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  1. #1
    Join Date
    Jan 2007
    Posts
    18

    Central Air Novice---questions within

    1st off, my basement unit stopped blowing cold air last night. Having some experience with a window unit I checked the filter. Filter was clogged and the Condenser(?) was iced up on both sides and not allowing air to flow through, probably caused by the dirty filter right? Size is 16"X20"X1". What is a good filter replacement? This looked like it was constructed of a weaved fiberglass. I know here at work we have a pleated(?) filter.

    Also, I noticed that cool air was leaking out small little holes in and around the unit....should those be sealed up with tape?

    The upstairs unit is in the attick. I checked the filter there and it looked clean but the size is 16"X25"X1" and it was crushed to fit. I measured the opening and the 16" wide was more like 15" 13/16's of an inch. Should this be rounded down to say a 15.75" Filter?

    Sorry for the newb questions but this is my first experience with Central Air systems.

  2. #2
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,368
    A dirty filter can definitely cause problems. When's the last time it was changed? A blue fiberglass or standard pleated filter (rounded pleats that aren't as restrictive as the 3M-type pleats). Let the system thaw out (the fan can help) and then change the filter. If it continues to freeze up, it's time to call for service as something else is causing the icing.

    Leaks should be sealed as much as possible. A tiny leak here or there isn't the end of the world. Many indoor units do leak out small amounts of air at some places. If the leaks are on the ductwork, you can use foil tape.

    As for the upstairs unit, it might be meant for a 15x25x1 filter (may be more difficult to find, hence the 16x25x1 being slammed in ).

  3. #3
    Join Date
    Jan 2007
    Posts
    18
    Ryan, thanks for the respons. Yea, they are just small holes/gaps in the sheet metal of the unit.

    No idea when it was last changed. We moved into the house in April and it was there. There is only one filter in the basement. In the attick there are three but the on in the unit was crushed to fit and the other two replacements certainly were not the correct size for the unit.

    So a Blue or pleated are best? I did shut off the unit to let it thaw overnight. I plan on stopping off to day on my way home to get some filters. I'm thinking I go a tad smaller than the filters currently installed.

  4. #4
    Join Date
    Mar 2008
    Posts
    205

    There are pleated filters that aren't that restrictive

    Quote Originally Posted by mrgto View Post
    Ryan, thanks for the respons. Yea, they are just small holes/gaps in the sheet metal of the unit.

    No idea when it was last changed. We moved into the house in April and it was there. There is only one filter in the basement. In the attick there are three but the on in the unit was crushed to fit and the other two replacements certainly were not the correct size for the unit.

    So a Blue or pleated are best? I did shut off the unit to let it thaw overnight. I plan on stopping off to day on my way home to get some filters. I'm thinking I go a tad smaller than the filters currently installed.
    Beenthere told me that if the pleats have a sharp angle from the apex to the bottom of the pleat, its too restrictive. I'd look at Lowe's, HD for filters. Also, one of the guys on here suggested looking into Nordic Air (12 MERV) very good. Mine fills up fast so its imperative to change it every month.

    I'll put up w/a bit of restrictiveness, to keep crap off the blower wheel and coils and from blowing back into the house. That's just me.

  5. #5
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,368
    You want the right size filter. So if the downstairs is right, then I wouldn't go any smaller. Some pleated filters can be restrictive. If you get a pleated filter, don't get the 3M kind. Look for the pleated filters that have more round pleats. Probably better off going with the blue spun fiberglass filters and changing them monthly.

    I use standard pleated filters from Flanders. They work well--MERV 8.

  6. #6
    Join Date
    Aug 2003
    Location
    Lincoln, Nebraska
    Posts
    1,051
    Stay away from the 3m filterette pleated filters as these will cause you problems.

    Filters come in standard sizes. A 15.75" filter would need to be special made. A 16" filter will measure less than 16" so it is supposed to fit. Maby the filter cabinet is made wrong.
    Its a good Life!

  7. #7
    Join Date
    Jan 2007
    Posts
    18
    OK, I bought the cheap blue fiberglass filters. Changed out the very dirty one.

    Turned the AC on, stat said 81 in the house. Now before the ice over, when the AC was on, the rooms would cool right down. Last night after 2hrs the temp had only dropped to 78 from 81...it was COOL air and flowing well but not COLD AIR like previously.

    What happened?

  8. #8
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,368
    Give the system time to cool the home down. When it has a high heat load, 3 degrees in 2 hours does not sound unreasonable. Can you take the temperature of the air coming out of the registers?

  9. #9
    Join Date
    Jan 2007
    Posts
    18
    Quote Originally Posted by RyanHughes View Post
    Give the system time to cool the home down. When it has a high heat load, 3 degrees in 2 hours does not sound unreasonable. Can you take the temperature of the air coming out of the registers?


    The air coming out used to be much cooler before the system froze up the other day.

  10. #10
    Join Date
    Jan 2007
    Posts
    18
    Anyone else? Gussing I'll have to call someone out to take a look at it.

  11. #11
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,288
    Quote Originally Posted by mrgto View Post
    Anyone else? Gussing I'll have to call someone out to take a look at it.
    I take it you've been running it since you thawed out the coil and you can't reach the temperature you want.

    Are you sure it has not iced over again?

    If it hasn't, be prepared to receive some tough news from your service technician. It may be nothing, it may be a blown compressor. The latter is possible whenever a coil freezes over due to liquid refrigerant returning to the compressor, which it is not designed to handle.

  12. #12
    Join Date
    Jan 2007
    Posts
    18
    Quote Originally Posted by shophound View Post
    I take it you've been running it since you thawed out the coil and you can't reach the temperature you want.

    Are you sure it has not iced over again?

    If it hasn't, be prepared to receive some tough news from your service technician. It may be nothing, it may be a blown compressor. The latter is possible whenever a coil freezes over due to liquid refrigerant returning to the compressor, which it is not designed to handle.

    Yes we have run it....I haven't looked to see if it was iceing over again...I'm guessing not since airflow has moved very well since I changed out the filter.

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