1. What is the Orifice Size Calculator?

The Orifice Size Calculator determines the appropriate diameter for an orifice in a water heater system to achieve the desired flow rate based on pressure differential and fluid properties.

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

Where:

• \( Q \) — Flow rate (GPM)
• \( C_d \) — Discharge coefficient (typically 0.6-0.65)
• \( A \) — Orifice area (ft²)
• \( g \) — Gravitational acceleration (32.2 ft/s²)
• \( h \) — Head loss (ft)

Explanation: The equation calculates the required orifice area based on the desired flow rate and available pressure differential.

3. Importance of Proper Orifice Sizing

Details: Correct orifice sizing ensures optimal water heater performance, prevents excessive pressure drops, and maintains system efficiency.

4. Using the Calculator

Tips: Enter required flow rate in GPM, pressure differential in psi, select appropriate discharge coefficient (default is 0.61 for sharp-edged orifices), and fluid type.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient (Cd)?
A: For sharp-edged orifices, Cd is typically 0.61. For rounded orifices, it may be higher (up to 0.8-0.9).

Q2: How does fluid type affect the calculation?
A: The calculator accounts for different fluid densities. Glycol mixtures have higher viscosity than water.

Q3: What pressure differential should I use?
A: Measure the actual pressure drop across the orifice location in your system.

Q4: Are there limitations to this calculation?
A: This assumes steady, incompressible flow and may need adjustment for very high or low flow rates.

Q5: How precise should the orifice diameter be?
A: For most applications, precision to 0.001 inches is sufficient.