I have a newly installed, (maybe four months ago), central AC unit. It is a split system, 3.5 tons, Rheem 13 SEER. Both the compressor and the air handler were replaced.
All was working fine until yesterday, when I began hearing a dripping sound coming from beneath the air handler. A quick look and I see the coils are packed with ice, and as the ice melts the water gathers.
Can I assume correctly that somehow, somewhere, the refrigerant is leaking? Can I also assume this is highly irregular in a four month old unit? I've got the tech who installed the unit coming by on Wednesday morning. What is the fix? Replacement of the coil, repair, etc?
And can I run the unit in the meantime? South Florida is mighty hot without it :(
Thank you!

Yes, the #1 cause of ice on the coils is a loss of freon... but it's possible also that they are just dirty... and now allowing good air flow.

1. Shut the system down and let the ice thaw.
2. Clean the coils well with coil cleaner.
3. Turn the system back on and cross your fingers.

If it freezes back up you're probably low on freon. Have the hvac guy put a gauge on it to see if it drops and if so how fast. From that measurement he can probably give you a reasonable estimate of how long it will last if he fills it up.

If it drops slow or not noticeably at all, he can refil it and it will last you anywhere from months to years.

If it drops fast, then he'll need to make repairs before refilling the system.

Rick, is it possible the coils are that dirty after only four months of use?
Same question with freon use: can/should the system be low already?

I'm sorry. My bad. I gave you the "rote" answer for coils freezing up. I scanned the post for keywords then my fingers took over - moving faster than my brain :o

I'd have to think, then, that there is a leak in the system - either in lines somewhere between the new units (presuming that they did not also replace all the lines) or in a connection that the installer did not do quite right.

I would definitely get the installer back out there to check it out.

Hehe.. . fingers moving faster than the brain. Be careful! That's how I ended up married, with two kids.
Ahem.. . anyway, I have the installer coming out tomorrow. I'm sure, as you said, there is a leak somewhere in the system. Hopefully, he'll run his test, find it, fix it, and problem solved.
In the meantime, is there any harm in running the unit?

No "harm" to the system, but make sure that you keep it off long enough for the ice to melt. If it's frozen when he gets there, he may not be able to do what he needs to do. I don't know the technicalities of it, but on our apartments, tenants sometimes ignore this warning and the hvac guy gets there, finds it frozen, and says he'll have to come back when it's not frozen.

I'm not sure I'd run it long frozen up - #1 - it won't cool properly and you'll be stressed trying to keep an eye on it until it's fixed - #2 - it will run your compressor continuously trying to reach what's set on the T-stat - # 3 - low freon running continuously may damage your compressor. With a recent install - more likely think freon leak if it were running okay previously. Low air flow (dirty filters, blocked ducts, faulty blower) can also lead to icing up... Get the installer out there pronto...

PS - Give us a follow-up... Thanks...

The tech is coming by tomorrow. In the meantime, I have been keeping a close eye on the situation. But, something odd occurred today. There has been no ice forming on the coils, and no water dripping today. The unit is performing perfectly fine and giving no indication of anything being wrong. This is perplexing. Why would there be a block of ice on the coils one day, and nothing the next. Weather conditions are the same, and the thermostat setting never changes. We keep it set at 78 degrees at all times.

I had a very similar experience recently and it turned out to be an intermittently slow blower motor. If you have time left to do it, listen to the motor while it is running OK - then listen to it when it ices up. Note any difference in speed or blower output. I eventually changed out the blower motor and it has performed beautifully ever since.