Overview and General Installation
This guide offers essential wiring details, schematics for sample applications, bills of materials featuring KMC Controls products, and other relevant information for the FlexStat. It is structured into sections covering general information, specific series (BAC-1xx63/1xxx63, BAC-1xx36/1xxx36, and BAC-1xx30), and model variations including those with CO₂ sensing and Ethernet connectivity.
Proper installation is crucial. Key considerations include mounting location, avoiding obstructions to airflow, and ensuring correct backplate compatibility to prevent damage to the unit and network circuitry. Detailed wiring practices, including conductor sizing and conduit requirements, are outlined to ensure reliable operation and prevent issues like ground loops.
Mounting Considerations
FlexStats require careful mounting to ensure accurate performance. Avoid exterior walls, large thermal masses, direct sunlight, heat sources, and drafts from diffusers or returns. Ensure proper air circulation and seal conduits to prevent air leaks.
Wiring Considerations
Thorough planning of wiring is essential due to the numerous connections required. Use adequately sized conductors for the wiring length to prevent voltage drop. Recommend using 1-inch conduit and junction boxes for all wiring. Ensure correct phasing for network and power connections on all networked controllers to avoid damage from ground loops.
Inputs and Outputs
The FlexStat supports various input devices, including active 0–12 VDC devices, passive contacts, and 10K ohm thermistors. For 4–20 mA current inputs, an external 250-ohm resistor is required to convert the current to a voltage signal. Proper configuration of input pull-up resistor switches is critical for accurate readings.
Sensor Calibration
For optimal accuracy, allow at least thirty minutes after initial power-up before calibrating the internal temperature sensor. Calibration can be performed via the FlexStat menu or through KMC software such as KMC Connect. Adjustments can be made to the calibration offset to correct discrepancies between the sensor reading and a reference thermometer.
Filter Weight (Input "Smoothing")
Filter Weight is used to smooth input value readings, reducing sensitivity to signal noise and temperature spikes. It employs a five-sample median filter followed by a first-order Infinite Impulse Response (IIR) filter. Adjusting the filter weight can improve performance in areas with fluctuating temperatures, such as those affected by door openings.
