Title: Siemens STA73-eng.pdf
NO function • STA.. actuator stem is extended when de-energized.NC valve required.NC function • STA.. actuator stem is extended when de-energized.NO valve required.Note NO function (Normally Open)The valve is closed in a de-energized state for most valve applications featuring thermal actuatorsActuators with the opposite control action, are used when the reverse function is required: The valve is open in a de-energized state.The following table displays the appropriate combinations.6 / 16Siemens Building TechnologiesElectrothermal actuators STA..3.., STP..3..CE1N4884en 03.05.2012Note Response at de- energized actuatorDe-energized actuatorTypeSTA..Valve Radiator valves VDN.., VEN.., VUN.. Closed VP..47.. VD1..CLC V..I46.. VPD.., VPE.. VPP46.., VPI46..,A ↔ AB open 1) Closed AB ↔ A closed ClosedSmall valvesZone valves Combi valvesSTP.. Open 1) A ↔ AB closed Open 1) AB ↔ A open 1) Open 1)1) Controller must support NO valve actuator combinations.