What is the approximate discharge pressure range in heating mode for an indoor SCFM of 1250 at an outdoor temperature of 20 degrees?

To determine the approximate discharge pressure range in heating mode for an air-to-air heat pump, it's essential to consider factors such as the system's design, operating conditions, and the specific application of heat pumps.

For an indoor airflow of 1250 SCFM (Standard Cubic Feet per Minute) and an outdoor temperature of 20 degrees Fahrenheit, the refrigerant must be compressed efficiently to provide adequate heating. In heating mode, the discharge pressure is significantly influenced by the outdoor ambient temperature and the heat pump design. Operating at an outdoor temperature of 20 degrees typically results in a lower evaporating temperature and thus requires a higher discharge pressure to maintain heating efficiency.

The correct range of 260 to 280 psig reflects typical performance metrics for residential heat pumps under these conditions, ensuring effective heat transfer and maintaining system efficiency. This pressure range indicates that the system can balance the load while functioning effectively in colder outdoor temperatures.

Higher or lower pressure ranges, while theoretically possible, would either indicate insufficient performance in heating mode or the heat pump operating inefficiently, causing potential issues like compressor wear or inadequate heating to the indoor space. Therefore, the identified pressure range aligns closely with the expected operational norms for heat pumps functioning in moderate heating conditions.