CSLB C-36 Plumbing ContractorFixture and Appliance InstallationMedium
A commercial kitchen is upgrading its dishwashing system. The new high-temperature dishwasher requires a sustained hot water supply at 180°F (82°C) for sanitization. The existing hot water heater can only reliably provide water at 140°F (60°C). To meet the sanitization temperature requirement without replacing the main water heater, which of the following is the most appropriate plumbing solution?
- AInsulating the existing hot water supply lines more thoroughly.
- BAdding a dedicated booster heater for the dishwasher.
- CInstalling a thermostatic mixing valve (TMV) at the dishwasher.
- DIncreasing the size of the hot water supply line to the dishwasher.
Show answer & explanationAnswer & explanation
Correct answer: B. Adding a dedicated booster heater for the dishwasher.
A booster heater is specifically designed to raise the temperature of already hot water (e.g., from 140°F to 180°F) for specific applications like high-temperature dishwashers. This allows the main water heater to operate at a safer, lower temperature while meeting the sanitization needs.
Why the other options are wrong
- A. Insulation reduces heat loss but cannot raise the water temperature above what the main water heater provides.
- C. A TMV mixes hot and cold water to lower the temperature, which is the opposite of what's needed here.
- D. Increasing the supply line size might improve flow, but it will not increase the water temperature from the source.
Dishwasher Booster Heater
A booster heater is a compact water heater installed in-line, typically near a commercial dishwasher, to raise the incoming hot water temperature (e.g., from 140°F) to the higher temperature required for sanitization (e.g., 180°F).
- Raises water temperature for sanitization.
- Common in commercial kitchens.
- Allows main heater to operate at lower, safer temps.
Memory trick: Need more heat? A booster's neat!