HVAC Guys please!!

[JZ67]

Woke up around 4 am cuz my bladder must be shrinking with age. I'm sure no one here can relate.

I notice that there is no air coming out of my vents but hear the unit running. House feels cool but I have a ceiling fan moving air. I go check out the thermostat and it is flashing 'replace battery' but reading at 24.5 degrees. The thermostat is set for 23.5. I replace the battery and the thermostat read 26.

I go to the furnace and pull the filter that I meant to change about a month ago and it is solid black. It was last replaced around April as I was finishing my basement and changing it every month. But, yeah solid black. I had to peal it back t make sure it started off white - it was so uniformly black. I replaced the filter.

Kids have been burning candles a lot lately...they think their dad doesn't know what weed smells like I guess. Smells a bit worse being masked by a scented candle. I hate those fucking obnoxious candles!

I open a panel and see the coil is frozen so I shut off the AC and turned the fan on. At 7 am, the coil is thawed out so I switched on the AC and it's blowing cold as normal. I should mention everything seemed to be running normally up until last night.

What should I be looking for now?

[ZR]

Rookie HVAC wanna be opinion.

If air was restricted enough because of the filter, yes it could freeze. Once A coil was clear of ice, did you confirm tray is draining properly? Also good idea to make sure inside of the A coil itself is not plugged / restricted.
Another often overlooked bit of maint, do you check airflow through the coils on outside unit at least once a year? Very easy for them to get plugged / restricted from dirt n debris.

[JZ67]

Rookie HVAC wanna be opinion.

If air was restricted enough because of the filter, yes it could freeze. Once A coil was clear of ice, did you confirm tray is draining properly? Also good idea to make sure inside of the A coil itself is not plugged / restricted.
Another often overlooked bit of maint, do you check airflow through the coils on outside unit at least once a year? Very easy for them to get plugged / restricted from dirt n debris.

I can't access the coil inside the unit to see if it is restricted or not. I clear off the outside unit every time I cut the grass with a leaf blower. It's clear.

[True Blue]

Possibly your system is low on refrigerant, frozen coil is one of the symptoms. Need an HVAC tech to check the levels. Hopefully Screw (John) will see this thread and be able to help you out.

[USAWIT2]

If the filter was that dirty the lack of air flow will freeze up the A-coil.
If it freezes up again after unthawing and changing the filter the unit is likely low on refrigerant.

[Das 5.0]

Just had this happen to me on Canada Day. All frozen up - thawed it out , replaced filter (wasn’t that bad) and hosed down unit outside. It’s been working mint since but still getting someone to have a look - if yours doesn’t fire back up it may be low on Freon. Also what ZR mentioned. The coil I could get to as it’s just had a few screws and tape - used a heat gun to thaw out the coil in the furnace. House went from 80 to 71 within 12 hours.... ahhh thank god....

[ZR]

On mine, guess previous owner either ran without a filter or let it go too long, inside / center of the A coil had a thick coating of debris n dust. While a bitch to access, only took a few minutes to gently vac clean. Well worth the effort in my case.

[JZ67]

12 hour update...the unit is blowing cold air and the coil is clear. I'm keeping and eye on it and my fingers crossed.

[Screw]

You should be ok
April filter & a Reno + usage this summer ya it would freeze

[redo75]

Shut ac unit down and look inside of furance . At the bottom of coil could have build up of dust. Vacuum coil GENTLY. Flush with water to wash off rest of dirt on inside of coil.