... The introduction of volume control damper,air damper,volume damper NameModelFunction codeFunctionsspecificationShapeDiacharge fume valvePYF-1SDDC24V turned on,manual open,hand reset,out ... fume valvePYF-4BSDDC24V turned on,long distanced manual open,hand reset,out put opening signal≥320* ... outputs DC24V electrical signal opening,long distanced manual open and hand reset.≥250*250rectangle The performance ...