Ultra-Low NOx Burner Retrofits in California
High-efficiency, ultra-low NOx burners with Autoflame controls or controls from other manufacturers, installed and tuned by McKenna to meet your air district’s NOx limit.
Code-built boilers and vessels
Code repairs and alterations

Factory-authorized Tech Center

Factory-authorized Burner Tech Center
Fifth generation, family-owned
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McKenna Boiler Works, Inc. retrofits industrial boilers across California with high-efficiency, ultra-low NOx burners, as low as 2.5 ppm NOx (corrected to 3% O2) on select models. A retrofit covers the boiler survey, burner selection, air district permit support, installation, tuning, and source test support. McKenna is a factory-authorized Limpsfield Burner Tech Center and Autoflame Tech Center. McKenna also installs, sets up, and tunes burners and controls from other manufacturers, including a brand an engineer or contractor already specified. Family-owned since 1921. Call (323) 987-1816 or email info@mckennaboiler.com.
Why retrofit
Why retrofit instead of replace.
California air districts keep lowering NOx limits on boilers. When the pressure vessel is sound, a new burner and controls can bring it under the limit without replacing the whole boiler.
An ultra-low NOx burner with Autoflame controls, or controls from other manufacturers, holds a tight fuel-air ratio across the firing range, with oxygen trim holding excess air down, so the boiler meets the rule with as little extra fuel as possible.

What’s included
What a retrofit includes.
- Survey of the boiler, burner, fuel train, room, and current permit
- Burner sized to the boiler and the load
- Autoflame combustion controls or controls from other manufacturers, with oxygen trim available
- Gas train and safety controls to ASME CSD-1 or NFPA 85 where they apply
- Air district permit application support
- Startup, tuning, and source test support
Retrofit details
Burner
High-efficiency ultra-low NOx
NOx
As low as 2.5 ppm NOx (corrected to 3% O2) on select models
Controls
Autoflame combustion controls recommended, oxygen trim available. Controls from other manufacturers on request.
Air districts
South Coast AQMD, San Diego County APCD, San Joaquin Valley APCD, Bay Area AQMD, and others in California
Prefer a specific burner?
We’ll give you options
The rules
Air district NOx rules.
South Coast AQMD
Rules 1146, 1146.1, and 1146.2 set NOx limits for boilers by size.
San Diego County APCD
Rules 69.2, 69.2.1, and 69.2.2 set NOx limits for boilers by size.
San Joaquin Valley APCD
Rule 4320 and Rules 4306 through 4308 cover boilers, steam generators, and process heaters.
Other districts
Bay Area AQMD Regulation 9, Rules 6 and 7, plus Sacramento, Ventura, and other districts with their own limits. We check yours before we quote.
2,000,000 Btu/hr or less in South Coast AQMD? Rule 1146.2 sets zero-emission dates: January 1, 2029, in new buildings and January 1, 2033, in existing buildings once a unit is 25 years old, for boilers that make steam or heat water above 180°F (lower-temperature units have earlier dates). McKenna has units pre-certified to the current Rule 1146.2 NOx limits for use until the zero-emission dates apply, and we’ll tell you which path makes sense.
How a job runs
How a retrofit runs.
01
Survey
We look at the boiler, burner, fuel train, and your current air permit.
02
Engineer and quote
We size the burner and controls, confirm the district’s limit, and send a written quote.
03
Install and tune
McKenna crews install the burner and controls and tune them across the firing range.
04
Test and hand off
We support the source test and train your operators on the new controls.
Why McKenna
Why plants use McKenna for retrofits.
Factory-authorized Limpsfield
McKenna is a factory-authorized Limpsfield Burner Tech Center.
Factory-authorized Autoflame
McKenna is a factory-authorized Autoflame Tech Center for combustion controls.
We build boilers
We know what’s behind the burner, because we design and build boilers.
One company
Survey, permit support, install, tune, and service.