, including sourcing parts, drilling enclosures, mounting hardware, and manual wiring. This unit arrives ready to install, allowing your team to focus on system deployment rather than tedious electrical assembly.
• Turnkey "Plug-and-Play" Reliability: Avoid the risk of installation errors and complex onsite troubleshooting. The Series 150 offers a pre-tested, integrated ecosystem where the TDS sensor, relay logic, and flush timing are verified to function together seamlessly right out of the box.
• Unified Warranty & Support: Simplify your maintenance workflow with a single point of contact. Avoid the diagnostic burden of troubleshooting individual components; with this integrated unit, you have one manufacturer to contact for support and warranty coverage, significantly reducing system downtime.
• Professional Uniformity & Scalability: Ideal for operations that require consistency. The standardized wiring harness and rugged NEMA 4X professional finish ensure that every installation looks identical and remains easy to service, providing a polished, high-end appearance that reflects the quality of your entire filtration system.