Journeyman Plumber ExamWater Supply SystemsMedium

A plumber is installing a water distribution system in a commercial kitchen. The hot water supply to a dishwashing machine requires a minimum temperature of 180°F (82°C). The building's main water heater only supplies water at 140°F (60°C). What type of water heater would typically be installed near the dishwashing machine to meet the required temperature?

  1. AA tempering valve.
  2. BA tankless coil water heater.
  3. CA point-of-use booster heater.
  4. DA solar water heater.
Show answer & explanation

Correct answer: C. A point-of-use booster heater.

A point-of-use booster heater is specifically designed to raise the temperature of already heated water from a central source to a higher temperature required by specific fixtures or appliances, such as commercial dishwashers, which often need water at 180°F for sanitization.

Why the other options are wrong

  • A. A tempering valve (or mixing valve) blends hot and cold water to lower the temperature, not raise it.
  • B. A tankless coil water heater is a type of water heater integrated with a boiler, providing domestic hot water, but it's not specifically for boosting an existing hot water supply to a higher temperature for a single appliance.
  • D. A solar water heater uses solar energy to heat water, typically supplementing a main water heater, but it doesn't guarantee a specific high temperature boost for a single appliance.

Booster Water Heater

A water heater designed to elevate the temperature of pre-heated water from a central source to a higher, specific temperature required by an appliance or fixture.

  • Common in commercial kitchens for dishwashers.
  • Raises water temperature for sanitization.
  • Typically electric or gas powered.

Memory trick: Dishwasher needs a boost, so a booster heater is the choice, not a roost.

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