AC Unit is Frozen

jrotunda85

Pardon my ignorance in this post, I'm not very familiar with HVAC and the correct terminology so I've tried to circle some things for clarity in the photos attached.

Two nights ago I noticed that our house had gotten noticeably warmer (we usually keep the thermostat somewhere around 69-70 degrees). I checked the thermostat to realize that the house's temperature was around 5 degrees warmer than the setting, so I went and checked the indoor unit. On quick check, I noticed that there was ice around copper tubes and an insulated pipe that runs into the front of the unit (I've circled where I noticed the ice in 1.jpg attached).

I turned off the unit and let it sit for a few hours then I took out all the filters (I have permanent hydrostatic - I think that's what they are called - filter system in place). When pulling those out, I looked up in the AC into a sloped vent and the entire thing was covered by a sheet of solid ice (see 2.jpg attached).

Perhaps it's worth noting that when running, it does blow air and the air isn't overtly cold but it's not warm either, it's somewhere in the middle temperature wise.

I'm sure I need to call out an HVAC tech to fix it but do you all have any ideas on what's causing the issue, if there are anyways to fix it without an tech call, and if I need a tech any ballpark on the cost to fix such an issue?

Thanks for the help!

Attached Images

  

ben's plumbing

filter's could be dirty....causing air flow problem......or low on freon. could have a leak... clog in system...need to have it checked...

tima2381

Low airflow caused by a dirty filter is about the only thing you could fix yourself.

The system could also have developed a leak and become low on refrigerant, and this most commonly happens to the evaporator coil, the "inside unit" where those pipes in your first picture disappear into. If it's a leak, a tech can replace refrigerant which is very expensive if R22 ($40-$50/lb, and it could need a couple), but it will just leak out again over time. Replacing an evaporator coil could be $500 or so for the labor, and perhaps another $500 for the coil if it isn't covered by warranty.

jrotunda85

Thank you both for the quick replies. When I did take out the filter it was quite dirty so I've cleaned that off and I still have the unit off to let the sheets of ice melt. Is it ok to run the fan on the unit (but not the AC) or could that cause more problems?

carmon

I agree its one of those things.... low air flow .. low on refrigerant.... possible metering device not feeding..... metering device i doubt..... most likely refrigerant issue..... melt ice and see if coil is clean....

carmon

turning the fan on will speed up the process....

jrotunda85

Given again my limited knowledge of HVAC - once the ice melts where would I find this mysterious coil?

beenthere

The coil is what the ice is frozen on/to. It will have aluminum fins.

jrotunda85

So that's the sloped duct think that is in my 2nd picture in the original post?

beenthere

Thats it.

jrotunda85

Perfect, thanks for the help!

jrotunda85

The filters were actually pretty dirty so last night I cleaned them up and let the unit itself sit overnight with the fan on to thaw the ice. This morning I checked the inside again and all the ice had melted and the coil itself looked to be in pretty good shape, I sprayed it with compressed air to free up anything lose just for good measure.

I replaced everything and I’m running the unit on an interim basis to see if the filter was what the problem was. At first test, the air is coming out nice and cold. I’m going to keep monitoring the unit for the next day or so to make sure ice isn’t building back up, if it does I’m going to call out a tech.

Is there anything else I should be looking for other than the ice building back up?