Is a block of ice in an air conditioning unit 'normal'?

We have an air conditioning unit in the apartment we moved into earlier this month that has in the past just randomly stopped working. The maintenance man came out and by his own admission did nothing to it but it magically worked again.

We moved on.

Today, the same thing happened. The ac just quit. Air was barely blowing out, and it wasn’t cool air. It was about the same as a fan with a few missing blades.

Out of frustration we popped off the panel to the unit and saw a block of ice sitting on the filter three inches thick, covering the entire filter and with ice going through to the other side of the filter as well. The pipes leading up towards the ceiling also have ice around them. And don’t even get me started on the 30 Day Filter inside that hasn’t been touched in what looks like a year – there’s a half inch thick coat of dust and grime. It’s gross.

We know nothing about air conditioning units. We assume this isn’t normal but we wanted to check on any specific issues that might cause this kind of build up of ice. We’re leaving the panel off the wall for the time being as it’s blowing air through the house – a small comfort. Can anyone tell us the issue? Is there one?

Besides the filter – obviously. :)

We run the ac at 65 usually, and never seen this in a unit before.

For reference it seems to be a First Co. unit – a 614H?

Should we not run it at all until more maintenance comes out? Do you have any advice for dealing with the rental office?