Seal up weep hole? Also ? about return filters

[Border411]

Here is my new American Standard setup:
Outdoor Unit: 4A6H5024A1
Indoor Unit:4TEE3F31B1

So I went with all of your advice and just replaced the air filter of my new unit from a Filtrete 1250 filter to one of the Naturalaire MERV 8 that comes in the 3 pack from HD for like $8. When I replaced the filter, I started hearing the sucking of air coming from near the condensation drain fittings on my unit and found a weep hole between the 2 bottom-most drains fittings. I can hear a significant amount of air going INTO the hole. Only 1 is connnected to piping to carry the condensation run-off into the drain in my floor. After reading the installers guide, I couldnt make heads or tails if that hole is supposed to be sealed or not (there is mention about when to do it such as "downstream" and stuff, but I have no idea what that even means!). So, do I live with the "loudish" noise or do I seal it?

Also, I have some cheap Flanders filters (white EnergyAire "Basic Pleat" from Lowes I believe) that I put in my returns just give that little bit of extra filtration. Over the course of about 4-5 months they start looking dirty. The returns were not designed to have filters in them, but 16x16 filters in my 2 returns fit perfectly (pressure fit). Should I keep them in there, or will they restrict airflow too much?

Thanks.

[dash]

Very few duct systems can handle the PD(pressure drop) of 1" pleated filters,adding extra filters is unlikely to be a good idea.

You should have the ESP(external static pressure,think resistance to air flow),tested by a Pro,and compared to the fan data for your system,to see if you are getting the minimum required air flow,to protect the equipment and get the SEER you paid for.

Call you Pro and ask if they can do this,if not keep dialing until you find one knowledgeable in this area.

[Border411]

OK....any info about the weep hole?

[DanW13]

If this is a high efficiency furnace the working parts of the furnace should be sealed form the acess door orfromthe filter rack. But if your referringto the lines going to the coil which sits above the furnace blower then yes those holes should be sealed off using a special clay to close them up.

[Border411]

This is a small hole right at the bottom of the unit near where the filter sits. On the right hand side are 3 holes to connect PVC piping to to carry the moisture taken out of the filtered air to the drain. They are arranged like a triangle. The bottom right one has PVC attached to it. Then, between that and the bottom left hole (which is sealed with a plug), there is a weep hole. In the instruction manual, it states something about sealing that hole with RTV or caulk if it is downstream of something (or close to that as I am not at home with my manual.) That is the hole I am talking about.