Underfloor heating Actuators problem

Hi all.
Does anyone know much about these actuators that go onto the manifold. The stat tells the actuators to open and close depending on temperature setting in that room..
I'm only new to this. Have air to water heating system in my house . And I noticed few months back heat pump was coming on far too often. And notice one my rooms was cold.
I got an electrician up to replace the actuator. And was grand. Up until about 10 days ago. Same thing happened again. Only this time different room. I got actuator replaced again and seems be okay again.
But my question is as I don't know much about it - Does the actuators stop working for some reason?
It's a new build house with modern heating system only going 15 months.
-Should actuators not last longer than that?
It costs €23 for new actuator. And then to pay an electrician to come out to replace it after that.
No happy at all.
Thanks people