3.03-2: Frigidaire 1929 Suction Pressure Regulating Valve

HHCC Accession No. 2006.069HHCC Classification Code: 3.03-2

A suction pressure regulating valve for controlling evaporator temperatures on large integral horsepower, multiplexed, commercial refrigeration systems, where 2 evaporators work at different temperatures, both operating on the same refrigeration system, snap action, for sulphur dioxide or Freon 12 refrigerant, Model SAV, Frigidaire Corp., Dayton, Ohio., Circa 1929

Image Gallery (3 Images)

3.03 Refrigerant Flow Controls - NEC




Frigidaire Corp., Dayton, Ohio.



Serial No.:

8 x 4 x 10 in. h


10 lbs.




Exhibit, education, and research quality, illustrating the engineering design, construction and operating principles of an early 2 temperature suction pressure-regulating valve, designed for integral horse power refrigeration applications.

Patent Date/Number:

From York County (York Region) Ontario, once a rich agricultural hinterlands, attracting early settlement in the last years of the 18th century. Located on the north slopes of the Oak Ridges Moraine, within 20 miles of Toronto, the County would also attract early ex-urban development, to be come a wealthy market place for the emerging household and consumer technologies of the early and mid 20th century.

This artifact was discovered in the 1950’s in the used stock of T. H. Oliver, Refrigeration and Electric Sales and Service, Aurora, Ontario, an early worker in the field of agricultural, industrial and consumer technology.

Type and Design:

Cast brass body with heavy galvanised overcoat Spring bellows and needle operated

Special Features:
Performance Characteristics:
Control and Regulation:
Targeted Market Segment:
Consumer Acceptance:
Market Price:
Technological Significance:

For cost considerations, especially in the era of open refrigeration systems, in the late 1920’s through to the pre World War II years, a popular practice was to engineer multiple, commercial refrigeration, equipment applications, even those operating at different suction pressures, on a single condensing unit. The design of equipment for multiplexed, systems application was a significant part of the evolution of the Canadian refrigeration industry, in a period when condensing units were “open” with costly motors and drives to purchase and maintain.

Industrial Significance:

This whopping 10lb., suction pressure regulating valve tells many interesting stories of the emergence of multiplexed refrigeration system applications in Canada. Suction pressure regulating valves automatically controlled the suction pressure and thence the temperature of the evaporator, while the expansion valve regulated refrigerant flow into the evaporator. This valve, with heavy external brass bellows, could have the assembly removed for service, without opening up the refrigeration system.
This early, snap action design, would have, no doubt, produced a few rocky moments, as the condensing unit tried to respond to instantaneous changes in system loading. The Frigidaire manual warrens that 50% of the system load must be on line at any given time. More sophisticated, fully modulating, suction pressure valve designs would soon follow.

Socio-economic Significance:
Socio-cultural Significance:

G. Leslie Oliver, The T. H. Oliver HVACR Collection

HHCC Storage Location:
Bibliographic References:

Frigidaire, Installation and Service Manual, Products Before 1937, SER.’5M..


CMX02 and CMX04 catalogues, Item R13

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