Overcharging of Refrigerant

The cause is that the air hitting the cooling coil is too moist for too long.

You have to replace the "capilar" filter installed between the hi and the low pressure lines; then perform a full vaccum to eliminate humidity and air; then fill with gas to specs; then sit and leisurely enjoy the marvels of modern climate control.

Yahlasit

Sorry, I overlooked the part where you say "refrigerator".

In that case, have a cold beer.

Yahlasit

My understanding is that you weighed in the refrigerant charge as per the manufacturer, and now have a icing problem on the suction line?

That said I need to know what you are working on and the application. The type of refrigerant used, operating pressures and the suction line superheat.

It could be an over charge or a refrigerant metering device failure or several other problems.

Get back to me with the information.

I suspect that moisture in the system. Corrective actions are Purge,evacuate system,install new drier,recharge the system.

What type of compressor your refrigerator have? What is the size? What kind of lubricating oil system you have? These informations needed for correct feedback. However I try to guess some thing like following:

1. Generally lub. oil get mixed with refrigerant while in operation. Some quantity of mixing is desirable. But when more oil get mixed, it will result rise in refrigerant level in evaporator. It may be percieved as overcharging of refrigerant. This may cause entry of some liquid refrigerant in compressor suction line bringing extra cooling. This can be identified by considerable drop in discharge line temperature and overloading of compressor. This is detrimental for compressor. If it is so, temporary solution is to remove some refrigerant and run the machine at lower load. Next, to remove exess oil from evaporator by transfering refrigerant to condenser.

2. Your refrigeration load may be low. Put some more load.

Good Post Coldspot, the only thing I can add is to make sure it is completely defrosting on the off cycle. If it's a frost free, then make sure the evap. is clear after the end of the defrost period.

Over charging will not cause icing on the suction side but inadequate flow of refrigerant will. One of the more likely causes of that is a plugged liquid line filter/drier and/or a plugged expansion valve filter. I'm assuming that both are properly sized as well as the liquid line. A sinlge step compressor that is too large for the evaporator coil will also cause the same problem. Check them out.

If this is a domestic/ house hold refrigerator there is one thing that you can check. On almost all of them they solder the capillary feed tube to the suction line. This acts like a heat exchanger that sub cools the liquid refrigerant, prevents flash gas and improves efficiency.

The solder tends to break down with age and the two of them no longer make contact. Frosting on the suction line will occur. If this is so, than clean both lines and bind them together with a double layer of electrical tape.