Properly install a temperature sensor on the suction pipe 10 cm from the condenser unit. Turn on the equipment and wait for the temperature of the air-conditioned room to stabilize; Read the suction pressure in the manifold (PSUC). Read the temperature indicated by the sensor (T). Using a pressure and temperature table for R22 or the type of refrigerant indicated on the equipment, obtain the saturation temperature (T). SATURATION SUCTION.
Calculate the degree of overheating (SA) using the equation below: In the evaporator, the fluid steals heat from the environment and evaporates. For this process it needs a certain amount of heat. Overheating of the fluid is the heat it gains beyond what is necessary for complete evaporation. Therefore, overheating can be understood as the difference in the temperature of the fluid at the compressor inlet in relation to the temperature of the fluid that vaporizes in the evaporator.
If the superheat is too high, there are problems with the compressor oil viscosity. If the superheat is too low, there is a danger of fluid entering the liquid form in the compressor.
SA = T - T SUCTION SATURATION
The ideal overheating range is 5 ° C to 7 ° C and the acceptable range is 4 ° C to 9 ° C. If SA is less than 5 °, remove refrigerant from the refrigeration line. If SA is greater than 7 °, add refrigerant to the refrigerant line.
Example: The suction temperature is 8ºC and the pressure is.
In the saturation table for R-22 we find that for 59 PSI, the saturation temperature T = 59 PSI SATURATION 0.4 ° C
SUP = 8.0 - 0.4 = 7.6 ° C. . The calculated value found is outside the ideal range, but is within the acceptable range, so there is no need to add or remove refrigerant.
