Three-Zone Expandable Switching Relay, 120VAC

Argo ARM3P Three-Zone Switching Relay – Expandable Multi-Zone Control for Hydronic Heating

The Argo ARM3P is a three-zone switching relay panel engineered for control of hot water heating zones in hydronic systems. Designed to operate on a 120VAC input, this panel integrates circulator management with boiler control for up to three zones, with expansion capability up to 15 zones using optional add-on modules.

This unit includes a built-in 30 VA transformer, auto-reset electronic fuse protection, relay diagnostic indicators, and a 5-second boiler shut-off delay to prevent short cycling. Its double-sided printed circuit board ensures signal integrity and is factory-tested for consistent field performance.

Core Features

• Three-Zone Control: Independently manages up to three circulators or zone valves
• Expandable to 15 Zones: Supports additional heating zones using plug-in ARMEXP modules
• Integrated Transformer: 30 VA transformer supplies 24 VAC thermostat control voltage
• Relay Load Capacity: Supports loads up to 1/3 horsepower
• Auto Reset Protection: Built-in electronic fuse protection with automatic reset
• Priority Timer: Automatically cycles inactive zones every 30 minutes to avoid stagnation
• Relay Diagnostics: Individual zone status LEDs accessible through the panel cover

Technical Specifications

• Model: ARM3P
• Voltage Input: 120 VAC
• Thermostat Voltage: 24 VAC (from integrated transformer)
• Transformer Rating: 30 VA
• Frequency: 60 Hz
• Amperage Draw: 7.2 A
• Relay Load Rating: 1/3 hp motor
• Boiler Shut-Off Delay: 5 seconds

Installation Guidance

The ARM3P is designed for surface-mount installation in mechanical rooms. Clearly labeled terminal blocks simplify thermostat, circulator, and boiler wiring. All field work should be completed by licensed HVAC or electrical professionals in compliance with national and local code requirements.

Application Overview

This relay panel is suited for multi-zone residential or light commercial systems requiring discrete zone control with integrated priority and diagnostics. Its modular design accommodates future zone expansion without requiring control board replacement.

Additional Features

• Zone Priority with Timer Override: Maintains zone heating distribution even during low-demand cycles
• Double-Sided Circuit Board: Factory-tested for circuit integrity and reliability
• Expansion Terminals: Allows connection of ARMEXP modules for additional zones
• Isolated ZC/ZR Switching: Provides separate contacts for boiler aquastat control

Professional Use Considerations

The Argo ARM3P provides a field-proven control solution for managing multiple heating zones with reliable electrical isolation, system protection, and expandability. Preconfigured settings and diagnostic indicators help reduce setup time and service callbacks on the jobsite.