What happens if the key between impeller and shaft is not present?

If the key between the impeller and shaft is not present, the impeller may not be securely attached to the shaft, leading to slippage during operation. This can cause a loss of rotational force, resulting in reduced pump efficiency and potentially damaging the equipment. Additionally, vibrations and misalignment may occur, increasing the risk of mechanical failure and costly repairs. Overall, the absence of the key compromises the integrity and performance of the system.