Original heating trade vintage catalog for THE MERCOID CORPORATION.  Main office and plant was located at 4213 Belmont Avenue, Chicago, IL. 

Manufacturers of Automatic Controls for Heating, Air Conditioning, Refrigeration. Equipped with Hermetically Sealed Mercury Switches. Products include DA Pressure and Temperature Controls, Explosion-Proof Cases, Diaphram Controls, Liquid Level Control, Lever Arm and Float Controls, Mercoid Type V Transformer-Relays and Mercoid Type W-6 Relays are featured. Has numerous product images with detailed descriptions, uses, applications, specifications and dimensions provided. Unbound from a large 1946 postwar industrial product designer catalog, this unique old four page technical brochure would display beautifully matted and framed. Awesome cover graphics. A fantastic addition to your vintage industrial heating equipment library.