Mechanics of the Household / A Course of Study Devoted to Domestic Machinery and Household Mechanical Appliances

by E. S. Keene

Fig. 43a.—Details of construction of the hot-water radiator valve.

Hot-water Radiator Valves.

—Valves for hot-water radiators differ materially from those used on steam radiators. Figs. 43 and 43a show the outside appearance and the mechanical arrangement of the parts of the Ohio hot-water valve. The part A in Fig. 43a is a hollow brass cylinder attached to the valve-stem, one side of which has been removed. When it is desired to shut off the supply of heat the handle of the valve is given one-quarter turn and the part A covers the opening to the inlet pipe. The supply of water being shut off, the radiator gradually cools. When the valve is closed a small amount of water is admitted to the radiator through a ¹⁄₈-inch hole in the piece A to prevent the possibility of freezing.

Air Vents.

—In the use of the systems of hot-water heating described, every radiator must be supplied with an air vent of some kind to take away the trapped air which accumulates through use. Any kind of a valve will serve as a vent for hand regulation and generally such a cock as is shown in Fig. 10 is employed.

Fig. 44.—Automatic air vent for hot-water radiators.

Automatic Hot-water Air Vents.

—It is sometimes desired to use automatic air vents on hot-water radiators. For such work a vent is used that remains closed as long as water is present and will open when the water is displaced by the accumulating air, but will again close when the air is discharged. In such vents the valve is controlled by a float, the buoyancy of the float when surrounded by water serving to keep the valve closed. These vents are not so positive in their action as automatic air vents for steam. The change in temperature which controls the steam vent does not take place with hot water. The automatic hot-water vents are not perfectly reliable. They may work with entire satisfaction for a long time and then fail from very slight cause. The failure of a hot-water vent is generally discovered by finding a pool of water on the floor or a wet spot on the ceiling or wall of the floor below.