Danfoss AFPQ 2 PN 40 — a self-acting combined differential-pressure and flow controller. A single rolling-diaphragm actuator both holds the differential pressure across the controlled section constant and limits the maximum flow to a preset value, without external power. This return-mounted (AFPQ 2) variant senses across the consumer and throttles the matching globe valve body to maintain the set differential pressure while capping flow at the adjusted flow-restrictor setting. 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; differential-pressure setting 0.5–1.5 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 "AFPQ 2, PN 40, 0.5 bar - 1.5 bar, 160 cm²". OEM P/N 003G5712. Technical data quoted verbatim from store.danfoss.com (code 003G5712). 1.0345, zinc plated; diaphragm EPDM (Rolling, fibre enforced); Standard size: AFPQ 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.