Load Pulse™ – DuctPro User Guide

Introduction

Load Pulse™ – DuctPro is a professional-grade HVAC duct sizing and airflow calculation tool designed for contractors, technicians, and engineers. This application helps you determine appropriate duct dimensions, airflow rates, and pressure losses based on your input parameters.

Getting Started

When you first open the DuctPro application, you’ll see a clean interface with several input fields and options:

1. Duct Type Selection – Choose between Round or Rectangular ducts
2. Input Fields – Enter your known parameters (CFM, Velocity, Duct Size)
3. Material Selection – Choose the type of duct material
4. Calculate Button – Process your calculations
5. Help Button – Access this user guide and additional information

Understanding the Parameters

Before starting your calculations, it’s important to understand what each parameter represents:

CFM (Cubic Feet per Minute)

This measures the volume of air flowing through your duct system. It’s a crucial factor in determining proper duct sizing.

Velocity (Feet per Minute)

This is how fast the air moves through your ductwork. Standard residential velocities typically range from 800-1200 fpm, while commercial systems may be higher.

Duct Size

For round ducts, this is the diameter in inches. For rectangular ducts, this refers to width and height measurements in inches.

How to Use the Application

Step 1: Select Duct Type

The application allows you to work with both round and rectangular duct configurations:

• Round Ducts: Click the “Round” radio button
• Rectangular Ducts: Click the “Rectangular” radio button

When you select rectangular ducts, two input fields will appear for width and height measurements.

Step 2: Enter Your Known Parameters

You need to enter at least two of the three parameters (CFM, Velocity, Duct Size) to get a calculation result. The application will automatically calculate the third missing parameter.

Example 1 – Round Duct

• Enter CFM = 500
• Enter Velocity = 1000 fpm
• Leave Duct Size blank
• The app will calculate the required duct diameter

Example 2 – Rectangular Duct

• Enter CFM = 800
• Enter Velocity = 900 fpm
• Leave Width/Height blank
• The app will calculate the required rectangular dimensions using the standard 2:3 ratio

Step 3: Select Duct Material

Choose the appropriate duct material from the dropdown menu:

• Standard: Default setting for typical rigid ductwork
• Flexible Duct: Higher friction loss factor
• Fiberglass: Higher friction loss factor

The material selection affects the pressure loss calculations in your results.

Step 4: Calculate Your Results

After entering at least two parameters, tap the “CALCULATE” button. The application will process your inputs and display the complete results including:

• CFM (Cubic Feet per Minute)
• Velocity (Feet per Minute)
• Friction Loss (inches of water gauge per 100 feet of duct length)
• Duct Dimensions (diameter for round, width x height for rectangular)
• Material Used

Example Calculations

Example 1: Determining Required Duct Size

You have a system with:

• CFM = 600
• Velocity = 1200 fpm
• Duct Type = Round
• Material = Standard

Steps:

1. Select “Round” duct type
2. Enter 600 in the CFM field
3. Enter 1200 in the Velocity field
4. Leave Duct Size blank
5. Select “Standard” material
6. Tap CALCULATE

Result: The application will show the required duct diameter along with all other calculated parameters.

Example 2: Rectangular Duct Sizing

You need to size rectangular ductwork for:

• CFM = 1000
• Velocity = 850 fpm
• Duct Type = Rectangular
• Material = Flexible Duct

Steps:

1. Select “Rectangular” duct type
2. Enter 1000 in the CFM field
3. Enter 850 in the Velocity field
4. Leave Width/Height blank
5. Select “Flexible Duct” material
6. Tap CALCULATE

Result: The application will calculate and display the required width and height dimensions using the 2:3 ratio.

Important Features and Notes

Automatic Ratio Calculation for Rectangular Ducts

When working with rectangular ducts, the application uses a standard 2:3 width-to-height ratio. This means:

• Width is 2 units
• Height is 3 units
• This ratio provides optimal airflow characteristics for most HVAC applications

Friction Loss Calculations

The application calculates friction loss in inches of water gauge per 100 feet of duct length. This value helps determine pressure drops throughout your system and ensures proper system design.

Data Persistence

All calculations are automatically saved to your device. You can return to previous calculations or start new ones without losing your work.

Troubleshooting Common Issues

No Results Displayed

If you don’t see calculation results:

1. Ensure you’ve entered at least two parameters
2. Check that all values are numeric (no letters or symbols)
3. Verify that your duct type is properly selected
4. Confirm that the material selection is made

Unexpected Results

If the calculated results seem incorrect:

1. Double-check all input values for accuracy
2. Ensure you’re using consistent units (inches, fpm, etc.)
3. Review the calculation scenarios in the help section
4. Consider consulting with a licensed HVAC professional for final verification

Using the Help System

The application includes comprehensive built-in help that you can access at any time:

1. Tap the “Help” button (usually located at the bottom of the screen)
2. Read the detailed instructions on how to use the application
3. Review calculation scenarios and parameter explanations
4. Access the Terms of Service and Privacy Policy information

Best Practices for Accurate Results

1. Use Realistic Values: Enter actual system requirements rather than estimates
2. Verify Input Data: Double-check all measurements before entering them
3. Consider System Requirements: Take into account the specific needs of your HVAC system
4. Consult Professionals: While this tool provides professional-grade calculations, always verify results with a licensed HVAC technician for final design decisions

Important Disclaimers

• These calculations are estimates designed for initial planning purposes
• Professional HVAC sizing requires detailed analysis including ductwork, insulation, and local conditions
• Results should be verified by licensed HVAC technicians for final equipment selection
• The application uses industry-standard engineering principles but cannot replace professional engineering judgment

Conclusion

Load Pulse™ – DuctPro provides powerful yet accessible tools for HVAC professionals and homeowners alike. By following these guidelines and understanding the application’s capabilities, you can make informed decisions about your duct sizing and airflow requirements.

Remember to always consult with qualified HVAC professionals for final system design and installation decisions. The DuctPro application is a valuable planning tool that helps ensure proper system sizing and performance.

For additional information or support, please contact our team at info@loadpulse.app.