Engineering notes
Solenoid or modulating: two different orders
A solenoid is open or shut. A modulating valve takes 0–10 V or 4–20 mA. Mix them on an AHU branch and the room hunts.
The drawing says “control valve”. Stores issue a 230 V solenoid because it is cheap and on the shelf. The AHU needs water with load — the valve only knows full open or full shut. Room temperature hunts, the chiller steps. If the consultant wrote modulating, you need a characterised valve and an analog actuator.
Solenoids are fine for isolation, drain, some on/off FCUs. Modulating belongs on AHUs and main chilled-water valves with a PID loop. Valve voltage must match the cabinet — 230 V into a 24 V module cooks the output.