Uponor zone heating control actuators not working

[Psyclist]

Throughout our hotel we have little blue 24v Uponor Actuators on the manifolds. For some reason, some of them don't seem to close fully.

I've been mucking about with a manifold over the last few days trying to work out what's going on as I had a couple of complaints from guests staying in a room who said the radiator was red hot even though they turned their room stat right down. The actuator is being controlled by the room stat. I checked it and it is going up and down with the control. However, I turned all the other valves off with manual controls and even when the room actuator was turned down and supposed to be closed, I can still hear water flowing through the pipework.

The actuators certainly don't seem to be adjustable so I'm wondering what the problem could be.

Could it be that the flow pressure is too high? But then surely the other actuators wouldn't work either. I've tried adjusting the return valve but that seems to make no difference at all other than turning it off. If the actuator is closed and I turn the return valve till I can hear the water flow stop, even when the actuator reopens, it still doesn't flow because of the return valve.

Any ideas?

 

[galavictor]

Hello! I'm having exaclty the same problem with my uponor under floor heating. did you find a solution ?

 

[simond]

The actuators are normally full of wax, if you take the suspect one off have a look at the bit that sits on the manifold valve, if it is waxy, you need a new actuator.

Other than this it will be the water valve insert not fully shutting, usually because of sludge contamination from other parts of the system.

 

[galavictor]

I did a quick test yesterday, I removed the actuator completely, then used a small bracket to push and hold the little knob on the manifold valved. In theory that should shut the valve insert completely, but still - water was flowing and rooms were heated. I tried tried with another zone and had the same issue - I was unable to turn the heating off. Could this be a faulty manifold?