Some manufacturers leave fittings loosely tightened to allow for what during shipping and storage?

The reasoning behind leaving fittings loosely tightened by some manufacturers relates to the need for flexibility due to temperature changes. During shipping and storage, a variety of temperature fluctuations can occur. These fluctuations can cause materials to expand or contract, and if the fittings were tightly secured, this could lead to stress, misalignment, or even damage to the components when temperatures rise or fall.

By not tightening the fittings fully, the manufacturer allows for a certain degree of movement and adjustment, which helps to mitigate potential issues caused by thermal expansion or contraction. This practice helps ensure that the components remain in good condition and function properly when finally installed.