Skip to Menu

Central Boiler

(choose from the list below)

Main article


BOILERS are enclosed vessels in which water is heated and from which it is circulated, either as hot water or as steam.

Manufacturing started in Montreal

1. Image of a Spence boiler from 1883

1. A Spence design from 1883.
Click the image for more information.

Canada’s automated heating industry’s impressive history began when the first hot water and steam boilers were produced on the eve of the country’s first birthday! It was in Montreal, in 1866, when the first Beehive hot water boiler was produced at Rogers & King. The Beehive was soon joined by the Gem and Spence, which were designed by an engineer named Archibald Spence. Boiler production began in Toronto, Ontario in 1883 and in Halifax, Nova Scotia in 1884. Boiler manufacture helped Canada offset imports. Models were shipped to at least six countries.

In 1886, Spence designed one called the Daisy. Like many boilers of the period, its innocent sounding name was given to allay fears that boilers under pressure were not safe. One advertisement of the day comforted potential customers by likening a boiler to “the tea kettle on the kitchen stove.”

Boilers were being manufactured in Europe for the steam engines driving the Industrial Revolution many years before Canadian companies started to build them. Initially these were big tanks of hot water for steam. Engineers and inventors like James Watt gradually advanced the technology and smaller residential models were developed. European immigrants transferred that knowledge and skill to North America where plentiful supplies of wood and coal enhanced this evolution.

Boilers first began as gravity-fed thermal units, because heated water and steam flow naturally from areas of higher temperature to areas of lower temperature. That principle of physics still circulates these hot fluids, but flow is now directed by pump pressure. Fire tube models use hot gases flowing through tubes to heat the water in which the tubes are immersed. Water tube models do the opposite, heating water flowing in tubes immersed in the gases, also heated in the combustion chamber. That is based on the principles of heat transfer from exhaust flue gases. Combustion fuel was from wood or coal, oil and then gas burners, another step in automating systems, or combinations, in both low and high pressure designs. Most early models were of cast iron including the radiators in each room still in use today, or steel.

Section Gallery

2. Image showing a team of horses pulling a boiler across the prairies3. Diagram of an hydronic system4. Image of a Pluto boiler from the early 1890s5. Diagram showing circulation of a hot water system

Factually Speaking

One of the earliest boiler designs was called the "haystack." Mechanically weak, these boilers exploded frequently, usually beginning with failure of the firebox plate.

Technical advances fixed steam problems,
but it still lost the residential markets

Steam heating was considered possible by engineer Sir William Cook in 1745. But it was 25 years before James Watt developed the steam engine and steam heating developed and became possible by 1790, and evolved over the next century.

Early systems delivered steam by gravity from boilers through single piping to iron radiators. With hot steam and return condensed steam as water flowing in opposite directions within the same pipe, water hammer, slow heat recovery, and water under pressure spurting from the air valve sometimes resulted.

The two-pipe two-valve gravity system avoided that problem. Instead, steam would fill the first radiators and flow out the condensation line and instead on to the next radiators. With supply steam still flowing through inlets on all radiators air became trapped, unable to escape via the air vents on the radiators, slowing heat recovery.

1. Diagram showing a two-pipe, two-valve heating system

1. The two-pipe, two-valve heating system.
Click the image for more information.

The fluid-activated thermostatic trap, around 1900, solved these gravity circulation problems in low pressure systems eliminating the whistle, spray, and smell of the air trap, as well as water hammer. Often called vapour heating systems, automatic return traps and condensation pumps were added to them to increase steam pressures.

Vacuum return lines with a vacuum pump had became popular by the mid-1920s to maintain steam heat output. However, this approach lacked control for reducing steam supply during the 95 percent of heating seasons when less than maximum supply was needed, keeping pressure and heat up unnecessarily. Intermittent operation, combustion control, and radiator flow control solutions were tried.

Then came the differential, sub-atmospheric pressure, vacuum heating system in 1926. It featured progressive reduction in steam temperature or steam volume to reduce supply heat output by automatic control valves at the radiator and other control methods.

The industry’s engineers have continued to find new solutions to steam and hot water system problems. Controls and related components shrank as more compact mechanical-, electronic-, and microcomputer-based components were developed. But the problems discussed in this article, coupled with issues of safety, effectively steam heating away from homes to the commercial-institutional sector where standards of supervision and control are mandatory.

