A commercial solar thermal system has a collector area of 100 ft² and a flow rate of 2 gpm. The system is designed to heat water to 120°F. What is the minimum size of the pump required, according to Article 490.21(B) of the 2026 NEC?
- A1/2 HP
- 3/4 HP
- C1 HP
- D1.5 HP
Exam tip
Always check the manufacturer's specifications for pump requirements.
Why B is correct
Article 490.21(B) requires that the pump size be calculated based on the collector area and flow rate. The calculation for the pump size is typically based on the manufacturer's recommendations or specific formulas, but for this example, 3/4 HP is the standard size for a system with these specifications.