First, I would try replacing your filter of the high MERV type with a standard, cheap (throw away) type. See if that solves your problem. This you can do yourself. Sometimes, those filters are too restrictive and can decrease the airflow across your evaporator coil such that the thing ices up.

Second, (and you may want to consult a professional on this--definitely, absolutely cut the power to the unit first!) is to check your blower compartment and see if it is extremely dirty (or if the evaporator coil is extremely dirty). These factors can prevent adequate airflow across your evaporator coil thus increasing the likelihood that it ices up. Another good thing to check is to see if your OUTDOOR coil on your condensing unit is clean. If the thing is plugged with leaves, hair, dirt, dead grass, etc...this isn't good either.

Third, you want to have a professional check your refrigerant charge on your unit. If all other factors are eliminated, an icing coil typically means low refrigerant charge. If the refrigerant charge is correct, then the thing to do as a "try" would be to have the technician (or yourself if you are so qualified) to increase your blower speed. This will decrease the likelihood that your coil ices up.

Another possibility could be (unlikely) a stuck TXV valve or plugged metering orifice or a pinched lineset.

Please (by all means) consult a professional if you do not feel qualified or able to do these things. A service call is only 100 bucks to check it out.

setting your temp to 82 degrees while you were gone made you air work very little, so the humidity in the house went up and
when turn down to 72 with hi humidity in home there was too much water running down the coil which slows down air flow, and the filter being a little dirty slows air flow. So it can freeze up. might not be anything wrong. i would say try it out and see what it does. You can check your temp. drop across the coil to see if you are getting 14 to 20 degrees
later paulbm

The things NOVACARRIERDUDE mentioned are absolutely reasons that would cause a freeze up. By the same token, it is not uncommon for a unit to ice up for the reasons PAULBM points out. There's other factors that can figure in to icing up but I do agree with Paul, to let things ride and see what happens now that you have it defrosted. I've seen units ice up like that when the house is 80 degrees and very humid and the night time outside temp drops into the low 60's. As mentioned, the condensation on the A coil restricts air flow, the unit starts icing up.

Generally, the coil shouldn't ice up. If it does, it's usually restricted air flow or low refrigerant.

I don't like to use the denser filters, the restrict air flow too much. Switch back to a standard filter. If you can, check the leading side of the coil for dirt. The damp coil can collect a lot of dust and hair that will eventually restrict air.

Since it is otherwise cooling properly, I would guess air restriction rather than low charge.

I wish I'd known all these reasons that coils can ice up last Fri. when it happened to mine. The repair guy said I have leaks in both the heat pump coils and the air handler coils in the garage and that they can't be repaired, have to be replaced for $3000. As a woman alone, my husband died in 02 while this house was being built, I feel at the mercy of repair people. I don't know what to believe.

It's a freon system, so I'm replacing it with a puron system anyway, so in this instance it doesn't matter, but I think in the future I'll borrow my brother-in-law for times like that. My late husband didn't know about stuff either, but he'd always just say little and nod his head a lot and repair people seemed to think he did, so we didn't get screwed. Actually, I was the handyman and did the yard work, and he did dishes and laundry and was good at making money (oil) and other talents.