Refrigerating and Air Conditioning Pressure and Temperature Controls – Commercial
Automatic, hydraulic bellows actuated, low pressure control for commercial and industrial refrigeration equipment applications, with fully adjustable, user friendly range and differential settings, and tilting mercury bulb switching, in attractive, streamlined heavy, plated steel enclosure and handsome cover plate in stylish green, Minneapolis-Honeywell, Circa 1945.
Features:
Attractive, simple elegant styling with plated steel, bright enclosure, long radius streamlined corners and decorated nameplate cover in green.
A mercury bulb controller, with precision mechanism, it includes calibrated scales for cut-out and differential field adjustment and out-board replaceable and interchangeable bellows. Beautifully engineered, it is enclosed in 3 1/2″ x 4 “x 2″deep 1/16” formed steel box with full, front, access cover,
With miniature, built-in pendulum to help ensure plumb mounting needed for the precise operation of the mercury bulb at designated control point.
Technical Significance:
A sophisticated state of the art automated refrigerant low-side pressure controller of the mid 20th century. Representative of the 1940’s and the new generation of commercial and industrial, refrigeration pressure and temperature controls that came with it – compact, precisely engineered by earlier standards,
They were well supported with installation instructions and service personnel, new for the period
The L series, in its many variations, is well documented in company catalogues and in field instruction sheets, variously dated through the latter 1940’s and 50’s.
The control was made in a number of versions for industrial, as well as commercial refrigeration applications, including farm milk coolers, refrigerated display cases, walk-in coolers and freezer cabinets.
Industrial Significance:
Models with snap action switching, replacing the mercury bulb, were available for applications where vibration and tilting were concerned.
The Minneapolis-Honeywell L control series represented well the mid-century control technology of the times, enabling the development of a vast range of new refrigeration applications by the Canadian refrigeration industry.