The answer to 'heat pump blowing cold air' is that there are several common causes, including a refrigerant leak, a problem with the reversing valve, or a malfunctioning compressor. Symptoms may include the heat pump blowing cold air even when set to heat, the outdoor unit not running, or the system short-cycling. Solutions can range from simple DIY fixes like checking the thermostat settings to more complex repairs that require a professional HVAC technician.
If the heat pump is blowing cold air when it should be heating, the first step is to check the thermostat settings to ensure it is set to 'heat' mode. You can also try resetting the system by turning off power to the unit at the circuit breaker, waiting a few minutes, and then turning it back on. However, if the problem persists, it's likely due to a more serious issue that will require professional diagnosis and repair.