BACK

#hsi

Tech Tips:

Silicon Carbide vs. Silicon Nitride Hot Surface Ignitors (HSIs)

The ignitor of a furnace (or a gas pool heater or other gas-fired appliance) is the heat source, and it can come in one of four varieties: standing pilot, direct spark (DS), intermittent spark (ISI), and hot surface (HSI). We have a tech tip explaining each of these ignitor types in detail, but we’re going […]

The New HSI Module from White Rodgers

Jim Fultz returns to the podcast to talk about the new HSI module from White-Rodgers, the 50E47U-843. You can learn more about this new universal HSI module at https://hvacrschool.com/hsimodule. Hot surface ignition modules control the burner for gas appliances that use hot surface ignition, not just furnaces. Since the HSI module doesn't need to work […]

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this comprehensive training session from the symposium, Tony Gonzalez, Training Director at Fieldpiece, delivers an engaging and practical guide to combustion analysis for HVAC technicians. With 25 years of experience at Fieldpiece—from warehouse worker to training director—Tony brings both technical expertise and real-world application to this 50-minute interactive session focused on the company’s CAT 85 combustion analyzer.

Tony emphasizes that combustion analysis serves four critical purposes: safety, efficiency, equipment specification verification, and liability protection. He makes a compelling business case for investing in combustion analyzers, noting that preventing just two callbacks or one liability lawsuit can pay for the equipment ten times over. The training walks attendees through the complete process, from properly warming up the analyzer in fresh air (allowing sensors to calibrate to ambient oxygen and zero carbon monoxide) to generating professional PDF reports that can be shared with customers or integrated into work order management systems like ServiceTitan.

The session provides detailed guidance on interpreting key measurements, including stack temperature, oxygen percentage, carbon monoxide levels, and draft pressure. Using design parameters from the National Comfort Institute, Tony demonstrates how to diagnose issues by comparing actual readings against acceptable ranges for different furnace types (atmospheric, 80% induced fan, and 90+ percent condensing). He walks through practical troubleshooting scenarios, showing how measurements like high oxygen combined with low stack temperature can point to specific problems like low gas pressure that technicians can then verify and correct.

Throughout the presentation, Tony emphasizes proper technique and best practices, from creating test ports at least 12 inches above the inducer fan to the importance of plugging test ports after completion. He also highlights innovative features of Fieldpiece’s analyzers, including the hydro cycle pump that eliminates traditional water traps, sensor vault technology that extends sensor life to four years, and built-in wireless connectivity allowing technicians to view measurements on their mobile devices through the Job Link app.

Topics Covered:

Why perform combustion analysis: Safety verification, efficiency optimization, OEM specification compliance, and liability protection
Business benefits: Reducing callbacks, improving OEM relationships, enhancing professional image, and protecting against lawsuits
Proper startup procedure: Warming up analyzers in fresh air for accurate oxygen and CO sensor calibration
Ambient CO testing: Using combustion analyzers vs. dedicated walk-around detectors for carbon monoxide detection in living spaces
Test port installation: Proper placement at least 12 inches above inducer fans and away from 90-degree elbows
Key measurements explained: Stack temperature, oxygen percentage, CO PPM, CO air-free, draft pressure, and efficiency calculations
Equipment type selection: Choosing correct settings for atmospheric, 80% induced fan, or 90+ percent condensing furnaces
Diagnostic interpretation: Using National Comfort Institute parameters to identify issues like excess combustion air or low gas pressure
Advanced features: Built-in dual port manometer for gas and static pressure, wireless Job Link app connectivity, and hydro cycle pump technology
Report generation: Creating professional PDF reports with company branding for customer documentation and CYA protection
Maintenance tips: Checking particle filters, understanding sensor vault technology, and the importance of annual calibration
Sensor longevity: Four-year sensor life warranty and field-replaceable sensors without sending equipment for service

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Search Episodes

Combustion Analysis w/ Tony G.

12/25/2025

Bryan Orr

Give Until it Hertz – The Battle Over Frequency – Short #271

12/23/2025

Bryan Orr