Question 29General Subjects - Assistant Engineer

The correct answer is C) check the operation of the unloaders. If the drive belts on an air compressor are squealing during startup, it is likely due to the unloaders not functioning properly. The unloaders are responsible for relieving pressure in the system when the compressor is not running, which allows the compressor to start up without excessive load on the drive belts. If the unloaders are not operating correctly, the compressor will have to work against the residual pressure, causing the belts to squeal. Checking the unloaders and ensuring they are working as intended is the appropriate troubleshooting step in this scenario. The other answer choices, while potentially relevant in other situations, are not the primary cause of the squealing belts during startup in this case.