Installation Procedures Flashcards
7 cards from real CCT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Installation Procedures flashcards as text
Why must impulse lines for differential pressure flow measurement be sloped continuously from the process taps to the transmitter with no low points?
Answer: To ensure gas bubbles or condensate pockets cannot accumulate and create false differential pressure
Trapped gas or liquid pockets in impulse lines create density-based head errors that offset the differential pressure reading.
When installing a control valve, what is the standard recommended upstream and downstream straight pipe run to prevent cavitation-induced damage?
Answer: 10D upstream and 5D downstream
The typical industry guideline is 10 pipe diameters (10D) upstream and 5 diameters (5D) downstream to allow the flow profile to stabilize before and recover after the valve.
During the mechanical installation of an orifice plate, what common error will cause the measured differential pressure to be erroneously high?
Answer: Reversing the orifice plate so the beveled edge faces upstream
Reversing the orifice plate places the sharp edge downstream, changing the vena contracta location and producing a higher-than-expected differential pressure.
What is the purpose of a manifold valve assembly (3-valve or 5-valve) used during transmitter installation?
Answer: To allow the transmitter to be zeroed, calibrated, or removed without shutting down the process
The manifold isolates, equalizes, or vents the transmitter so it can be calibrated or maintained while the process remains pressurized.
A gas chromatograph analyzer is being installed for a process sample system. What is the critical role of sample conditioning upstream of the analyzer?
Answer: To bring the sample to the correct temperature, pressure, flow rate, and remove particulates and liquid dropouts
Sample conditioning ensures the analyzer receives a clean, representative sample within its specified operating envelope, preventing damage and measurement errors.
When field-wiring a 4-20 mA two-wire transmitter, what is the correct way to verify polarity before energizing the loop?
Answer: Use a multimeter in DC voltage mode to confirm the supply positive connects to the transmitter positive terminal
Confirming DC voltage polarity before energizing prevents reverse-polarity damage to the transmitter's internal electronics.
Which installation standard requires calibration records to be traceable back to a national or international standard?
Answer: ISO/IEC 17025
ISO/IEC 17025 is the international standard governing calibration laboratory competence, requiring traceability of measurement results to national or international measurement standards.