Quality Control Systems, Inc. Mechanical Contractors Home Our Company Services Projects Contact Us Home QCS has been providing mechanical contracting services throughout the Chicagoland area since 1994. Operating as a union contractor, we focus primarily on commercial and institutional mechanical construction. Scope of Services Include: Boilers Chillers Compressors Cooling Towers Heat Exchangers Pumps Heating Air Conditioning Process Piping Ventilation Maintenance Refrigeration Service Home | Our Company | Services | Projects | Contact Us Quality Control Systems, Inc. Mechanical Contractors Phone 708-304-2200 Fax 708-304-2211