M0G140F7-01 06/11/07 pag 31
REFRIGERANT TABLES
THIS SECTION IS DEVOTED ONLY TO QUALIFIED TECHNICIANS THAT KNOW THE FOLLOWING:
• THE OPERATIONAL PRINCIPLES OF THE REFRIGERATING CIRCUIT OPERATION
• THE MODES OF DETECTING TEMPERATURE AND PRESSURE
• THE RISKS RELEVANT TO THESE OPERATIONS
The data of the tables allow the testing of the refrigerating
circuit operation by the detection of a few objective
parameters.
The data are significant if they are detected
simultaneously and while the refrigerating circuit is
running.
• Liquid temperature
• Return pressure
• Return temperature
• Condensing pressure
The following examples are indicatives , the values considerably change according to the type of unit and the working
conditions.
OVERHEATING = return temperature – Saturation temperature
Return pressure 7.2 bar
Return temperature 7.3 °C
overheating 7.3 – 0.8 = 6.5 °C
SUBCOOLING = condensing temperature (pressure *) – liquid temperature
Condensing pressure 29.6 bar
Liquid temp. 45 °C
subcooling 49.91 – 45 = 4.91 °C
* It is important that the condensation pressure is detected as close as possible to the point where the liquid temperature is
detected, in the event that the calculation will be effected by the losses of charge (and, therefore, of temperature) caused by
the refrigerating circuit components placed between the two measurement points.
For R410A the glide was not considered, since it is close to 0.
The values in the tables refer to a specific refrigerant supplier; slight differences are possible with other suppliers.
Pg = P gauge = relevant pressure (read on the pressure
gauge)
Ts : saturation pressure
Td = dew point temperature
Tb = bubble point temperature
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