Why should a heat pump compressor not be turned back on immediately after being shut off?

Turning a heat pump compressor back on immediately after it has been shut off can lead to potential damage or reduced efficiency due to high refrigerant pressure on the discharge side. When the compressor stops, the refrigerant pressure may not equalize immediately, and if the compressor is restarted while the discharge pressure is still elevated, it can lead to excessive strain on the compressor components.

Moreover, the compressor's internal parts, such as the bearings, can experience increased wear or even failure because they need to operate within certain pressure limits for proper lubrication and cooling. Allowing time for the system's pressures to stabilize helps prevent operational issues and extends the lifespan of the compressor.

In contrast, the other options highlight situations that do not specifically address the immediate mechanical or operational impacts of restarting under high-pressure conditions. Therefore, ensuring that the compressor is not restarted until the refrigerant pressures have balanced is critical for system longevity and functionality.