Chiller GPM Calculator

Pressure Drop Method

Enter design values and measured pressure readings to estimate chiller water flow

❄ Evaporator Flow

Design GPM

Design Pressure Drop (ft H₂O)

Click unit button to toggle ft H₂O / PSI

Entering Pressure (PSI)

Leaving Pressure (PSI)

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ChillerTrend.com

Calculated GPM: —

🔥 Condenser Flow

Design GPM

Design Pressure Drop (ft H₂O)

Click unit button to toggle ft H₂O / PSI

Entering Pressure (PSI)

Leaving Pressure (PSI)

Powered by
ChillerTrend.com

Calculated GPM: —

Formula used:

GPM₂ = GPM₁ × √(PD₂ / PD₁)

Explanation: This formula lets you turn a pressure drop into an estimated water flow rate. If you know what the chiller was designed for, you can use the pressure you're seeing now to figure out about where the flow is. The formula is easy but long, that's why we made this tool.

Want to compare this result to last month, document changes, or hand this to a customer? That requires a structured log.

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