CSLB C-46 Solar ContractorSolar Thermal System InstallationMedium
A solar thermal system installer is preparing to pressure test a newly installed closed-loop glycol system. The system has a maximum operating pressure of 50 psi. According to industry best practices and common code requirements, what is the recommended minimum test pressure for this system?
- A50 psi
- B150 psi
- C100 psi
- D75 psi
Show answer & explanationAnswer & explanation
Correct answer: D. 75 psi
Industry best practices and many codes, such as the Uniform Solar Energy Code (USEC), require pressure testing at 1.5 times the maximum operating pressure. For a 50 psi operating pressure, this would be 1.5 * 50 psi = 75 psi.
Why the other options are wrong
- A. Testing at operating pressure may not reveal marginal leaks that could develop under slightly higher pressure.
- B. 150 psi is excessive for a system with a 50 psi operating pressure and could potentially damage components if not designed for it.
- C. While 100 psi would test the system, 1.5 times the operating pressure is the specific minimum standard.
Solar Thermal Pressure Test
A pressure test verifies the integrity of solar thermal piping and components by subjecting the system to a pressure higher than its normal operating pressure to detect leaks.
- Typically performed with water or air/nitrogen.
- Commonly tested at 1.5 times the maximum operating pressure.
- Pressure should be held for a specified duration (e.g., 30 minutes to 2 hours) with no significant drop.
Memory trick: Operating pressure up by half, for a leak-free laugh.