It may be a mechanical failure of the pump, or it may be due to restricted suction pipes causing cavitation (noise). In case of abnormal sound, the water pump can be tested separately without connecting the pipeline system. If the noise is eliminated, it is due to the unsmooth system pipeline causing uneven exhaust, resulting in abnormal sound. If the water pump is tested separately and there is no dry running or noise, it needs to be sent back to TOPSFLO for quality analysis of the cause.