Honeywell VC80 valve actuator

JoeC

Have inherited a thermal mixed injection system and the 3 zones are controlled by Wirsbo 2-wire T-stats, a Taco ZVC-403 control panel and Honeywell VC80 actuators. Found all three valves in Open position, they never closed. Suspected that the motors might be siezed, so replaced one actuator. When I produced a call for heat, the valve opened fine, but once the t-stat was satisfied, only the pumps shut down, the actuator valve stayed in the open position. All three valves are in what appears to be an 'open' position, and when any one of the t-stats call for heat, all three zones circulate, warming the building to extremes no less. The actuators are obviously not motoring to a closed position. (Like a three-wire zone valve and a two-wire t-stat situation)Are these three components capatible? I'm curious as to how only two wires from the zone control can produce both open and close signals to the actuator motor.... Thanks!

Alan R. Mercurio

Joe

Check out this link. I think it might be helpful to you.

http://hbctechlit.honeywell.com/techlit/PDF/95c-00000s/95C-10920.pdf

Your friend in the industry,

Alan R. Mercurio

Oil Tech Talk

BillW@honeywell

VC actuator

Alan is right, the literature will show you all the wiring diagrams. The VC80 is a two wire, SPST, two position actuator, and may or may not have an endswitch.

JoeC

Thanks!

Thanks for the responses. I'm sure that a wiring problem exists, just need access to some diagrams. I'm amazed that the building owner has put up with the problem for almost three years now. The installer also failed to trap the bridges which can only be fixed by draining down about 100 gallons of anti-freeze solution.