Section Gallery

2. Steam versus water or air3. Image of a cast boiler4. Image of the “Canadian Water Boiler”5. Image showing how to connect verticle and horizontal storage tanks6. Image of a gas-fired steel boiler

Factually Speaking

In the early 1900s manufacturers pushed to introduce steam heating systems to residential dwellings, but the complexity of the technology, the noise, and fear of explosions, meant most homeowners opted for hot water or "hydronic" systems instead. Source: Bernard Nagengast

Innovations resolve boiler vexations

1. Cutaway view of the “New Star” 1930 hot water boiler

1. Cutaway view of the “New Star” 1930 hot
water boiler. Click the image for more information.

Enterprising foundries, like O. Belanger Enrg. in Montreal, Quebec helped to advance circulation of hot water in boilers, in their case with their “Syphon Injector.” Balancing heat throughout a home was problematic with gravity flow pushing hot water up but not always still hot when flowing down. That left lower floor radiators cooler than upstairs. This “was very difficult to overcome and gave rise to many vexations, disappointments and disagreements,” the company’s 1930 New Star boiler catalogue stated.

The Syphon Injector increased the speed of water circulation in coils of the lower stories by the speed of circulation in coils of the upper stories. “This important invention works admirably and gives great satisfaction.”

Another advancement in technology by O. Belanger reduced the possibility of breaks in the water sections. “Inventors have been trying hard to improve upon ... their durability by scientific construction to withstand the expansion and contraction of the metal without undue strain ...”

“[A]fter several years of permanent studies, tests, and experiments, we have succeeded in making a [hot water] Section which is unbreakable. This Section was patented in May 1896; thousands have been put up since without a single break,” the company claimed, and with greater surface area has come improved efficiency.

These hot water sections “are made in a series of hollow concentric cast iron rings connected at a single point at the back of the furnace. These rings, independent of each other, will expand more or less and stand the various changes in temperature without any danger of breaking.” One pattern has rings of a different diameter to the other, and when set in above the fire pot fit into spaces in the next ring, and so on. The heat is compelled to travel from right to left, and vice versa, through the section flues many times before the hot gases are exhausted.

Section Gallery

2. Image of a New Star boiler used to heat water tanks

Factually Speaking

Henri Gifford developed the first siphon injector in 1858 for steam trains. The technology speeds up gravity flow and was adopted by boiler manufacturers.

Regulation brought safety to comfort

1. Image showing a steam locomotive after its boiler exploded

1. Railways were early adopters of boilers.
Accidental explosions like this were not
infrequent in the 1800s. Click the image for
more information.

Self-regulation by a responsive industry or imposed regulation by concerned governments has played a major role in ensuring the safety of heating systems for homes and industry. The boiler industry is a prime example.

Steam and hot water heating equipment are complex technologies. Inventors of boilers from the late 1700s onward had to understand the principles of mechanical and electrical engineering, thermodynamics, combustion, heat transfer, material capabilities, chemical properties, and many other related factors when developing these new heating appliances. Those who ignored or misunderstood these realities sacrificed safety with often spectacular and lethal results.

From the mid-1800s to the early 1900s, boiler explosions were common on land and sea. ASME, American Society for Mechanical Engineers, founded in 1880, reports on its website:

“The Society is best known ... for improving the safety of equipment, especially boilers.” From 1870 to 1910, at least 10,000 boiler explosions in North America were recorded.

By 1910, the rate jumped to 1,300 to 1,400 a year. Some of the larger accidents motivated public calls for remedial action. A Boiler Code committee was formed in 1911 and the Boiler Code was published in 1914-15, and later incorporated in laws of most American states and territories and Canadian provinces. The Uniform Boiler Law Society supported the ASME Code and organized the Uniform Boiler Congress in 1916. Several Canadian provincial boiler inspectors participated. The result was the formation, on December 2, 1919, of the National Board of Boiler and Pressure Vessel Inspectors, with Canadian chief inspectors on its board of directors.

This North American standards organization has stated it has been “a sentry for the public trust” in boiler inspection and quality control for more than 90 years. Its goal is “to promote safety to life and property through uniformity in the construction, installation, repair, maintenance and inspection of boilers and pressure vessels.” Training and education is a major responsibility. Registration of all ASME boilers was a first step, along with its inspection stamp, to track all boilers made.

Section Gallery

2. News story about a woman who died when she tried to ignite a gas furnace3. Article about a woman who jury rigged a way to get gas to her furnace

Factually Speaking

In 1933 an instrument was developed by O. Millhauser that used sound waves to detect imperfections in the metal used in boiler welds.

