1. What is a Pressure Tank Sizing Calculator?

Definition: This calculator determines the required size of a pressure tank based on water flow rate, desired drawdown time, and pump cycles per hour.

Purpose: It helps engineers, plumbers, and homeowners properly size pressure tanks for water systems to ensure efficient operation and pump longevity.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V_{tank} \) — Required tank volume (gallons)
• \( Q \) — Flow rate (gallons per minute)
• \( t \) — Desired drawdown time (minutes)
• \( C \) — Pump cycles per hour (dimensionless)

Explanation: The flow rate multiplied by drawdown time gives the required drawdown volume, which is then divided by the desired cycles per hour to determine tank size.

3. Importance of Proper Tank Sizing

Details: Correct tank sizing prevents short cycling of pumps, maintains consistent water pressure, and extends the life of your water system components.

4. Using the Calculator

Tips: Enter the flow rate in gpm, desired drawdown time in minutes, and cycles per hour (default 6). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical value for cycles per hour?
A: Most systems use 6-10 cycles per hour. Lower values (4-6) extend pump life but require larger tanks.

Q2: How do I determine my flow rate (Q)?
A: Measure at a faucet (gallons collected in 1 minute) or sum the flow rates of all fixtures that might run simultaneously.

Q3: What's a reasonable drawdown time?
A: Typically 1-2 minutes for residential systems, longer for systems with high intermittent demand.

Q4: Does this work for all pressure tank types?
A: This calculates drawdown volume. For bladder/diaphragm tanks, this is the tank size. For plain tanks, actual size will be larger.

Q5: Should I add a safety factor?
A: Yes, consider adding 10-20% to the calculated volume for system variations and future needs.