In heating mode, what is the approximate discharge pressure range for a system with 1250 SCFM at an outdoor temperature of 15 degrees?

In heating mode, the discharge pressure of a heat pump system is influenced by various factors, including the refrigerant type, system design, and outdoor temperatures. For a system operating at 1250 Standard Cubic Feet per Minute (SCFM) at a lower outdoor temperature like 15 degrees Fahrenheit, the discharge pressure is typically higher due to the increased demand for heat extraction from the refrigerant.

The correct range indicates that for typical refrigerants used in residential air-to-air heat pumps, and considering the specific conditions given, a discharge pressure of 255 to 275 psig is expected. This range is consistent with standard operational pressures for systems working efficiently in cooler conditions, as the system must work harder to achieve the desired heating output.

Generally, as outdoor temperatures drop, the heat pump's compressor has to operate at higher pressures to maintain effective heating. Thus, the choice of 255 to 275 psig aligns with the necessary operational characteristics expected from such a system under the specified conditions.