Arkansas HVACR NewsMagazine March 2024

HVACR NewsMagazine March 2024

Tech News

up to the airstream for 30-45 seconds as the unit turned on. You won't find that test in any professional guidance because it's not the intended use case for the device.

The Case for Buying a Combustion Analyzer By Matt Bruner for HVAC School For Techs by Techs Last year, I bought my first combustion analyzer. I had just started my own company and felt the additional weight of responsibility to sit down and determine the best way to verify that the furnaces I was servicing were working safely. In the past, the most extensive testing I had done was a visual inspection of the heat exchanger with a camera and an ambient carbon monoxide test with a personal CO meter.

Biting the Bullet

I was reluctant to drop $600-700 dollars on a combustion analyzer. I had just started my business, and we don't do an insane amount of heat work here in Dallas. But I felt I owed it to my customers to provide the highest level of confidence I could that their heating equipment was safe. So, I bit the bullet. I did some research and decided to buy the UEi C161 combustion analyzer. It has a great price point and seemed like a good entry level tool.

Early last winter, I went to a friend's house to complete a heat maintenance and ran into a situation that made me very uncomfortable. I turned on the furnace and held my personal CO meter up to a register (as I had been taught to in the past). The levels rose up to around 8 or 10 ppm, which is the highest I have ever seen.

Back to Work

While my tool was being shipped, I listened to every HVAC School podcast I could on combustion analysis, like this one with Jim Bergmann and this one with Stephen Rardon. I also read this guide Jim Bergmann wrote. A few days after my new tool arrived, I went back over to my

Stunned, I immediately began looking for cracks on the heat exchanger. I wasn't able to find any issues visually, so I reached out to the HVAC School Facebook group. Contractor extraordinaire Michael Housh from Ohio told me I was testing incorrectly and the only way to really know what was going on with the furnace was to get a combustion analyzer. Personal CO detectors are made for just that — personal use; they monitor ambient CO levels but aren't made to test heating equipment. My method of testing was to hold the CO detector

friend's house to use my newfangled tool. I did everything by the book: I clocked the gas meter, checked the gas pressure, and inserted the combustion analyzer into the flue pipe. I took some screenshots from one of the guides as a quick reference to help understand what "good" combustion analysis readings should look like for an 80% gas furnace.