Final answer:
To dislodge debris in the pressure-balancing spindle of a T/P valve, blowing compressed air is typically the most effective means.
Step-by-step explanation:
To dislodge debris from the pressure-balancing spindle of a T/P (Temperature and Pressure) valve, option b. blowing compressed air is generally the most effective method. Compressed air can forcefully eject any particles or sediments that might be obstructing the spindle. In contrast, options such as a. tapping with a hammer might damage the valve components, while c. flushing with vinegar might help dissolve mineral deposits but not necessarily dislodge larger debris. Ignoring the problem, as option d. suggests, will not resolve the issue and might lead to further valve malfunctions. It's important to handle such maintenance with care to ensure the proper functioning of the T/P valve.