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.

Randy Chandler - Residential Division Manager

Randy Chandler

 Residential Division Manager

Specializing in Residential Sales and service, Equipment Replacement, New Construction, and Remodels, as well as Light Commercial. Randy holds a Class B TACLB license with over 30 years of experience in the Dallas HVAC industry.

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