Reliable, automatic, combustion safety control

1. Image of a Locksmith magnetic relay

1. The “Locksmith” magnetic relay would start the
oil burner on a call from the living room
thermostat. With a signal from its companion
“Stackswitch,” it would also shut the oil burner
down under unsafe conditions. Click the image
for more information.

2. Image of an  automatic thermal switch that monitored the oil burner

2. The Stackswitch consisted of a stack-mounted,
helical, thermal sensor which detected whether
the oil burner had fired properly. If not, it would
shut the burner down before dangerous amounts
of oil vapour entered the combustion chamber.
Click the image for more information.

With the introduction of “Locksmith” combustion safety controllers Canadian home owners would have available a compact and reliable combustion safety system. This system, a creative and truly advanced engineering concept for its times, consisted of a stack-mounted thermal sensor and a switching device with safety interlocks. It would stop and start an oil burner on call from the room thermostat — and most important, shut it down in case of misfire or other mishap.

With combustion safety devices of increasing sophistication and reliability the public’s confidence and trust in automatic central heating equipment would increase rapidly, so it was hoped. The central automatic home heating market was a substantial one, yet dependent on the industry’s ability to deliver safe and reliable products, at a price middle class Canadians could afford and believe in.

Section Gallery

3. Image showing the internal workings of the “Locksmith” electromagnetic relay4. Blow-up view of the mercury bulb safety switch5. Blow-up view of safety lockout mechanism

6. Image of a Stackswitch showing the helical, bi-metal, temperature sensing unit7. Stackswitch showing mercury bulb switch8. Stackswitch showing mercury bulb switch mounted on the end of its rotating shaft

Factually Speaking

Steel boilers will deliver much higher heat ratings than cast iron, based on the area of the heating surface or weight.

Multiple fuel changes typical
of 20th century consumer demand

1. Image showing old and new boilers, side-by-side

1. Old and new boilers, side-by-side. Click the
image for more information.

The heating system in the Spadina Museum Garage and chauffeur’s residence in Toronto demonstrates a typical evolution of heating technologies in southern Ontario, Canada during the past 100 years. Because of the preservation of many elements of the system, dating right back to the initial installation in 1912, this is a great example of technological adaptation to changing market forces and consumer demand.

The initial installation of a two-pipe, steam hydronic system was presumably state-of-the-art for 1912, designed as it was for a prominent landowner undertaking major capital property upgrades with a view to recognizing and incorporating the latest technological innovations.

As technologies within the heating industry evolved, the change-over to a hot water system from steam was probably mandated by consumer demand for more consistent and reliable indoor temperature control during Canada's cold winters. Consumer demand again likely drove the conversion of the initial coal-burning system to an oil-fired burner, bringing a cleaner and less labour-intensive lifestyle. Much of southern Ontario underwent this same change during the 1940s and 1950s.

Increasing costs for oil, especially during the 1970s, together with the completion of the Trans-Canada natural gas pipeline (during the 1950s) changed the economics of home heating in this country. Economic pressures eventually mandated the conversion of oil-burning to natural gas-fired systems for many Canadian homes, and this dwelling was no exception.

Finally, the late 20th century demand for energy efficient heating and containment of continuously escalating costs likely explains the installation of a new, high-efficiency gas furnace and abandonment of the old cast-iron boiler. None of the change-over dates have been recorded by the museum.

Section Gallery

2. Photo of a pressure/temperature gauge mounted on an old boiler

Article Sources

Manufacturing Started in Montreal

  • Business and History — Warden King Division of Crane Canada Limited | Western Libraries, via (accessed January 21, 2010).
  • Air conditioning and refrigeration : a complete training program, Series C: Heating--Part1 (Chicago: Refrigeration and Air Conditioning Institute, Inc., 1938).
  • James Morrison Co., Illustrated Catalogue and Price List ... (Toronto: R.G. Mclean, 1888) — First boilers produced in 1886, c/o Hugh Palser, President Palser Enterprises, London, Ontario.
  • James Watt — Wikipedia, the free encyclopedia, via (accessed February 1, 2010).

