Check valves CV / CV..HD PLUS series

The check valves are classified as “Pressure accessories” in the sense of the PED Directive 2014/68/EU, Article 2, paragraph 5 and are subject to Article 4, paragraph 1, letter (c), of the same Directive.

All the products range is suitable for use with fluids proper to the Group 1 and 2, as defined in Article 13, paragraph 1, letter (a) and letter (b), of PED Directive 2014/68/EU with reference to Regulation (EC) n.1272/2008, in accordance with safety classification A1, A2L and A3 in Annex E of standard EN 378-1:2016. Examples of A1 and A2L refrigerant fluids are:

– HFC R32, R134a, R404A, R407C, R410A, R507;

– HFO R1234yf, R1234ze and blends HFC/HFO R448A, R449A, R450A, R452A, R452B, R445A, R454B, R454C, R513A.

Examples of A3 refrigerant fluids are (HC hydrocarbon):

– R290, R600, R600a, R1270;

The function of the check valves is to ensure the unidirectional passage of the fluid through the pipes.


  • CONSTRUCTION SERIES CV1 & CV3: The body and the nipple are made from brass bar UNI EN12164 – CW614N and the solder connections are made of copper tube EN 12735-1 – Cu-DHP. The clapper seat is made of modified PTFE and combines robustness with excellent resistance to high temperatures; the spring that keeps the gate shut is made of austenitic stainless steel AISI 302. The seal between body and nipple is ensured by a HNBR O-Ring.
  • CONSTRUCTION SERIES CV2 & CV4: The differences with the previous ones are the body and flange made of hot forged brass EN12420 – CW617N and the seal between body and flange, which is made, in some models, in an asbestos-free aramid fiber DIN – DVGW approved in accordance with DIN 3535, part 6 FA, in other models it’s in HNBR.
  • CONSTRUCTION SERIES CV..HD: The HD series differs from the standard series for the spring used which has a greater rigidity which increases the Minimum Opening Pressure Differential: this makes the operation of the valve less sensitive to the fluctuation of the transient flow rates during the start-up and shut-down of the compressor, avoiding the ignition of noisy resonances of the flow. This feature makes the HD series valves particularly suitable for installation near the compressor and in systems with inverter-driven compressors.


While installing the valve, make sure the arrow direction matches the direction of flow. We recommend installing the valves CV1 and CV3 Series with the vertical axis and the arrow pointing upwards; installations with the inclined or horizontal longitudinal axis are tolerable. The installation of the valves CV2 and CV4 series shall be done with the longitudinal axis lying in a horizontal plane and with the cover facing upward, furthermore only for this series is necessary to dismantle all the removable components from the valve and if the gasket does not remain on the cover, remove it manually from the body. The brazing of the valves with solder connections shall be done with a low melting point alloy. During this process do not point the flame directly towards the body and allow the latter to cool by natural convection in the air.