Meet the Team

Meet Our Managers

Marvin Allison - President

Marvin Allison


Class A TACLA licensee with over 17 years of commercial and large residential experience in HVAC and Plumbing systems,  Marvin oversees all operations, service work and PASS (Performance Assurance Support Services) for new construction and retrofit projects.

Bill Seel - Plumbing Division Manager

Bill Seel

Plumbing Division Manager

Master Plumber with over 32 years of experience in service and repair. Bill’s extensive knowledge of hot water heaters and boilers allows Blackall to serve as the state’s factory service representative for two national commercial heating manufacturers.

Rodney G. Thornton

Sales Manager

With over 30 years experience in the mechanical and energy industry, Rodney brings a high level of solution based knowledge to our customers.  While overseeing business development opportunities, Rodney is actively involved in every aspect of the design and implementation of projects designed to reduce overall costs of operation, while streamlining the efficiencies, improving comfort and value of the customer’s property.

His extensive background in mechanical, automation and electrical applications and how they directly impact the overall operation of the facility, provides a road map for an outcome that results in a clearly defined strategy.

Shan Cromeens - Project Division Manager

Shan Cromeens

Project Division Manager


20 plus years of experience in the HVAC trade Holds a Texas Class A contractor’s license Experienced in residential and commercial new construction HVAC projects. Vast experience in retrofit and replacement of HVAC systems, chillers, cooling towers, boilers, packaged units and split systems.Operate and manage the projects division for Blackall Mechanical