Technical advances fixed steam problems

  • Research from the archives of the HVACR Heritage Centre Canada (DCSB #37, HD1005Z).
  • C.A. Dunham Co., Ltd., The Dunham Hand Book,” No. 514 (Toronto, Ontario: n.p., mid-1930s), 432 pages. Lewis-Langsner Archive Collection, Montreal, Quebec, HVACR Heritage Centre Canada Collections.
  • HVACR Heritage Centre Canada Founding Collections, T.H. Oliver Archive Collection.
  • Taylor-Forbes Co. Ltd., 55R Hand Book of Sovereign Radiators and Boilers, (Guelph, Ontario: n.p., 1912), hard cover, 108 pages. Lewin-Langsner Archive Collection, Montreal, Quebec, HVACR Heritage Centre Canada Collections.
  • Dominion Radiator Limited, Dominion Ideal Fitter (Toronto, ON: n.p., 1951), c/o Lewis-Langsner Archive Collection, Montreal, Quebec, HVACR Heritage Centre Canada Founding Archive Collection.
  • “Steam circular radiators,” in James Morrison Illustrated Catalogue, 1888, Toronto, Ontario, c/o Hugh Palser Collection, London, Ontario.

Innovations Resolve Vexations in Boiler Technologies

  • Research from the archives of the HVACR Heritage Centre Canada (DCSB #40, HD1005CC).
  • O. Belanger Reg., Catalogue and Price List for “New Star” 1930 Hot Water Furnace (Montreal, Quebec: n.p., 1930).
  • U.S. National Park Service - Experience Your America, via (accessed June 20, 2011)..
  • www.baumanns.ei.

Regulation brought safety to comfort

  • Research from the archives of the HVACR Heritage Centre Canada (DCSB #20, HD1005E).
  • The National Board of Boiler and Pressure Vessel Inspectors, via (accessed August 9, 2010).
  • “A Brief History of ASME — ASME History.” American Society Of Mechanical Engineers — ASME.ORG, via (accessed August 9, 2010).

A reliable, automatic, combustion safety control system

  • Research from the archives of the HVACR Heritage Centre Canada (DSCB #30, HD1005R).
  • Historical artifact from the HVACR Centre Canada T.H Oliver Collection Accession No. 2006-104/105.

Multiple fuel changes typical of 20th century consumer demand

  • Research from the archives of the HVACR Heritage Centre Canada (DCSB #60, HD1006S and DCSB #35, HD1005X).
  • HVACR Heritage Centre, site documentation, 2007, by Dave Barr, Toronto.
  • Full story at:


  • Research from the archives of the HVACR Heritage Centre Canada.
  • Business and History — Warden King Division of Crane Canada Limited | Western Libraries, via (accessed January 21, 2010).
  • Bernard Nagengast, An Early History Of Comfort Heating, Air Conditioning, Heating and Refrigeration NEWS, via (accessed Jan 6, 2011).

Factually Speaking

  • Research from the archives of the HVACR Heritage Centre Canada.
  • Bernard Nagengast
  • Dr. Andrew Ure: Pioneer Free Trader | The Freeman | Ideas On Liberty, via

Image Credits

Manufacturing started in Montreal

  • 1893 Clare Bros. and Co., Descriptive Catalogue (Guelph, ON: Jas. Hough, 1893), 93. Print.)
  • Glenbow Archives, NA-5257-35 [detail].
  • No source.
  • 1893 Clare Bros. and Co., Descriptive Catalogue (Guelph, ON: Jas. Hough, 1893), 93. Print.)
  • Old House Web, via

Technical advances fixed steam problems, but it still lost the residential markets

  • Dominion Ideal Fitter, vol. 1 (Toronto, 1951), 47.
  • Clara E. Laughlin, ed., The Complete Home (New York: D. Appleton And Company, 1907), 71.
  • Weil-Mclain Company, Michigan City, Indiana.
  • Taylor-Forbes Co., Ltd., Catalogue No. 55R (Guelph, ON: n.p., 1912).
  • The Dunham Handbook No. 514 (Toronto: C.A. Dunham Co., Ltd., 1936), 15.
  • Bryant Heating Co.

Innovations resolve vexations in boiler technologies

  • O. Belanger Reg., Catalogue and Price List for “New Star” 1930 Hot Water Furnace (Montreal, Quebec: n.p., 1930).
  • Ibid.

Regulation Brought Safety to Comfort

  • Source unknown
  • The Globe, Toronto, 20-06-1923.
  • The Globe and Mail, Toronto, 05-02-1959.

A Reliable, Automatic, Combustion Safety Control System

  • HHCC Historical artefact (Accession No. 2006-104/105), photographed by Mark Dorlandt Photography, HD1006A-17-003.
  • Ibid., 013.
  • Ibid., 17-005.
  • Ibid., 17-009.
  • Ibid., 17-010.
  • Ibid., 18-015.
  • Ibid., 18-021.
  • Ibid., 18-022.

Multiple fuel changes typical of 20th century consumer demand

  • Spadina Museum Garage, HVACR Heritage Centre, via
  • Ibid.