Metabo Dry-running Sensor Hydrostop - Manual (Page 9)

Hydrostop 2.2
The dry-running sensor may only be used with garden irrigation systems and pond
pumps or similar. It must not be used in liquid food handling installations (drinking
water or drinks).
Note:
Pumps designed for pumping liquids cannot prime air for a prolonged period:
the pumped liquid provides – similar to the oil in an automobile engine – lubri-
cation and cooling. If the liquid is absent the pump can be damaged.
The Hydrostop dry-running sensor prevents a pump priming air. It is installed
in the pump’s discharge line. As long as there is water in the line, the water
pressure is sensed by a pressure-sensing switch, closing the circuit supplying
the power to the pump, and the pump runs. If no liquid is pumped, the spring-
actuated pressure-sensing switch opens the supply circuit, and the pump
stops.
Operating controls
1. Plug
2. Tee fitting,
threaded
3. Sensor enclosure
4. Female connector
5. Push-button