Q979C1036 HONEYWELL

The Honeywell Q979C1036 is a Remote Sensor and Setpoint Module that is typically used as an accessory in conjunction with a larger temperature controller, such as the discontinued Honeywell T8078C Modulating Controller, within heating, ventilation, and air conditioning (HVAC) systems. It functions as a wall unit that provides a remote user interface for sensing the room temperature and allowing occupants to adjust the desired temperature setpoint.

Product Specifications

• Accessory Type: Remote Sensor and Setpoint Module/Wall Unit

• Function: Provides remote sensing of room temperature and allows for $\pm 5 \text{ K}$ remote setpoint adjustment.

• Compatibility: Designed to be used with specific Honeywell controllers that accept a resistance input for remote setpoint and temperature sensing, such as the T8078C Modulating Controller.

• Control Output: The module itself does not directly control a heating or cooling system; it sends signals (changes in resistance or voltage, depending on the controller's requirements) back to the main controller.

• Power: Typically operates on a $24 \text{ Vac}$ low-voltage power supply, consistent with standard commercial HVAC controls.

• Control Type: Non-programmable at the unit level; it acts as an input device for a central modulating or proportional temperature controller.

• Physical Description: A small, square wall-mounted unit, often white or similar neutral color, featuring a dial or interface for setpoint adjustment.

• Weight: Approximately $0.66 \text{ lbs}$ (Net Weight is an estimate based on surplus listings).

Product Advantages

• Centralized Control Flexibility: It allows the main controller to be mounted in an equipment room or panel for security and protection, while providing a user-friendly and aesthetically pleasing interface in the occupied space.

• Accurate Remote Sensing: Placing the sensor element directly in the controlled room ensures that the temperature being measured is representative of the actual conditions experienced by the occupants.

• Setback/Setup Capability: When paired with a compatible controller, the remote setpoint adjustment capability can be used to easily implement temporary comfort adjustments or contribute to energy savings by allowing for quick setup/setback adjustments via the main controller's input.

• Ease of Use: The wall unit typically features a simple dial or button interface, making it intuitive for occupants to make minor adjustments to their desired temperature.

Important Considerations (Precautions)

• Controller Compatibility: The Q979C1036 is an accessory and must be used with a compatible main temperature or process controller (e.g., T8078C). It will not function as a standalone thermostat.

• Wiring Integrity: As a low-voltage analog input device, the accuracy of the temperature sensing and setpoint signal depends on proper wiring with no resistance or interference along the connection run between the module and the main controller.

• Discontinued Status: The Q979C1036 is a legacy product, and its primary associated controller (T8078C) is also discontinued. Users should verify the availability of replacement parts and consider migration to current Honeywell/Resideo control platforms for new installations.

• Installation Location: The module should be mounted on an interior wall, away from drafts, heat sources (like sunlight or appliances), and air discharge vents to ensure the remote sensor provides an accurate reading of the ambient room temperature.

Product Applications

The Q979C1036 module is primarily used in commercial and institutional building management systems (BMS) where centralized, modulating control of room temperature is required.

• Hydronic Heating Systems: Used in conjunction with modulating controllers that operate zone valves (e.g., proportional control of two-pipe heating systems) to regulate the flow of hot water or steam to terminal units like fan coils or radiators.

• Airside Control: In Variable Air Volume (VAV) or other air handling systems where the controller modulates a damper actuator to maintain space temperature.

• Zone Temperature Control: Providing local temperature feedback and setpoint adjustment in individual zones, offices, or classrooms within a larger building where a central controller manages the main HVAC equipment.

• Process Temperature Monitoring (Limited): It can be used as a remote sensing element for any process control application that uses a compatible Honeywell controller and requires an adjustable temperature feedback mechanism.