Working Principle - Watts valpes VRA Mode D'emploi

VRA and VSA FAILSAFE actuators
Description
Failsafe CSA actuators integrate battery pack monitored by electronic board in the actuator. Its function is to relay in case of
power supply failure on terminal PIN 1, 2 and 3 of the actuator. The failsafe actuators can be set on different position like nor-
mally open (NO) or normally close (NC) depends on customer application.
The electronic board monitors the battery pack and check the status of battery (cycle load and failure). If a battery failure is
detected , a contact on PIN 66 and 66 switch off .If customer use this contact he could be aware that there is a failure on bat-
tery in the actuator without remove cover and plan the replacement.
Failsafe option requiered ON/OFF mode.
Advantages
 All in one: no additional wiring required
 Cost effective
 Battery gauge active 24H/24H
 Power shut off after 2 mn to avoid battery discharging
 Quick and easy replacement of the battery
 2 initial position settings: "normally open" or "normally closed"
 Battery failure feedback relai

Working principle

Please consider 1.5 safety factor (and 2.0 safety factor for POSI version) when sizing the actuator
15