Why Combustion Analysis Matters

In the HVAC industry, the difference between a good technician and a great one often comes down to the tools they use and how they use them. When it comes to working with gas, oil, or propane appliances, combustion analysis isn’t just a recommended practice—it’s essential for safety, efficiency, and longevity.

The Hidden Dangers You Can’t See, Smell, or Hear

By performing a combustion analysis:

“We will find things that we simply cannot find with our eyes, our ears, or our nose.” – Jim

When you’re working on any fuel-burning appliance—whether it’s a 90+ furnace, an 80+ furnace, a boiler, or a hot water tank—combustion analysis provides critical data that would otherwise remain invisible.

Recently, one of TruTech Tools’ employees discovered their CO alarms going off with readings of 9-10 PPM in their home. The furnace had been tested the previous fall and was working properly. What happened? A leaf had worked its way into the venturi, affecting combustion, combined with a chimney that wasn’t quite tall enough, allowing flue gases to reenter the home through the attic. Without proper testing equipment, this potentially dangerous situation would have continued undetected.

Think of combustion analysis like a blood test for your heating system. While the equipment might look healthy on the outside, only a proper analysis can reveal what’s happening internally.

Why Proper Equipment and Training Matter

Trying to diagnose combustion issues without the right analyzer is like trying to repair a car without diagnostic tools—you’re simply guessing. Here’s why the right equipment matters:

1. Accuracy: Professional combustion analyzers measure multiple parameters simultaneously: O2, CO, stack temperature, draft, and more—with precision you can’t achieve through other means.
2. Safety: Appliances producing carbon monoxide above acceptable thresholds (typically 200-400 PPM air-free depending on the appliance) need immediate attention. Without proper measurement, you’re leaving your customers at risk.
3. Efficiency: Small adjustments can make significant differences in system performance. The equipment must be running at manufacturer specifications for optimal efficiency, which requires precise measurement.
4. Documentation: When you leave a job, you need verifiable proof that the system was operating correctly. As Tyler Nelson from Sauermann says:

“With combustion analysis, you have proof of the way you left that piece of equipment…something happens after you leave, that’s not on you.” – Tyler

What Makes a Great Combustion Analyzer?

Not all combustion analyzers are created equal. When evaluating options for your business, consider these critical factors:

• Sensor Life: The sensors are the heart of your analyzer and typically the most expensive components to replace. Look for analyzers with long-life O2 and CO sensors to reduce your total cost of ownership over time.
• Measurement Range and Accuracy: Ensure the analyzer can measure the full range of values you’ll encounter in the field. CO measurement capability should handle at least 2,000 PPM, with accuracy within industry standards.
• Overrange Protection: Quality analyzers include features to protect the CO sensor from saturation during high-concentration events like equipment start-up. This prevents damage and extends sensor life.
• Field Serviceability: Consider whether sensors can be replaced in the field or require factory service. Field-replaceable sensors minimize downtime and reduce service costs.
• Connectivity: Modern analyzers should connect to smartphones or tablets via Bluetooth, allowing integration with diagnostic software and easy report generation in the field.
• Calibration Requirements: All analyzers require annual calibration. Consider the cost, turnaround time, and convenience of the calibration process when choosing a device.
• Physical Durability: HVAC work is demanding. Your analyzer should withstand the rigors of daily field use with a rugged design and protective features.
• Battery Life: Ensure the analyzer can operate for a full day of testing without recharging. Look for devices with rechargeable lithium-ion batteries.

Why measureQuick Prefers Sauermann

When Jim Bergmann and the measureQuick team evaluated combustion analyzers to integrate with their software, Sauermann became the clear choice. Here’s why:

1. Industry-Leading Sensor Life: Sauermann analyzers feature 5-year oxygen sensors and 4-5 year CO sensors, offering 50-65% lower usage costs over five years compared to competitors with 2-year sensor life.
2. Intelligent End-of-Life Indicators: Unlike most analyzers that fail without warning, Sauermann’s built-in algorithm monitors sensor performance and warns you well before failure occurs—eliminating unexpected failures on the job site.
3. Programmable Pump Cutoff: This feature protects the CO sensor from saturation, allowing technicians to test during equipment light-off without damaging the analyzer.
4. Manufacturer Responsiveness: Sauermann has been extremely responsive to improvement requests from the field, making firmware updates available over-the-air without requiring unit returns.
5. Software Integration: Both the 030 and 130 models are fully compatible with measureQuick, the only combustion analyzers currently integrated with the platform.
6. Excellent Value: Starting at around $800 for the 030 model, these analyzers deliver professional features at an accessible price point.
7. NCI Endorsement: These are the analyzers that the National Comfort Institute (NCI) uses in their combustion training—a powerful endorsement from the industry’s premier training organization.

Performing Proper Combustion Analysis: Key Steps

We’ve written a measureQuick Combustion Quick Start Guide, which you can download below. At a high-lievel, a proper analysis follows these essential steps:

1. Verify safe levels of ambient CO
2. Start the appliance and check for spillage (for atmospheric draft appliances)
3. Set manifold pressure to manufacturer’s specification
4. Verify correct input (clock the meter)
5. Adjust manifold pressure as needed within allowable limits (3.2-3.8″ WC typical)
6. Perform combustion test
7. Verify adequate draft
8. Verify acceptable temperature rise (set blower speed)
9. Verify maximum CAZ depressurization is within allowable limits

Proper test locations vary by equipment type. For 70% efficient appliances with draft hoods, you’ll test undiluted flue gas in each cell under the draft hood. For 80% and 90%+ equipment, you’ll sample in the vent connector 12-24″ away from the induced draft motor.

Getting Proper Training

While having the right analyzer is crucial, knowing how to use it effectively is equally important. The National Comfort Institute (NCI) offers the industry’s most comprehensive combustion analysis training.

Their courses teach you not just how to take readings, but how to interpret them—how to diagnose problems based on the numbers you’re seeing. They also cover critical safety procedures like worst-case draft testing and CAZ depressurization testing.

What makes NCI training special is their hands-on approach. You’ll work with actual equipment under controlled conditions, learning from instructors with decades of field experience. And it’s worth noting that NCI uses Sauermann analyzers in their training programs—a testament to their reliability and functionality.

The Bottom Line

Combustion analysis isn’t an optional skill—it’s essential for any technician working with fuel-burning appliances. With equipment like Sauermann analyzers and proper training from organizations like NCI, you’ll be equipped to:

• Identify safety issues before they become dangerous
• Optimize systems for peak efficiency and performance
• Reduce callbacks by getting the job done right the first time
• Document your work professionally
• Differentiate yourself as a true professional

As Tyler Nelson aptly puts it,

“If you want to have this be your career and not just a job, use the appropriate tools with the proper technology, do your job correctly, run the analyzer on the system, and position yourself with whatever adjustments you need to make.”

Your customers are counting on you to do the job right. Make sure you have the tools and knowledge to deliver.