7.01-3A: Kelvinator 1931 Automatic Temperature Control

HHCC Accession No. 2006.007HHCC Classification Code: 7.01-3A

An early, adjustable, hydraulic bellows actuated control, totally enclosed in 1930’s, modern Bakelite housing, senses evaporator surface temperature, Model R, made for Kelvinator, by Ranco, The Automatic Reclosing Circuit Breaker Co. Columbus, Ohio [A.R.C.B. Co], Circa 1931.

One of a rare matched set of six Ranco Model R controllers profiling the evolution of this early self-regulating temperature sensing electric motor control device, likely over several years from 1929 through to the early 1930’s. The set profiles: 1) the progressive design modifications made to improve performance, 2) design adaptations made as required for different models and styles of Kelvinator cabinet refrigerators, 3) different approaches to user friendly and convenient manual temperature setting by the householder, 4) the application of different mounts and accessories, 4) something of the expected life expectancy of the technology in use, 5) the often precipitous modes of failure, anticipated by the refrigeration service man of the period, and 6) various stages of physical deterioration, as a result of natural use, misuse and abandonment. See numbers 7.01-3A, B, C, D, E, F. ID # 131 to # 136

Image Gallery (2 Images)

7.01 Refrigerating and Air Conditioning Pressure and Temperature Controls - Household


For Kelvinator, by Ranco


Ranco, The Automatic Reclosing Circuit Breaker Co. Columbus, Ohio [A.R.C.B. Co]


RA-10 [see note #1]

Serial No.:



3’ dia. x 7’ long






Exhibit, education, and research quality, illustrating the remarkable engineering advancements made in half a decade by pioneers such as Kelvinator in the design and construction of compact, totally enclosed controls using then modern Bakelite, dielectric material construction.

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:

See Operation

Special Features:

Chrome plated, push-pull, control arm, with Bakelite handle
See Items 7.01-3 B to G for design and application variations involving special features

Performance Characteristics:

The Model R, like the much larger and earlier Kelvinator Model E, is actuated by a bellows immersed in a freezing solution. Bellows and chamber have now been miniaturised, by comparison with the E, and the chamber fully sealed.

Also like the Model E, the bellows is charged with sulphur dioxide. As a result the service mechanic was advised to store un-used controls in a shop refrigerator, in order to reduce the strain on the bellows.

Control and Regulation:
Targeted Market Segment:
Consumer Acceptance:
Market Price:
Technological Significance:

The Model R series thermostat represented a remarkable engineering achievement in 6 or 7 years. A compact design, totally enclosed control, crafted in, then, modern two tone, Bakelite, dielectric material. One third of the size and weight of the Kelvinator E, it was a user friendly, fully adjustable thermostat.

Industrial Significance:

The thermostat also marks the early entrance of the Ranco name into the refrigeration and air conditioning temperature control business, supporting the major equipment manufacturers of the period. The Ranco name would survive for many years as a leader in the HVACR control field.

Socio-economic Significance:

The streamlined design of the thermostat, executed in polished, two tone, brown and back Bakelite, clearly styled to present a pleasing modern look - a break with the past.

Socio-cultural Significance:

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

HHCC Storage Location:

On display HRAI Head Office Jan. 2004 Removed Oct 2006 Restocked Jan 2007

Bibliographic References:

Kelvinator Parts List, Reconstructed, 1931-1932, Kelvinator of Canada, London Ont.


Kelvinator of Canada, London Ont. shows in their November 1932 parts list the Model R series thermostat in 10 different configurations, variously used on their household and commercial cabinet refrigerators from 1929 through 1931. A range of variations were engineered to adapt to various evaporator designs employed on their cabinet refrigerators over several years, see Kelvinator Service manual Form 3410, issued May1, 1929 See Items 7.01-3B to7.01 to 3G for design and application variations See history of Ranco in Ranco Manual 1058, July 1947 and 1058, Nov 1960, in collection, up-date 070111

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