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Thread: AC lifespan

  1. #1
    Join Date
    Jun 2005
    Posts
    3
    Bought the house last year. AC seems to be weak - when it is 83(28C) outside it runs constantly to bring house to 76(24C). Unit is KeepRite 15 years old. I've replaced air handler blower (it was drawing more than twice the current it was supposed to) and outside condenser fan motor (too much noise) as well as air filter.
    Strange thing - when the unit is running only top 20-25% of the outside condenser radiator is warm, the rest to the bottom has outside temperature. The exposed copper line that goes into internal evaporator is warmer to touch than the 'hot' part of condenser radiator ~95+(35C+) and not even close to outside temp. Both coils are clean; air handler blower is constantly on 'high'.
    Called couple places for estimate to check/recharge the system and one said that lifespan of the AC is 14-15 years, don't waste money fixing it. Is this really neccessary or it can be tested/recharged to run for a few more years?

  2. #2
    Join Date
    Dec 2004
    Posts
    200
    maybe maybe not, know one can tell until they check the unit to see what the problem is

  3. #3
    Join Date
    Mar 2002
    Location
    Richmond, Virginia
    Posts
    4,264
    It's time to call a professional. Looks like you've done all you can do. You may have invested in some unnecessary components IMO. Start budgeting for a replacement system in the near future as 15 years is about average.
    There is nothing more frightful than ignorance in action....Mark Twain

  4. #4
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,633
    Originally posted by HVAC Pro
    15 years is about average.
    Anecdotal observation or referenceable statistic? I'm just curious. (Yes, yes. Referenceable is not a word. But I use it anyway.)

    In these parts an average AC can go 20 to 25 years without much fuss. But we have relatively mild summers. An AC's life depends on how well it was installed, how well it was taken care of and how much it was used. 15 years is likely an average life for a heavily used machine. Lightly used machines can easily go longer. It often comes down to customer fear. Some simply can't stand the idea that they might waste a couple hundred on a machine that might completely poop out a few months later.

  5. #5
    Join Date
    Mar 2002
    Location
    Richmond, Virginia
    Posts
    4,264
    Originally posted by Irascible
    Originally posted by HVAC Pro
    15 years is about average.
    Anecdotal observation
    Yes. And you're correct. Average life can and will vary depending on location. Of course, I sometimes forget that there is a location other than the one I serve. Kinda get into the habit of speaking with only local implications. I get called on that often.

    Of course there are exceptions to every rule. I replaced a 19 year old Comfortmaker heat pump yesterday. I replaced a 5 year old Lennox HP26 a couple of weeks ago. I've replaced 25 year heat pumps and some that have worn out in 10. The average life of a heat pump in these parts is 12-14 years. Gas furnaces last 15-20 depending on manufacturer and model. Straight cooling should last around 20. But some of the builder grade systems (which makes up 90% of what goes into new construction here) built in the past 10 yrs. just won't hold up.

    Coil leaks, dead compressors, and cracked heat exchangers on systems more than 10 years old in my opinion are candidates for replacement.
    There is nothing more frightful than ignorance in action....Mark Twain

  6. #6
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    5,998
    Originally posted by HVAC Pro
    The average life of a heat pump in these parts is 12-14 years. Gas furnaces last 15-20 depending on manufacturer and model. Straight cooling should last around 20.
    Quite REASONable discussion !
    Your location [ in these parts] is ____ ?
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  7. #7
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Too many variables to tell online. A/c could be undersized. After 15 years I'd be looking for a more efficient and correctly sized replacement. Even if you sell the home, you'll recoup the cost in selling price if you're smart. JMO
    If everything was always done "by the book"....the book would never change.

  8. #8
    Join Date
    Jun 2005
    Posts
    3
    Sorry for not being specific - I'm in Canada, 35 km north of Toronto. Temperature here rarely exceeds 90(32C) in a daytime and it goes down to 75-80(23C) at night.
    What suprises me about this unit is that it doesn't use the whole condenser coil, only top part of it. The high pressure pipe from compressor splits into 2 halves before going into condenser and then these 2 parts are connected together at another end where the liquid refrigerant is supposed to come out.
    Anyway, as I've said it can barely bring the house down 8 (4C) degrees relatively to the outside. It has 28000 BTU resiprocating compressor. House is 3200 sqf. Regardless of the fact that it seems undersized I'm still pretty sure that aggregate change of the refregirant should happen in the otside coil, not in the returning line itself. I'll probably ask 'professionals' to perform basic pressure test first and if it is simply undercharged I'd rather charge it than throw away - it is working the second summer so far. Somehow I've got the impression that they don't want to bother and much more willing to replace the whole unit. If it goes this way I can easily see that new one could require the new furnace as well on the grounds that "new evaporator doesn't fit" or something like that.

  9. #9
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,545
    Call for service, but thats a very small unit for that square footage.
    Aire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced

  10. #10
    Join Date
    Mar 2002
    Location
    Richmond, Virginia
    Posts
    4,264
    Originally posted by dan sw fl
    Originally posted by HVAC Pro
    The average life of a heat pump in these parts is 12-14 years. Gas furnaces last 15-20 depending on manufacturer and model. Straight cooling should last around 20.
    Quite REASONable discussion !
    Your location [ in these parts] is ____ ?
    My location is Richmond, Virginia.

    Sorry, seems my profile was left altered during the site transition. I think I have it updated adequately now. Thanks for making me aware.
    There is nothing more frightful than ignorance in action....Mark Twain

  11. #11
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,633
    What are you talking about King?! That's the old 1400 square feet per ton rule. Everyone knows that rule.

    What's the model number of the AC Mike? I have a hard time believing it's that small.

  12. #12
    Join Date
    Jun 2005
    Posts
    3
    Originally posted by Irascible
    What are you talking about King?! That's the old 1400 square feet per ton rule. Everyone knows that rule.

    What's the model number of the AC Mike? I have a hard time believing it's that small.
    KeepRite
    CA2030QKB1

    If my memory serves right this I took from the shield on the compressor:
    208/230 60 Ph1 LRA 79 RLA 14.4
    H20B 283ABCA (High Temp, R22, Standard Basic, Reciprocating, 28000BTU,
    Permanent Split Capacitor, Internal Line Breaker, 7.5"X7.5")
    BM701355

    I can't tell you if this compressor was always there or it was replaced at one point - I have no service history on the unit whatsoever.

  13. #13
    Join Date
    Feb 2002
    Location
    Yuma, Arizona
    Posts
    921
    Originally posted by HVAC Pro
    Start budgeting for a replacement system in the near future as 15 years is about average.
    In my neck of the woods (or desert- Southwest Arizona) we have a number of old R-500 systems still going.
    Exp: Carrier split system. R-500 !!
    Mod: 3802-A208 Ser: 641165 3Ph, 208vac
    I would say it's about forty years old.
    So I would say they could last 25 years.....

    Yuma,
    What is snow? Is it that white stuff in a freezer?

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