R508B

R508B is an azeotropic blend of non-ozone depleting HFC refrigerants (R23 and R116).  It has similar properties to R503 and is used for very low temperature applications, such as environmental test chambers and medical freezers. 

Although R508B is an azeotrope, we recommend it should always be removed from the cylinder as a liquid when charging the system.  R508B is not compatible with mineral oil, and equipment manufacturers recommend Polyol Ester (POE) oil - see our Lubricants section.

R508B can also be used to retrofit existing systems containing R503, however it will be necessary to change the oil to POE.

It has a GWP greater than 2500 and virgin product cannot be used for servicing in the UK and EU in stationary refrigeration applications > 40 CO2 T eq. There is an exemption for systems operating below -50 degrees C.