- Hughes Machinery Co.
- J & B Sales Co
- Applied Technologies of NY
- Kissick Engineered Products & Sales
- Louisiana Steam Equipment Company
- Pacific Combustion Engineering
- Mid-State Boiler and Repair
- UM Group, Inc.
- Independent Boiler Works, Ltd.
- Bacon Engineering Limited
- RJ Mechanical, Inc. / RJ Energy Systems
- MavTech Energy
- Enviro Mechanical Sales, Inc.
- Oklahoma Boiler Equipment
- Energy Consortium Ind.
- Combustion Service & Equipment