DV-ZT-F

Visually inspect stainless steel valve seats for signs of erosion, corrosion, pitting, or chemical attack. Check sealing surfaces under magnification (20x) for any visible damage, scratches, or grooves that could compromise the seal.

Examine weight-loaded or spring-loaded valve pallets for cracks, permanent deformation, wear patterns, or loss of sealing integrity. For diaphragm-type valves (UB-SF series), check for tears, holes, or loss of elasticity in the FEP diaphragm material.

For flame arrester-equipped models (VD-SV-EB, PV-EB, UB-SF series), inspect the FLAMEFILTER® element for deposits, corrosion, or particulate clogging. Pressure drop testing or visual inspection of element surfaces is required; recommend cleaning or replacement if >25% blockage detected.

For -F model variants (DZ/T-F, DZ/E-F, DZ/EA-F, DV/ZT-F) with spring loading, verify spring force using calibrated testing equipment. Springs should return to original height without permanent set. Check for corrosion, stress cracks, or fatigue damage on spring surfaces.

Verify automatic condensate drainage is functioning on all models. Inspect drain holes and pathways for ice blockage, mineral deposits, or organic fouling. Ensure drain tubes are clear and properly positioned; test drainage with small water injection at operating temperature.