Thermal expansion valve exterior temperature (including electronic expansion valve) when it under normal circumstances, the lexpansion valve body is cold, and have dew water, refrigerant flow voice is boring. Under abnormal circumstances, the first is the valve body is relatively cold, the surface have many dew water, or even frost, the noise of refrigerant flow is large (gas flow). The reason is that the filter is blocked, or the coolant in the power box leaks and the valve hole can be closed.
If capillary temperature is normal, the capillary cool and dew condensation, have sound of liquid flow. Abnormal circumstances, the surface is cold and have dew, but the sound flow is louder, is the gas flow, the reason is lack of refrigerant; the second is the surface is not cool, no condensation, can not hear the sound of the flow, the reason is filter clogged or capillary blocked.
If evaporating temperature is nder normal circumstances, the evaporator surface is very cold, the dew water continue to drop, the temperature of the inlet and outlet air is high, usually Δt can be 12 ~ 14OC. In abnormal circumstances, the evaporator surface is not too cool , little dew, or no condensation, you can hear the sound of refrigerant flow is very loud, small difference between the inlet and outlet air temperature. The reason is the lack of refrigerant, or small expansion valve opening.