Danfoss AFQ 2 PN 40 — a self-acting flow limiter (flow controller). It holds the flow through the controlled section at a constant maximum, independent of differential-pressure variation, by throttling the matching globe valve body via its rolling-diaphragm actuator. The actuator carries the diaphragm and setting spring only; it combines with a Danfoss VFG 2 / VFGS 2 / VFU 2 globe valve body (ordered separately) to form a complete self-acting controller for district heating and district cooling circuits. Actuator diaphragm area 160 cm²; setting 0.5 bar; suits valve bodies DN 65–125. Media temperature 2 °C to 150 °C; maximum operating pressure 40 bar. Actuator housing Steel, mat. 1.0345, zinc plated; diaphragm EPDM (Rolling, fibre enforced). Medium: district heating/cooling circulation water (glycolic water up to 30%). OEM designation "AFQ 2, PN 40, 0.5 bar, 160 cm²". OEM P/N 003G5603. Technical data quoted verbatim from store.danfoss.com (code 003G5603). 1.0345, zinc plated; diaphragm EPDM (Rolling, fibre enforced); Standard size: AFQ 2; Pressure rating: PN 40; Temperature range: 2 °C to 150 °C; HS code: 8481.90. Used in commercial refrigeration, provision-room cooling and reefer plant rooms across HFC, HFO and CO2 (R744) refrigerants. No.