If you’re looking for consistent information about ducted air conditioners, here’s a quick guide that could be useful for you as an air conditioning technician: Key Constants for Duct Air Conditioners 1. Airflow Standards • Standard airflow is approximately 400 CFM (Cubic Feet per Minute) per ton of cooling capacity. • This is essential for proper duct design and balancing. 2. Static Pressure • Maintain static pressure between 0.1 to 0.2 inches of water column (inWC) in the duct system for efficient airflow. 3. Temperature Differential (Delta T) • Ideal temperature drop across the evaporator coil: 16°C to 20°C (28°F to 36°F). • This ensures optimal cooling and efficiency. 4. Refrigerant Pressure (Approximate Ranges) • Suction Pressure (Low-Side): 60–75 psi (depending on refrigerant type and ambient temperature). • Discharge Pressure (High-Side): 200–250 psi for most residential systems. 5. Duct Sizing • Use the Manual D or Equal Friction Method for sizing. Oversized ducts cause low air velocity, and undersized ducts lead to high static pressure. • Ensure proper sealing to avoid leakage (less than 5% leakage is ideal). 6. Insulation • Use duct insulation with an R-value of 6 or higher for energy efficiency and to prevent condensation. 7. Return Air Size • Return ducts should be sized to handle 100% of the supply airflow to maintain balance in the system. Best Practices for Duct Air Conditioner Installation • Leak Testing: Always check ducts for leaks using a blower door or duct pressurization test. • Proper Slope: Ensure ducts are sloped correctly to prevent water buildup in case of condensation. • Regular Maintenance: Clean air filters and inspect ducts for blockages during routine maintenance. Let me know if you need specific technical calculations or tools for ductwork!