Introducing O.H. “Fletch” Fletchall

Mr. O.H. “Fletch” Fletchall was a steel designer working with Aetna Steel Company of Jacksonville designing heating systems for fuel transport barges during the Second World War and had to routinely visit Mr. Dick Illingworth to gather structural information on boilers.

Don Fletchall & Chester Fulkerson, Jacksonville April 1971

He and Mr. Illingworth developed a close friendship and in April 1945, Mr. Illingworth offered Fletch a position with Illingworth Engineering, Inc., one of the first generation of Cleaver-Brooks representatives. When Mr. Illingworth passed away and Fletch continued the operations of the company.


His sons, Jerry and Don Fletchall, joined their father in the business as Sales Engineers in 1958 and 1961 respectively. Illingworth’s region at that time covered South Georgia, North and Central Florida.

Don & Hugh at CB 50 Year Anniversary 1979


On January 1, 1984, Don split from Illingworth and partnered with Hugh Wilson to incorporate Thermal Tech, Inc. with the corporate office located in Tampa and an office in Winter Park. The company grew from a couple of two man offices to approximately 15 employees in the mid-1990’s.


Co-Founder/President Don Fletchall

In 1986, Deron Keiter was recruited by Mr. Wilson as a Service Technician and relocated to central Florida. Deron advanced to Aftermarket Sales in 1991. Rick Wilkins joined the sales team in Tampa 1994 after 10 years’ experience with Fluor Engineers in South Carolina.

In February 1997, after leading Thermal Tech, Inc., Don Fletchall retired and corporate headquarters transferred to Hugh Wilson in the Orlando office. At this time Deron and Rick were given the opportunity to become partners in the corporation and joined the management team.

Hugh Wilson, Rick Wilkins, Deron Keiter

In 2002, Mr. Wilson began planning the succession of the company and formed an ESOP to reward the employees with ownership in the company. The resulting ownership is with the Thermal Tech, Inc. ESOP Trust, Mr. Keiter, and Mr. Wilkins.


In 2022, Thermal Tech Inc. acquired Illingworth Engineering Company from the grandson of O.H. Fletchall.

Thermal Tech Inc’s expansion stretched its Southeast territory into North Florida (Jacksonville) and South Georgia (Thomasville), totaling 4 offices for Thermal Tech Inc.

Authorized Cleaver-Brooks Representative

Proud Member of the Cleaver-Brooks Representatives Association

Thermal Tech Inc. has been really good to us over the years. They helped us with an upgrade conversion from fuel oil to natural gas on our Cleaver-Brooks steam boiler. This was a huge saving in our overall expense for fuel and dependability. They have the best service tech’s and are very knowledgeable. The fact that they are 24/7 has pulled us out of plenty of jams. Overall, the customer service is hands down! They are our boiler people.

Plant Facility Manager, Savannah GA