Danfoss AVP-F (003H6231) — self-acting differential pressure controller with a fixed, factory-preset setpoint, PN 16, DN 15, for district heating and central heating systems. The AVP-F holds a stable differential pressure across the controlled circuit so that connected control valves keep their authority; unlike the adjustable AVP it has a fixed (non-adjustable) setting of 0.5 bar and no adjustment handle, giving a tamper-proof, permanently set Δp. Unlike the AVPB it is a differential-pressure controller only (no integrated flow limiter). It consists of a control valve and an actuator with one control diaphragm. kVS 2.5 m³/h; fixed differential-pressure setting 0.5 bar. Maximum differential pressure 12 bar; medium temperature 2–150 °C; leakage 0.02% of kVS (IEC 534). Valve body red bronze CuSn5ZnPb (Rg 5), valve seat stainless steel 1.4571, valve cone dezincing-free brass CuZn36Pb2As, control diaphragm EPDM. Connection external thread G ¾ A (ISO 228/1) via tailpieces (ordered separately). Media: circulation water / glycolic water up to 30% (pH 7–10). OEM P/N 003H6231. Technical data quoted verbatim from the Danfoss AVP / AVP-F (PN 16) data sheet and store.danfoss.com (code 003H6231). differential pressure 12 bar); Temperature range: 2 – 150 °C (medium); HS code: 8481.80. Used in commercial refrigeration, provision-room cooling and reefer plant rooms across HFC, HFO and CO2 (R744) refrigerants.