1. What is a Boiler Flow Rate Calculator?

Definition: This calculator determines the required flow rate for a boiler system based on heat output, specific heat constant, and temperature difference.

Purpose: It helps HVAC professionals and engineers properly size boiler systems and ensure adequate water circulation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Flow \) — Flow rate (gallons per minute)
• \( Q \) — Heat output (BTU per hour)
• \( c \) — Specific heat constant (500 for water)
• \( \Delta T \) — Temperature difference (°F)

Explanation: The heat output is divided by the product of specific heat constant and temperature difference to determine required flow rate.

3. Importance of Flow Rate Calculation

Details: Proper flow rate ensures efficient heat transfer, prevents boiler short cycling, and maintains system efficiency.

4. Using the Calculator

Tips: Enter the heat output in BTU/h, specific heat constant (default 500 for water), and temperature difference in °F. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the specific heat constant for other fluids?
A: For glycol mixtures, use 470-490; for oil, use about 400. Water's 500 is most common.

Q2: How do I determine temperature difference?
A: Subtract return water temperature from supply water temperature (typically 20°F for residential systems).

Q3: What if my system uses metric units?
A: Convert kW to BTU/h (1 kW = 3412 BTU/h) and °C to °F before using the calculator.

Q4: Does pipe size affect flow rate?
A: Yes, but this calculator gives the required flow - pipe sizing comes after to achieve that flow.

Q5: What's a typical flow rate for residential boilers?
A: Most residential systems need 5-15 gpm, but always calculate based on your specific system requirements.