CSLB C-46 Solar ContractorElectrical and Plumbing CodesEasy

A solar contractor is installing a new solar thermal system for domestic hot water. Which of the following is the maximum pressure relief valve (PRV) setting allowed for a potable water heater, as per the Uniform Plumbing Code (UPC)?

  1. A200 PSI
  2. B100 PSI
  3. C125 PSI
  4. D150 PSI
Show answer & explanation

Correct answer: D. 150 PSI

The Uniform Plumbing Code (UPC) specifies that the maximum pressure relief valve (PRV) setting for a potable water heater should not exceed 150 PSI to ensure safety and prevent over-pressurization.

Why the other options are wrong

  • A. This is above the maximum allowed pressure for a potable water heater PRV and would be unsafe.
  • B. This is below the maximum allowed pressure for a potable water heater PRV.
  • C. This is below the maximum allowed pressure for a potable water heater PRV.

Potable Water Heater PRV Setting (UPC)

The maximum pressure at which a pressure relief valve (PRV) on a potable water heater is permitted to open, as regulated by the Uniform Plumbing Code (UPC), to prevent dangerous over-pressurization.

  • Ensures safety of the water heater and plumbing system.
  • Protects against excessive internal pressure.
  • Mandatory safety device for all potable water heaters.

Memory trick: Safe water pressure keeps the hot water flowing, not blowing.

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