Specifications

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6720649497 SM HP270-1 2012/09 en
Pict.66 – Expansion valve and bulb position
Sub-cooling
The sub cooling is the difference between the condensing temperature and the liquid line temperature. The
condensing temperature is determined with a pressure gauge and the liquid line temperature is measured with a
digital thermometer
 Takes place in the condenser and indicates the liquid refrigerant cooling after it has changed into liquid
state. The sub cooling is created by adding so much refrigerant into the circuit that a level of refrigerant is
present in the bottom of the condenser.
 The higher level the higher the sub cooling becomes. Theoretically we can sub cool the liquid down to the
temperature level of the incoming heat carrier. In practice this is not possible, when the level reaches a
certain level, the condensing pressure rises.
Adjusting the sub cooling:
First make sure that the superheat is properly adjusted
The adjustment of the sub cooling is made by filling or extracting refrigerant.
Adding refrigerant = the sub cooling increases (the level of refrigerant in the condenser is higher and the liquid
is then more sub cooled by the inlet heat carrier.)
Extracting refrigerant = the sub cooling decreases (the level of refrigerant in the condenser is lower and the
liquid will then be less sub cooled).