CSLB C-46 Solar ContractorElectrical and Plumbing CodesMedium
A solar contractor is installing a new solar thermal system for domestic hot water. The system includes a storage tank that will be supplied by the municipal water main. According to the California Plumbing Code (CPC), what is the maximum pressure relief valve setting for a potable water heater, unless otherwise specified by the manufacturer?
- A125 psi
- B100 psi
- C150 psi
- D75 psi
Show answer & explanationAnswer & explanation
Correct answer: C. 150 psi
The California Plumbing Code (CPC) Section 504.4, referencing UPC 504.4, specifies that the pressure relief valve for a potable water heater shall not be set to open at more than 150 psi. This ensures the safe operation of the water heater under normal and abnormal pressure conditions.
Why the other options are wrong
- A. 125 psi is below the maximum allowed by CPC for potable water heaters.
- B. 100 psi is below the maximum allowed by CPC for potable water heaters.
- D. 75 psi is too low for typical potable water heater pressure relief settings.
Potable Water Heater PRV Max Setting
The maximum pressure relief valve setting for a potable water heater, as per CPC, is 150 psi, unless manufacturer specifications dictate a lower value.
- Ensures safety and prevents tank rupture.
- Applies to domestic hot water systems.
- Referenced in CPC Section 504.4 (UPC 504.4).
Memory trick: Pressure Relief Valve: 150 is the Max Safe Threshold.