Fig. 41.—The effect of accumulation of air in a hot-water radiator with bottom connections.
Fig. 42.—With this method of connections, if the air collects sufficiently to force the water down to the level L, circulation will stop.
In Fig. 42 a much different condition exists, when air accumulates. In this mode of connection the water enters through the valve V, and escapes at the bottom of the opposite end. When air fills the radiator to the line L, the circulation is stopped and the radiator will grow cold.
The position of the valve on these radiators is of little consequence. The valve is intended merely to interrupt the flow of the water and may occupy a place on either end of the radiator with the same result.
Hot-water Radiators.
—Radiators for hot-water heating are most commonly of cast iron and in appearance are the same as those used for steam heating. The only difference in the two forms is in the openings between the sections. Those intended for steam have an opening at the bottom joining the sections; while those for hot water have openings at both top and bottom to permit circulation of the water.
Fig. 43.—The hot-water radiator valve.