Danfoss RAS-C 5040 — self-acting thermostatic radiator sensor (control head), OEM order code 013G5040. The RAS-C 5040 is a self-acting thermostatic operator (control head) for Danfoss radiator valve bodies. It modulates the valve in proportion to room air temperature to hold the set room temperature without any external power or wiring; the liquid charge gives stable, hysteresis-controlled operation and the sensing element is built into the setpoint dial, sensing the air immediately around the valve. Setpoint range 8 °C - 28 °C. Features: frost-protection setting, positive shut-off (closes the valve at the low end of the scale). Valve connection RA. Colour Black RAL 9005 / White RAL 9016. Housing plastic. Genuine Danfoss part; specification quoted verbatim from store.danfoss.com (code 013G5040). OEM P/N 013G5040, EAN 5702420020785. HS 9032.10.