What are the failures of the air conditioning refrigeration system (R410A)

What are the failures of the air conditioning refrigeration system (R410A)

1. Poor cooling effect

When it is assumed that the system is blocked by welding, first check whether the system pressure and current are normal. You can use a pressure gauge to measure the suction pressure. For R410A working fluid, if the pressure of the whole machine is about 0.9MPa (outer ring temperature is between 33~36℃) ), the current is close to the rated current, and it is basically determined that the filling volume is normal and there is no welding blockage in the system;

If the suction pressure and current are too low, first check whether the opening of the electronic expansion valve is normal. You can listen to the sound of the expansion valve opening or closing when shutting down or turning on. If there is a "click, click" action sound, the electronic The expansion valve is normal.

　　 You can also observe the pipe temperature after throttling by the electronic expansion valve. If the expansion valve is stuck and cannot be opened, there will be no cold feeling on the large and small pipes and evaporator fins, and the indoor air outlet temperature is close to normal temperature. If the number of steps of the expansion valve can only be opened a little, you can observe whether there is frost in the pipe section after throttling. If there is frost, it is related to the number of opening steps of the electronic expansion valve or insufficient filling volume.

　　Note: R410A: The inner windshield is the highest windshield, and the cooling suction pressure is 0.70-1.10MPa; the current value is within ±30% of the nameplate;

　　 R22: The inner windshield is the highest windshield, the cooling suction pressure is 0.45-0.65MPa; the current value is within ±30% of the nameplate's nominal value.

　　2, check whether the internal machine evaporator is blocked by welding

Turn on the cooling condition, pull out the temperature sensing bulb of the inner machine tube (to prevent anti-freezing protection), and take out the cross-flow fan blades of the inner fan. After the evaporator surface is full of frost, check whether the frosting of each pipeline is even and whether there is There is no frosting in the individual liquid distribution pipes. If the liquid distribution branch does not appear frost, the branch may be blocked by welding.

　　 Generally, the evaporator is blocked by welding, the cooling capacity is insufficient, the power, current, and pressure will drop, and the suction and exhaust temperature is also lower than normal.

If it is difficult to remove the cross-flow fan blades, the following methods can also be used to verify the frosting: open the windshield at the lowest level in dehumidification mode or cooling mode and block all the air inlets of the inner machine with tape or other materials, and check after the evaporator surface is frosted The method is the same as above.

　　 3. Check whether the condenser of the external unit is blocked by welding. Turn on the heating condition, run under the super windshield, remove the axial flow fan blades of the outer fan, and check whether there is frost on the surface of the condenser and each branch. It is similar to the check of the internal machine, as long as the surface of the branch is not Frost, this branch may be blocked by welding.