A/c Filter medium

[silverdou]

Hi Guys,
I live about 20 miles west of New Orleans. I am experiencing too many days with my Amana(circa 1985) unit not being able to cycle. Yesterday after repositining two ducts, I was able to cycle unit @ 79 F.
Outside temp ~97 w/90% humdity
I am trying to do all the homeowner stuff; insulation,correct duct work, repair to plentum, insulate the freon return line, and Correct Filters!!
On the issue of filters I am getting more confused as to which medium to use. The higher the "MERV" rating the more sacrifice to air flow. Where is the "happy medium"??
Pleated, non-pleated, fiberglass, allegin.
If I am correct AIRFOW is paramount in controlling temperature. If I use a filter that allows less air flow, do I have to increase the Reurn Vent to bring air flow back. Is there some calculation to get these two factors in line??
Verry confused,
Thanks,
Silverdou

[dash]

"better " filter usually = more restrictive and less air flow.

You need your system tested to determine the ESP(external static pressure0,then use that number with the mfrs. fan data to determine the actual,design or redesign air flow .


Larger return grille ,duct or even a larger filter size all reduce the resistance .

[danglerb]

Better the filtering, typically the lower the flow rate, but nothing messes up flow like the stuff that still gets around the filter getting stuck in the blower blades and evaporator coil. More surface area on a filter gives it more flow, so opting for as large of a filter surface area is a good idea. What you need might be a "tune up" where a tech comes out and checks and cleans the system, tops up the freon etc.

[silverdou]

Got home @ 3:30pm to find a/crunning and temp on thermostat to be 80 F
It is noe 8:10pm and temp is still 80 F
Temp out of register is 73 F
Yesterday @ 09:30am temp out of register was 58 F I am soooo confused
Amana 4 ton ~1985 model
Technician came by 1 week ago added 1# freon. Unit will not catch up untill ~9:00pm and cycles untill ~10:00am.
Any help would be greatly appriciated
Thanks,
silverdou

[fl1]

Check the filter,could be dirty.Coils and blower could need cleaning,could be duct leaks.


Call a Pro for what you can't check yourself.