Belimo Valve actuator #LVKX-24-3

EBEBRATT-Ed

Ok how does it work?

I installed 2 new control valve that came with these actuators. Our service manager was supposed to order them spring return. When I first looked at the wiring connections on the actuator it had 24v + &- and the y1 and y2. no end switch.

So I thought they were wrong . No paperwork came with the valves so I looked them up on line and they showed 2 diagrams.

one diagram is "24 v floating" so 24v common to one terminal on the valve actuator, the 24v hot goes to a spdt thermostat or relay to drive the actuator open or closed. I get that that's easy.

The other wiring diagram is called "on-off" (they do not call it spring return) 24volt common to the actuator the 24 v hot goes through a spst stat or relay then to the hot terminal on the valve with a jumper to the y1 terminal.

I hooked it up "on-off" I tried it and it works!

So my question is the valve drives open, the stat is satisfied and opens so now the only thing connected to the actuator is the 24v common yet the stat drives back to the closed or "fail safe " position. It does have a 'fail safe" switch on it so you can have it fail open or closed.

The only thing I can think of is that the actuator must have a capacitor or something inside that stores enough power so that it will drive to the fail safe position when power is removed.

First time I have seen anything like this that was not spring return