You're reviewing a subcontractor GA during an AHU install and you literally typed into Google: "HVAC P&ID chilled water control valve symbol normally open or closed". The P&ID shows a chilled water control valve tagged CV-201 with a fail-open actuator symbol, but the valve schedule lists it as fail-closed. During loss of air, what actually happens at the coil?

Question

Accepted Answer

The P&ID symbol shows intent, not hardware truth. The schedule conflicts, so you don't know spring direction. A assumes drawings override hardware, they don't. B assumes a default that doesn't exist across vendors. D confuses electric actuators with pneumatic spring return units.

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