Charring or glazing of the inner circumference of the packing rings in a centrifugal pump is caused by __________.

Correct Answer: Option B — insufficient lubrication of the packing

Packing rings rely on the pumped fluid to provide essential lubrication and heat dissipation. If the gland is too tight or the fluid flow is restricted, friction between the packing and the shaft sleeve generates excessive heat, causing the packing material to char or glaze, which further accelerates wear and leakage.