What happens to the heater elements if airflow is too low?

When airflow through the heating elements of a heat pump is too low, the elements can indeed become excessively hot. This is primarily because proper airflow is essential for effective heat exchange and distribution of heat within the system.

When there is insufficient airflow, the heater elements will not have enough surrounding air to dissipate the heat they are generating. Consequently, as they continue to operate, they become hotter since the heat they produce isn't being drawn away efficiently by the moving air. This can lead to overheating, which can damage the elements and create a risk of failure or fire hazard due to the elevated temperatures.

In situations where airflow is adequate, the heat generated by the elements is effectively transferred to the air being circulated, leading to normal operating conditions. If the airflow is too low, the important balance and safety considerations within the HVAC system are disrupted, resulting in the heater elements experiencing excessive heat.