(1) Before adjusting the thermostatic expansion valve, it must be confirmed that the abnormality of the thermostatic expansion valve is caused by the deviation of the thermostatic expansion valve from the optimum operating point, not caused by other factors such as low Freon, dry filter blockage, filter, fan, belt, etc. of. At the same time, we must ensure the correctness of the temperature package sampling signal, the temperature sensing installation location must be correct, absolutely can not be installed directly below the pipe to prevent the bottom of the tube oil and other factors affect the temperature sensing package the correct temperature.
(2) Thermal expansion valve adjustment precautions Thermal expansion valve adjustment work must be carried out in the normal operation of the refrigeration unit. As the evaporator surface can not be placed thermometer, you can use the compressor suction pressure as the saturated pressure within the evaporator, look-up table to get the approximate evaporation temperature. With a thermometer to measure the temperature of the return pipe, compared with the evaporation temperature to check the superheat. Adjustment, if you feel too hot, you can turn the adjustment screw clockwise (ie, increase the spring force to reduce the thermal expansion valve opening), so that the flow decreases. Conversely, if you feel too hot, that is, lack of fluid, you can turn the adjustment screw in the opposite direction (counterclockwise), so that traffic increases. Due to the actual work of thermal expansion valve temperature sensing system there is a certain degree of thermal inertia, the formation of signal lag, the basic stability of the operation before the next adjustment. Therefore, the entire adjustment process must be patient and meticulous, adjusting the number of turns of the screw should not be too fast too fast.
(3) Thermal expansion valve specific adjustment steps:
1) downtime. Insert the probe of the digital thermometer into the insulation at the return air inlet of the evaporator (corresponding to the temperature sensing package). Connect the pressure gauge to the tee of the compressor low pressure valve.
2) Turn on the compressor, let the compressor run for more than 15 minutes, enter the steady running state, make the pressure indication and the temperature display reach the stable value.
3) read out the temperature of the digital thermometer temperature T1 and pressure gauge corresponding to the temperature T2, superheat the difference between the two readings T1-T2.
