Water limiter in heating systems

The AFRISO WATCHDOG boiler water low level alarm WMS monitors the water level in heating systems as per EN 12828. If the water level drops below a minimum level, WMS triggers an alarm and the boiler is switched off. The complete WMS boiler water low level alarm consists of a control unit and a probe, which are connected by means of a twocore signal cable with a maximum length of 50 m. The control unit is supplied with AC 230 V. It contains all display and control elements as well as a voltagefree output relay for transmitting the signal, for example to an alarm unit or event reporting systems. WMS is failsafe and selfmonitoring; in addition to low water levels, it signals wire breaks or errors in the probe circuits. WMS is suitable for ambient temperatures of 0 °C to 55 °C, for heating water temperatures of up to 120 °C and for water pressures of up to 10 bar. The WMS boiler water low level alarm is available in various versions: With internal power failure lock (after a power failure, the control unit must be reset) or with an external power failure lock (the control unit is automatically reset after a power failure). A button (normally open) may be connected at a distance of up to 200 m to the control unit for external resetting. The probe is available in 2 versions: The probe version DN 20 with angular brass housing and a plastic housing top with an electrode rod that can be pulled for testing the function of the unit. DN 20 features two welding sockets (DN 20) for installation. The probe version R 2 has an electrode housing made of galvanised steel and a threaded socket (R 2 male thread) for screw connection. The WATCHDOG boiler water low level alarm WMS is easy and quick to commission and has the following certificates: TÜV HWB 04-345 and TÜV HWB 04-348.