Piping System Brain Teaser #4: System Troubleshooting Part 2
Last month we looked at the operating conditions of a couple of systems to determine the root cause of a problem that was occurring in the system. This month we'll look at two more.
To recap, a key aspect of troubleshooting a problem in a piping system is knowing what the "normal" operating conditions are for the flow rates, pressures, valve positions, and other measured values in the system. If you don't know what is "normal", it will be hard to identify an "abnormal" operating condition.
The end result of troubleshooting is to determine the root cause of the problem and fix it. Many times troubleshooting becomes an exercise in how many components can be torn apart or replaced in hopes of finding that root cause. But if you understand the operation of each component in the system and how the total system operates, troubleshooting becomes a methodical and logical analysis of the values of process measurements throughout the system.
Given the normal operating conditions shown in Figure 1, determine the root cause of the problems indicated by the process measurements in Figures 4 and 5. Potential Root Causes are listed below the Figure 5.
Figure 1. Normal operating conditions
Figure 4. Problem 3: There are pressure oscillations on the pump supply and discharge pressure gauges.
Figure 5. Problem 4: Operators are complaining about poor temperature and flow control of the heat exchanger.
|Problem 3: _______________||Root Cause A: Excessive Control Valve seat or disc wear|
|Problem 4: _______________||Root Cause B: Supply Tank Level Transmitter incorrect|
|Root Cause C: Plugged Heat Exchanger|
|Root Cause D: Supply Pump damaged or worn|
SOLUTIONS: 3-B, 4-A