Pressure independent balance and control valve issue

[lucaspenalva]

I have a system with several fancoils with pressure independent balance and control valve (IMI HYDRONICS TA FUSION-P 50)
However, some of them are showing strange behavior:
In automatic mode, at some point during operation, even though valve actuator is fully open there is no flow, so temperature rises and no heat exchange occurs.
However, when in manual mode and fully open, this doesn't happen.
We've replaced the valve but problem still continues.

Any thoughts?

 

[moideen]

lucaspenalva : are you sure the control voltage is generating during the auto mode? i think it is related with control supply to open the valve.