Dry evaporator coil using automatic expansion valve (AEV) or thermostatic expansion valve (TRV) refrigerant management. These evaporators must be clean both inside and out for good heat transfer. They must contain the right amount of liquid refrigerant in the proper vapour pressure to ensure sufficient cooling. Air or water cooled must flow in and out of evaporators effectively, evaporator must be sealed and the appropriate size.
You should check these terms. Ideally, the pressure at the inlet of the evaporator (immediately after AEV or TEV) should be measured. Pressure should also be measured at the output. However, most technicians to test only on the low side pressure at the compressor suction service valve. They believe that the pressure in the evaporator is close to this pressure. Pressure drop due to friction in the pipes and bends can be tested. This is done by reading the low pressure side of the unit. Then read again, and stop the compressor. Lifting pressure-pressure drop. As a rule, it is a loss of pressure would be 2 3 psi psi.
Evaporator temperature should be checked.
Thermometers can be mounted on tubes with a spring-loaded clip on the thermometer owners. Superheat setting the thermostatic expansion valve can be checked using thermometers. The optimal choice is when the bulb air temperature varies as the device works. The location of the liquid in the evaporator can also be determined that way. Frost accumulation acts as insulation and also tends to reduce consumption of air. Accumulation near TEV usually means too big superheat adjustment together with low suction pressure. Spotted frost usually means uneven air flow through the evaporator. Otherwise, this may mean that some thawing elements are not working.
Air flow through the evaporator can be checked with the anemometer. This is also known as air velocity meter. If the air outlet or inlet too small, the evaporator will be sorely lacking. Air temperature at the inlet and outlet can also be checked. Temperatures normally drop to approximately 15F (8C)as it passes through the evaporator. When checking for leaks, fan and your device must be turned off. On the low side pressure shall be not less than 15 kPa 30 psi or 207 kPa) when testing for tightness...
Industrial