Oilers/Plant Tenders (HHC) Civil Service Practice Exam

What is the most common fault that causes a sudden increase in oil pressure in a lubricating line to a bearing?

1. Clogged strainers

2. Bearing wear

3. Excessive oil viscosity

4. Unbalanced pressure relief valve

The correct answer is: Clogged strainers

A sudden increase in oil pressure in a lubricating line to a bearing is most commonly caused by clogged strainers. Strainers play a crucial role in filtering out contaminants from the oil before it reaches the bearings. When strainers become clogged, the flow of oil is restricted, causing a buildup of pressure upstream of the clog. This increase in pressure can potentially lead to damage within the lubrication system or the bearing itself if it exceeds the operational limits. In this context, bearing wear typically leads to lower oil pressure due to increased clearance and reduced resistance to flow, which is contrary to a sudden increase in pressure. Excessive oil viscosity might impact flow rates and the ability of oil to reach the bearings efficiently but does not typically cause an immediate spike in pressure; instead, it may lead to pressure drops in some situations. Finally, an unbalanced pressure relief valve can cause pressure issues, but this is generally not the most common cause compared to clogged strainers. Thus, the obstruction of flow due to clogging is the primary reason for the pressure increase in this scenario.