Evacuation and Charging of Cooling Systems

Refrigerators, air conditioners and cooling machines operate according to a thermodynamic cycle process, in which heat is transferred from the cooling cabinet to a warmer surrounding.


As transport medium for the heat a refrigerant is used inside the closed cycle cooling system. Before this cooling system is filled or when it is to be refilled after maintenance work it first has to be completely evacuated to approx. 10-3 mbar, so that no rest of air or air humidity remains in the system. This would reduce the capability of the appliance and may even lead to serious damage of the cooling system. Further care must be taken thet there are no leaks in the system. Therefore the vacuum level which is reached after evacuation has to be checked accurately


Compact vacuum meters of type VD84/2 with external Pirani sensor measure the vacuum inside the cooling system with appropriate accuracy and resolution. The handy gauges are easy to operate and are optimal for use in the service and maintenance. Via an USB interface the measurements can be stored and analyzed on a PC.

Main points in brief

  • Integrated data logger
  • USB interface
  • External Pirani sensor