Tech Article: Mastertrol® Mini-Zone™ MM-2 Zone Control Panel Installation and Operation

The Mastertrol® Mini-Zone™ -2 Zone Control Panel, Model MM-2, provides precise control over two zones in a single-stage heating and cooling system. This control panel is designed to optimize comfort by regulating the flow of conditioned air into different zones of a building, allowing for independent temperature control in each zone.

System Overview

The MM-2 Zone Control Panel manages two zones through individual thermostats. Each thermostat controls a motorized damper located in the zone's ductwork, regulating the airflow of conditioned air. The system allows for flexible configuration:

• Up to two dampers can be wired to a single zone.

• If more than two dampers are required, a Slave Damper Control Relay, Model SDCR, must be used to support additional dampers.

Zone 1 Thermostat Setup

For proper operation of Zone 1, a manual changeover subbase with "O" and "B" terminals is required. This subbase is essential for switching between heating and cooling modes:

• Cool Mode: The "O" terminal must make contact with R when the subbase is switched to cool mode.

• Heat Mode: The "B" terminal must make contact with R when the subbase is switched to heat mode.

Thermostat and Damper Operation

Once the Zone 1 subbase is set to either heating or cooling mode, the thermostats in both zones can call for their respective heating or cooling demands. The system follows these steps:

1. Thermostat Activation: When a zone thermostat detects the need for heating or cooling, it energizes its corresponding zone relay.

2. Damper Control: The relay activates the system's heating or cooling controls, opens the zone's damper, and closes the damper to any other zone that is already satisfied.

3. Zone Satisfaction: When both zone thermostats reach their desired temperatures, the heating or cooling system shuts off, and all dampers return to their normal positions.

Damper Adjustment

The normal position of each zone damper is controlled by the OPEN/CLOSED (O/C) slide switch located next to the motor terminals. This switch allows for fine-tuning the damper's position to achieve optimal airflow for each zone.

Conclusion

The Mastertrol® Mini-Zone™ MM-2 Zone Control Panel offers a flexible and efficient solution for controlling two zones in a single-stage heating and cooling system. With its ability to manage dampers based on thermostat calls and mode selection, the MM-2 enhances comfort while providing precise airflow control for each zone. For systems requiring more than two dampers, the addition of the Slave Damper Control Relay ensures seamless operation across larger systems.