We hava an issue with a York RTU (D1CW300N24046FDA) which has a factory installed UNT controlling it. The mixed air and vortex dampers are controlled out of the zone bus of the UNT and don't seem to work.
We have never done any installs using the zone bus for anything so i have limited knowledge.
The UNT has been replaced, actuators have been switched with a functional unit and they work in that unit, and they say the wiring has been verified to have no issues (having them pull a new temporary wire to verify that because it sounds like they covered all the bases already).
Can anyone offer up suggestions on this? The problem started a few months ago with another tech working on it that no longer works here but i'm pretty sure my answer at that point was to call York