Heating System in the Garage Building

The garage is heated by a hydronic system, with a boiler in the basement and a series of radiators on the ground and second floors. The boiler is located near the east end of the half basement, lying beneath the northern half of the building, close to the chimney. There is a wall thermostat near the front entrance on the ground floor and the expansion tank is located at the end of a blind hallway on the second floor.

Although a high efficiency, gas-fired boiler was recently installed (about 2004), the original boiler has not been removed, allowing an appreciation not only of the original heating system, but of some of the modifications

The original boiler is a Severn cast iron, upright, coal-fired sectional boiler manufactured by American Standard. In this installation, 3 1/2 sections were used, clamped together with upper and lower tie rods on either side. The dimensions of the boiler proper are: width 25″ at base (22″ at top), height 48″, and depth 29″.

The boiler is rated for both steam (max. 15 lb.) and hot water (max. 30 lb.). From the dimensions and construction of the headers, the system was evidently first used for steam heating. As a two-pipe steam system, this was an advanced installation for 1912, and probably more expensive than the earlier and less effective one-pipe systems.

The old and new boilers, side-by-side
Pressure/temperature gauge mounted on the old boiler. ASME St’d., Marshalltown

The modern, high efficiency system has a water pump, but there is no evidence of a pump component in the earlier hot water system.

A second modification in all likelihood converted the boiler from coal burning to oil-fired. No evidence of the oil burner remains, but we do have the final modification to gas, with the insertion of an Economite (Model E20, Mid-continent Metal Products Co).

This front view of the cast iron boiler showing the three original access doors: boiler pipes (top), fire box (center), and ash removal (bottom). Each door is provided with a heat-dissipating coiled steel handle.

The top door is sealed with furnace cement, but the fire box access door is currently secured with a spring and can be opened. The bottom door, of course has been secured and pierced to admit the Economite gas burner.

Detail of gas burner insert into the old boiler.

View of the top of the old boiler.

Several photographs provide a good idea of the elements of the heating system installed in the basement.

On top the 5″ diameter iron steam supply header can be seen, as well as the top right tie rod and at the back corner, the relief valve. Attached to the steam supply header is a Honeywell aquastat thermostatic control.

The east wall of the basement and the four main, manual steam control valves can be seen.

Below are two views of the right side of the old boiler. The full extent of the steam supply header can be seen here as well as the condensate return pipes and the condensate return header leading into the bottom of the boiler at the rear. The remains of the flue stack and soot clean out are also visible at the back of the boiler. The black, two-inch piping near the wall is part of the later hot water system.

Radiators in the residential areas of the garage (second floor) are of the conventional, cast-iron type.

There are a total of 13 radiators, of varying sizes and designs, located on the ground and second floors.

The expansion tank in the garage is on the second floor, near the top of the system.

Detail of manual heat control valve for a floor radiator.