Air Conditioning - Cooling line on the outside unit is freezing-up

Last week my central air stopped working. The technician detected a leak on the outside unit which he repaired by replacing a valve and then he re-charged the system. I am noticing ice build-up on the cooling line on outside unit. The ice build-up is also visible on the compressor. The A/C seems to be running OK (its cooling). Is this normal? a friend told me its not and not to run the unit until this is fixed. The technician is not available for another week as it is pretty hot here (in Washington DC area). Please advise.

Thanks

Only two things will cause your problem & they are: (1) Low on refrigerant or (2) Not enough air flow across the evaporator (indoor) coil.

The second, you can do something about by making sure all registers are open & not blocked, making sure the air filter is clean, making sure the blower wheel is clean.

The first requires a certified tech. When a system is in need of refrigerant, unless the tech is sure he/she has found & fixed the leak, some method of leak searching should be done. My personal preference is to inject a dye & come back at some future date with a UV light to search for the leak which will leave a stain visible under UV. Here is a link to some information about it:
http://www.spectroline.com/hvacr/hvac_howitworks.html

Ice on the suction line or evaporator coil is not normal. Shut it down and get a tech. Trying to run it another week may end up damaging the compressor.