Condensate Pumping

Calculate Net Positive Suction Head (NPSH) for condensate pumping systems to prevent cavitation in centrifugal pumps handling hot condensate near boiling temperatures.

Calculator

Inputs

Water Density (lb/ft³)

Absolute Pressure in Receiver (psi)

Absolute Evaporation Pressure (psi)

Static Suction Head (ft)

Friction Loss in Suction Piping (ft)

Results

Net Positive Suction Head (NPSH)-- ft

Temperature (°F)	Temperature (°C)	Vapor Pressure (psi)	Density (lb/ft³)	Typical Cavitation Risk
100	37.8	0.949	62	Low
120	48.9	1.695	61.7	Low
140	60	2.892	61.4	Moderate
160	71.1	4.741	61	Moderate
180	82.2	7.51	60.6	High
200	93.3	11.526	60.1	High
212	100	14.696	59.8	Critical

NPSH Guidelines

Recommended NPSH Values

Minimum Required: Consult pump manufacturer specifications
Typical Safety Margin: Add 2-3 ft to manufacturer's minimum
Positive Value: Indicates protection against cavitation
Negative Value: High risk of cavitation - system modifications needed

Methods to Increase NPSH

Increase Receiver Pressure - Pressurize receiver above atmospheric
Reduce Vapor Pressure - Cool condensate with heat exchanger
Increase Static Head - Elevate receiver or lower pump
Reduce Friction Loss - Increase piping diameter, reduce fittings
Use Pressure-Powered Pump - Alternative to centrifugal pump

Temperature Effects

Hot condensate near 211°F (100°C) has vapor pressure approaching atmospheric pressure, making cavitation likely. Temperature reduction is often the most practical solution.

Condensate Pumping | MEPKit Engineering Tools | MEPKit