CSLB C-46 Solar ContractorSolar Thermal System InstallationEasy
A solar thermal installer is performing the initial fill of a closed-loop propylene glycol system. To ensure adequate freeze protection for the expected winter temperatures of -10°F, what tool is essential for verifying the concentration of the glycol solution after mixing and filling?
- ARefractometer
- BOhmmeter
- CPressure gauge
- DpH meter
Show answer & explanationAnswer & explanation
Correct answer: A. Refractometer
A refractometer is specifically designed to measure the concentration of glycol in a solution, which directly correlates to its freeze protection capability. A pH meter checks acidity, an ohmmeter checks electrical resistance, and a pressure gauge measures system pressure, none of which directly verify glycol concentration for freeze protection.
Why the other options are wrong
- B. An ohmmeter measures electrical resistance and is used for testing electrical components like sensors, not for glycol concentration.
- C. A pressure gauge measures system pressure, which is vital for system integrity but does not indicate glycol concentration.
- D. A pH meter measures the acidity/alkalinity of the fluid, important for corrosion protection, but not directly for freeze protection concentration.
Glycol Concentration Testing
The process of using a refractometer to measure the percentage of glycol in a heat transfer fluid to ensure it provides adequate freeze protection for solar thermal systems.
- Uses a refractometer
- Measures refractive index
- Correlates to freeze point
- Crucial for winter operation
Memory trick: For glycol's freeze, a refractometer's ease.