Quality Control & Process Improvement Flashcards

An inspection finds that pipe insulation joints on an outdoor solar loop are not sealed with weatherproof tape. What quality risk does this create?

Answer: Water ingress that degrades insulation R-value and accelerates corrosion

Unsealed insulation joints allow moisture infiltration, which drastically reduces thermal resistance and can lead to corrosion of the underlying pipe.

Which element of ISO 9001 quality management principles is most directly applied when a solar installation company creates and follows written installation procedures?

Answer: Process approach

Documented, standardized procedures represent the 'process approach' principle, ensuring activities are managed as defined processes to achieve consistent results.

During final inspection, the inspector finds that the pressure relief valve discharge pipe terminates inside the mechanical room wall cavity. What is the quality concern?

Answer: The discharge cannot be observed, and scalding fluid could discharge unsafely into the wall cavity

PRV discharge pipes must terminate in a visible, safe location so that activation can be detected and scalding fluids are safely directed away from occupants and structure.

A solar installation crew consistently over-tightens compression fittings, leading to cracked ferrules. The best process improvement is to:

Answer: Add torque specifications to the installation procedure and provide torque wrenches

Specifying and measuring torque converts a skill-dependent task into a repeatable process, preventing over-tightening without relying solely on technician judgment.

What does 'first-pass yield' measure in a solar installation quality program?

Answer: The percentage of installations completed without any rework or defect correction

First-pass yield tracks how often work is done correctly the first time, serving as a key metric for overall process quality and efficiency.

When reviewing an installed solar thermal system, an inspector verifies that the expansion tank is sized and located correctly. Why does location matter for quality?

Answer: The tank must be on the suction side of the pump to prevent pump cavitation and ensure proper pressurization

Installing the expansion tank on the pump suction side ensures the system reference pressure point is at the pump inlet, preventing both cavitation and pressure fluctuation problems.

A company reviews warranty claim data and finds that 70% of claims involve controller sensor failures. Using a Plan-Do-Check-Act (PDCA) cycle, what is the 'Plan' step?

Answer: Analyze failure modes, identify root causes, and develop a corrective action strategy

The 'Plan' phase of PDCA requires understanding the problem and its root causes before defining and implementing a solution.