The actuators come in various guises both 230 volt and 24 volt 2-wire and 4-wire, they are a simple on-off device that uses a wax filled capsule that once it receives a signal generally from a room thermostat warms up slowly taking 3 minutes to be fully open.
The actuators are hard-wired to the wiring centre adjacent to the the underfloor heating manifold which receives the command from the thermostat when it is calling for heat to open or once the room is up to temperature to close that circuit down.
The room thermostat can control multiple actuators depending on how many underfloor heating circuits are in that zone, but all work in unison when a command has been received by that thermostat either directly wired to the wiring centre on as more is the case via a wireless thermostat.
Generally the units are such a simple design they last a long time but if the occasion arises then it is a simple matter to replace the unit taking care that you wire in the new one to the same thermostat.
if you need a new actuator then you can visit our website and purchase a replacement by clicking here it will take you to the relevant product.