Question 42General Subjects - Assistant Engineer

The correct answer is D) Faulty operation of a cylinder unloader. The faulty operation of a cylinder unloader is the probable cause for the improper functioning of a reciprocating air compressor's suction valve. The unloader is responsible for unloading the compressor's cylinders during the starting process, which allows the compressor to reach its operating speed without excessive load. If the unloader is not working correctly, it can prevent the suction valve from opening and closing properly, leading to the compressor's faulty operation. The other options are not directly related to the suction valve's improper functioning. Carbon build-up in the piston ring belt (A) and compressor operation in high humidity (C) may affect the compressor's overall performance, but they do not specifically cause issues with the suction valve. The lifting of the intercooler relief valve (B) is a separate problem that does not directly impact the suction valve.