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Discussion Starter · #1 ·
Came home today and there was no air flowing from the vents and noticed the main freon line was frozen. The filter was dirty i changed it and just last week i had unclogged the main ac drain line which usually holds some water but today it was dry as hell. Its been in the 100s this month. What is the problem when this happens? The indoor unit fan is blowing just something is frozen and not allowing air to flow out the vents.

What is the usual reason for this issue? Its frozen and i guess froze the condenser or cold air evaporator core duct part of the inside ac unit as well as its not allowing any air to blow through? I changed the filter wasnt too dirty but dirty and was working just yesterday.
 

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Low airflow or refrigeration problem.

Turn it off so it can defrost, check for plugged filter and blocked vents, try again - if problem persists, call someone out.
 

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Discussion Starter · #3 ·
Ok maybe it was the low drain line was clogged two weeks ago so i had unclogged it with 10ft of wire. Yesterday it had a puddle which is usually holds today it was bone dry when i came back and noticed no air flow from vents and seen it was frozen. The filter was pretty dirty maybe 3-4 months old. Let me get a picture i dont think it was too bad.
 

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Discussion Starter · #4 ·
The filter was 3-4 months old it runs alot during the summer. It wasnt blowing any air so im assuming the thing froze solid as i had changed the filter and it didnt help any. I buy the 3 packs of 3M filters for 11$ from lowes.
 

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When I had that happen due to low air flow I put the thermostat on fan only and let it run blowing room temp air against the coil.
 
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Discussion Starter · #8 ·
Ok great its blowing cold air on fan only finally starting to thaw. I think itll be fine to run unfiltered until its defrosted? With a filter in will it that and drip down into the filter area destroying the 4$ filter or is the frozen part just above the drip rail pan that allows the water to drain outside? Regular goodman hvac unit.
 

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Ok great its blowing cold air on fan only finally starting to thaw. I think itll be fine to run unfiltered until its defrosted? With a filter in will it that and drip down into the filter area destroying the 4$ filter or is the frozen part just above the drip rail pan that allows the water to drain outside? Regular goodman hvac unit.
Yeah, that's fine. Just keep it changed regularly once it's up and running.
 

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I put a reminder in my phone to check it once a month.
 

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Discussion Starter · #11 ·
Is it supposed to be changed monthly or every couple months? for some reason i thought it was 3-4 months but now i dont see it labeled anywhere on the filter.
 

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I usually end up changing mine every 6 to 8 weeks. Depends on the air in your part of the world.
 

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The filter was 3-4 months old it runs alot during the summer. It wasnt blowing any air so im assuming the thing froze solid as i had changed the filter and it didnt help any. I buy the 3 packs of 3M filters for 11$ from lowes.
If you want to use pleated style filters, get the lowest grade - "basic protection", "dust and pollen", for 3m no more than fpr 600, for others no higher than merv 8 and merv 6 is preferred.

The denser filters plug up and get very restrictive to airflow fast - they may start about the same as the lower grade filters in that respect.

If your a/c is 3 ton or more and that's your only filter, do not use pleated filters at all, go fiberglass or hogs hair (blue) washable. Bigger units need more airflow and the filter needs to be sized larger when using pleated.
The outdoor unit model number will have digits indicating the size of - 18=1.5, 24=2, 30=2.5, 36=3, etc.

If you want to use a pleated filter and your system is 3 tons or greater, have a contractor install a larger filter holder/return grill.
 
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Discussion Starter · #17 ·
What filters do you suggest? I hate the real expensive filters theres the real cheap green cross threaded filters and these 3m filters which look like theyre good thick filters? Its working normal as it should it defrosted overnight its 107 degrees here in summer texas and yes i replaced it 3 months ago i shouldve checked it 6-8 weeks.
 

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Discussion Starter · #18 ·
What filter are you suggesting is best i dont want any contaminations up in the main ac core that could clog and cause expensive issues. These 3m filters seem like nice healthy filters to catch most debris. Are you referring to the green cross threaded filters that are real cheap? Have any pictures of the filters you are suggesting. They are 1"x16"x25" slide in filters.

What does merv 8 merv 11 merv 13 mean on the filters? These 3m filters seem of good quality compared to the old classic green crossthread filters they sell or used in the 90s i think walmart stocks them in singles.
 

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Discussion Starter · #19 · (Edited)
Yes i use these basic pleated 3 pack which is a merv 5 rating so they shouldnt be too restrictive while catching most dust and preventing dirt from entering the ac system. They use to use the green cross threaded style line filter on the same unit in the 90s my grandparents before these 3m came out.

Heres what im using suggest changing filter every 3 months. Filtrete 16-in W x 25-in L x 1-in Basic Pleated 3-Pack Pleated Air Filter in the Air Filters department at Lowes.com

Basic has a merv rating of 5 what does merv mean? Is that airflow thru the filter or dust collection?
I see merv 5 should be a better flowing filter then a higher rating merv filter and not be as restrictive?
  • Outperforms fiberglass air filters for your furnace, air conditioner or HVAC system
  • Change filter at least every 90 days For optimal performance of your heating and cooling system or HVAC system
  • For residential use only
 

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Hopefully this will be OK when it thaws out. But I have never seen a filter get anywhere near that dirty in 3 months. What on earth is getting in the air? I use similar ~Merv 8 pleated filters and they go 3 months looking hardly used. And yes, it is hot, been mid 90s and humid since I can recall. Until today anyway. You need to change those far more often, probably monthly. Maybe also invest in an air cleaner.
 
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