What problem could produce a high absolute pressure within a flash type evaporator?

A cracked distillate pump vent line can lead to a high absolute pressure within a flash type evaporator because it disrupts the necessary venting of the system. In a well-functioning evaporator, any vapor created needs to be properly vented to maintain the right pressure balance. If the vent line is compromised, it can prevent vapor from escaping, leading to an accumulation of pressure within the evaporator. As pressure increases, it can interfere with the evaporator's ability to function correctly, causing operational problems and impacting the efficiency of the entire system.

In contrast, a clogged filter primarily restricts flow rather than directly affecting pressure in the evaporator. Low refrigerant levels typically create low pressure conditions, which is opposite to the scenario described. A faulty expansion valve may lead to improper refrigerant flow but would not directly cause a dramatic increase in absolute pressure as would an obstruction in the venting system.