CSLB C-36 Plumbing ContractorFixture and Appliance InstallationHard

A plumber is called to a commercial building to address a consistently running toilet. Upon inspection, the plumber determines that the fill valve is faulty. The building's plumbing system operates at a higher-than-average water pressure. When selecting a replacement fill valve, what characteristic is most important to consider for durability and reliable operation in this scenario?

  1. AA diaphragm-type fill valve designed for high pressure.
  2. BA float-cup type fill valve for quiet operation.
  3. CA low-flow fill valve to conserve water.
  4. DA universal fill valve for ease of installation.
Show answer & explanation

Correct answer: A. A diaphragm-type fill valve designed for high pressure.

In high-pressure environments, a diaphragm-type fill valve is generally preferred over plunger or float-cup types because its design is more robust and less prone to wear and tear from constant high pressure, leading to greater durability and reliable shut-off.

Why the other options are wrong

  • B. Float-cup types can be quiet but may not be as durable under sustained high pressure as diaphragm types.
  • C. Low-flow is a water conservation feature, not directly related to durability under high pressure.
  • D. Universal valves prioritize compatibility and ease of installation, but not necessarily durability in specific high-pressure conditions.

Diaphragm Fill Valve

A type of toilet fill valve that uses a flexible diaphragm to control water flow, offering excellent sealing and durability, especially in high-pressure systems.

  • More durable and less prone to leaks than plunger-type valves.
  • Often quieter in operation.
  • Suitable for high water pressure environments.

Memory trick: For high pressure, 'Diaphragm' valves 'Deliver Durability'.

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