It is a documented fact that low airflow exists in more than 50% of heat pump systems in the U.S.  (google “DOE/ENERGY STAR low airflow in heat pumps”).  It is widely known that low airflow will cause auxiliary electric heaters to short- cycle by their auto-reset primary high temperature safety limits and become inoperative (as they are designed to do) by their secondary back-up safety limits.  It is also widely known that low airflow will cause heat pump compressors to short- cycle by their auto-reset high head pressure limits.  Both the electric heater and the compressor are subject to premature failure depending on the degree of low airflow and the length of time in use.

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