Water level detector for car IC engine cooling radiator - uses float chamber containing an expanded plastics float with magnet in its base to control reed relay

摘要

The low water level detector for a motor vehicle cooling system uses an expanded plastics float with a magnet mounted in its base to detect the water level in the radiator. A reed relay below the float chamber is open while the float is at the correct level, but closes when the float falls, owing to falling water level, to be near the bottom of the float chamber. The relay has the two reeds connected to separate male push-on terminals which are held in a moulded plug fitted into a boss on the protective outer wall which covers the float chamber. Inside the float chamber a V-shaped ridge runs vertically and prevents sticking of the float caused by the action between the float and float chamber wall.