How to turn an actuator off ?

[JFR123]

Hi. I have underfloor heating controlled by these actuators. One of the behr actuators is stuck on. Can anyone help advise how to turn it off? The newer one on the right is easy to remove and see the pin. The other two don’t seem to have an easy method of removal. Can anyone help?

 

[Knappers]

They will unscrew from knurled ring at base.
Taking off will just leave zone on full, to turn off you need a cap to hold pin down.

 

[ShaunCorbs]

Or a carefully balanced zip tie

 

[JFR123]

Thank you. Right I’ve done this and used some wd40 on all of them. Pins all move ok.

I’ve noticed that when I tighten/loosen the brass valves, it seems to cause the flow of water to start/stop. Do I want to be able to hear water flowing or not? The thermostats are currently all off so there should be no demand being sent. When I press the pin in all the way, this seems to start water flowing as I can hear it hissing inside - should i be replicating this when the actuator head is on by adjusting it until it makes that sound?

 

[Knappers]

Just bolt all the way down.

 

[JFR123]

Thank you.
Looking at the plans I think the issue may be with the new (mohlenhoff) one on the right. The blue top is stuck popped out. Is there an easy way to rectify this? I’m waiting for a heating engineer but he can’t come until Friday.