short of it it seems that filters or causin' flow restriction in 'bout 10 ta 15 days?.. this unit is 'bout ten yrs. old.. return airways are still jus fine as for as clean.. i've been really religious with changin' filter for years.. no construction of any kind inside house.. absolutely nothin' has changed in routine in household and/or maintance? this seems ta be a "sudden" change but at a loss as ta WHY.. this all started with a leaking coil change in inside unit.. it was found and replaced when it quite coolin' 'bout 15 days ago.. had ta get 'em back out here yesterday because of "not coolin'.. changed filter and everything went back ta normal??? tha ONLY thing i've changed is went from MERV 8 ta MERV 11 on last order last year.. would that subtle of a change bring this on???
thanks............ T

It may be to restrictive on that older unit. Try going back to an 8 and see if that fixes your issue.

Try going back to the MERV 8 and see what it does. After that the only thing I can think of is maybe they didn’t get the right tonnage coil and after the new filter gets dirty it is effecting the cooling.

Wonder if they changed fan motor speed when repairs were made. It’s just a changing the position of the wires to increase or decrease.

put an 8 in it ta try.. right now thats tha only thing we've changed in last two years.. will know ina 'bout 15 days!... new stuff was replaced by trane under warranty so doubt anything there.. multi speed fan that starts kinda slow and builds up velocity... hasn't changed that we can tell until filter gets a little dusty evidently............. jus weird?

That is weird.

What kind of filter are you using? I had a HVAC dude tell me that a lot of people go to these filters that claim to filter out more allergens and they are too restrictive. He recommended the plain ole fiberglass ones. Now if you live on a gravel road you may need a better filter.

same brand i've used for almost 10 years when this system was installed... only change was merv rating from 8 to 11 last year.. all pavement..

So what kind of filter life were you getting from the Merv 11 you had switched to last year before the new coil change 15 days ago?

tried ta remember once a month no mater what it looked like.. coupla times maybe 45 days tops.......... never a problem till now..

Cant get as much air maybe. anyway to see if your coil is freezing up? those fiberglass filters are cheap and better than being hot

You positive the a coil is clean?

tha air deal seems ta be tha problem but that shouldn't change "overnight".. should have shown up when we went ta merv 11's a year ago.... If thats tha problem???

done May 7.....Completed Date: Completed Date: Technician: Technician: Elvis Gomez Payment Term: Payment Term: Due Upon Receipt D E S C R I P T I O N O F W O R KD E S C R I P T I O N O F W O R K Returned to replace evaporator coil. Pumped down refrigerant into condenser coils. Cut pvc and copper lines and removed leaking evaporator coil. Installed new evaporator coil. Reconnected pvc and copper lines and added new insulation and evaporator coil. Pressure tested system with 200 psi of dry nitrogen pressure. Pressure held no leaks. Ithen pulled system into a deep vacuum under 500 microns. I added 7 lbs of R410a refrigerant. Tested system in cooling cycle. System is now cooling properly. Refrigerant levels are in Good operating range137LP, 293HP, SC11, SH12 odt75. I added clean out to primary drain line and flushed drain. Condenser coils were dirty I washed them off with water pressure.

If the merv 11 filters were lasting 30-45 days before the old A-coil sprung a leak and got replaced 15 days ago with a brand new coil that now quits cooling after 15 days due to the same type filter getting too clogged then something else is wrong. I’m betting that new coil has more pressure drop to the air flow due to not being an equivalent replacement. Maybe they got the wrong coil installed by mistake? If it were me, i would ask them to double check what coil got put in. Should have been an exact replacement and should not have to downgrade the filter to keep it working.