Danfoss ASV-PV 3G DN 50 — third-generation self-acting differential-pressure controller for automatic hydronic balancing. Installed in the return pipe of a heating or cooling circuit, it holds a constant differential pressure across the branch or terminal (paired with an ASV-BD/ASV-M/ASV-I partner valve and an impulse tube), so that two-way control-valve authority stays high and flow noise is avoided at part load. Differential-pressure setting range 20-40 kPa (factory setting 30 KPa), Kvs 20 m³/h, Grey cast iron (EN-GJL-250) body, External Thread connection, PN 16, media temperature -10 °C to 120 °C, integral shut-off. OEM P/N 003Z0621. EAN 5702421558416. Technical data quoted verbatim from store.danfoss.com (code 003Z0621).