CSLB C-36 Plumbing ContractorPlanning and EstimatingMedium
A plumbing contractor is reviewing a blueprint for a new high-rise residential building. The design specifies a centralized domestic hot water (DHW) system. To ensure that hot water is delivered quickly to fixtures on upper floors without excessive waiting, which system component is essential to minimize water waste and improve user convenience?
- AA pressure-reducing valve (PRV)
- BA thermostatic mixing valve (TMV)
- CA hot water recirculation pump
- DAn expansion tank
Show answer & explanationAnswer & explanation
Correct answer: C. A hot water recirculation pump
A hot water recirculation pump continuously circulates hot water through a dedicated loop, ensuring that hot water is readily available at fixtures, reducing wait times and water waste.
Why the other options are wrong
- A. A PRV reduces water pressure, not hot water delivery time.
- B. A TMV controls water temperature at the point of use, not the speed of delivery.
- D. An expansion tank absorbs thermal expansion, protecting the water heater and system, but does not speed up hot water delivery.
Hot Water Recirculation System
A plumbing system designed to provide instant or near-instant hot water at fixtures by continuously circulating hot water through a dedicated loop back to the water heater.
- Reduces water waste by eliminating the need to run cold water down the drain while waiting for hot.
- Improves user convenience by providing hot water quickly.
- Consists of a pump, a return line, and often a timer or demand sensor.
- Can increase energy consumption if not properly designed and insulated.
Memory trick: Pump the loop, hot water soon, no cold wait.