#zonal pressure diagnostics

Tech Tips:

The HVAC Technician’s Guide to Ensuring Comfort: Lessons from a Real-World Experience

This tech tip was written by Luke Peterson, the president of The Maintenance Department in Louisville, KY. Luke was a speaker at the 5th Annual HVAC Training Symposium in 2024 and has been on HVAC business panels at the symposium in 2023 and 2024. Thanks, Luke! As an HVAC technician, your primary goal is not […]

Solving Comfort and IAQ Issues in a Vintage Home: A Case Study

This tech tip is a recap of the Santa Fe Dehumidifiers and Comfort Dynamics, Inc. case study about a 1941 vintage home in Miami, FL. You can listen to the podcast about that case study by clicking the play button below, and you can read the case study at https://hvacrschool.com/case-study. Special thanks to Nikki Krueger […]

Zonal Pressure Diagnostics—The Backtalk Series (Part 3)

This article was submitted by Genry Garcia of Comfort Dynamics, Inc. It is the final part of his series on zonal pressure diagnostics. Thanks, Genry! Updated 3/4/2022 Picking up where we left off in part 2 of the series, we discussed how a pressure reading from an attached zone indicates only the ratio of the […]

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Chris Hughes and Steve Rogers from The Energy Conservatory discuss TEC’s TrueFlow technology and its crucial role in predicting airflow issues in the sales process, particularly for heat pump retrofits. They explain how the TrueFlow app helps contractors accurately measure both static pressure and airflow in existing systems, enabling them to predict whether proposed equipment changes will work effectively. This is especially vital when considering the growing trend of replacing gas furnaces with heat pumps, as the airflow requirements can differ significantly.

The conversation delves into a detailed example of replacing an 80% efficient 48,000 BTU furnace with a heat pump. They demonstrate how the airflow requirement would nearly double from 652 CFM to 1,200 CFM, potentially causing the static pressure to quadruple due to Fan Law 2 principles. This dramatic increase could lead to significant performance issues if not properly addressed during the system design phase. The experts emphasize that using TrueFlow during the sales process allows contractors to identify potential problems and necessary modifications before installation rather than discovering issues during callbacks.

The discussion also covers the ideal workflow for system assessment and sales, starting with customer comfort evaluation and proper load calculations. It’s important to reduce loads through envelope improvements when possible, particularly in cold climates where heat pump retrofits are becoming more common. Proper system sizing often means going smaller rather than larger, contrary to common industry practices, and the worst HVAC systems are often found in expensive custom homes rather than tract housing.

Key Topics Covered:

TrueFlow technology and its role in system forecasting
Fan Law 2 and its impact on static pressure when changing airflow
Heat pump retrofit challenges and considerations
The importance of accurate load calculations
Dual fuel systems as a solution for cold climates
The relationship between airflow and static pressure
Sales process integration of technical measurements
Common issues with oversized equipment
The importance of envelope assessment
Methods for reducing system loads
Proper duct sizing and modification strategies
The role of proper filter sizing and selection
The benefits of flat-rate pricing for duct modifications
Training resources and support available for TrueFlow users

Check out TEC’s YouTube channel at https://www.youtube.com/@energyconservatory, and you can visit TEC’s website at https://energyconservatory.com/.

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