Two technicians are discussing refrigerant lines. technician a says that line connections must be tight but not so tight that air can't get through. technician b says that all connection o-rings have to be replaced when retrofitting a system to r-134a. who is correct?

The correct answer is: technician B, all connection O-rings have to ve replaced when retrofitting a system to R-134a.

Explanation:

When we have a refrigerant line, the refrigerant is used through a refrigeration cycle. Refrigerant should pass in a physical process of transformation, it should be pure, avoid another kind of phenomena.

When we are retrofitting a system to R-134a, it is thus necessary to change all connection O-rings. In that way, we can prevent the refrigerant of crossed contamination with other refrigerants or substances.

Let's analyze the opposite situation, if we do not change the O-rings and we change the refrigerant, probably there will be a few previous substances, which can react, or create other phenomena when they undergo the refrigeration cycle with the R-134 a. We have to avoid this situation. 

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the answer is true. hope it .