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  1. #1
    Join Date
    Jun 2005
    Location
    New England
    Posts
    906

    Time to replace the system, or maybe not?

    Hi - glad I found this forum, I've looked at some similar threads, but I think my situation is a bit different...
    -----
    I live in New England, have a 2800sq ft "multi-level" house (four 1/2 levels incl. basement), and have an 18 year old 4-ton York system, with the air-handler and duct work in the attic (various tricks with ducting through closets and such gets cool air to every level). Knock wood, it has never given me trouble or needed any maintenance, and York claims it could last another 8-10 years. I had it checked out recently - coils were clean, freon was fine, differential across air-handler was 12DegF.

    The only 'problem' I've had over the years is that when outside temp <72, and it's humid, the system can cool before it has really dehumidified.

    However, I really believe (though I can't prove it) that its warm weather (outside temp >= 85) performance isn't what it used to be. On a hot day, the compressor runs continually all day, and the inside temp never gets below 75 (for all the energy spent, it's not really comfortable, and that's a shame - we usually keep the house at 72DegF).

    When I first got the system, I could come home at the end of a hot day (no one was home during the day back then), turn the system on with the house hot, and it would be comfortable in under 45 minutes.

    So maybe, despite the temp across the air-handler, SOMETHING is degrading, and it's time to replace. Or maybe I'm just more sensitive to hi-temp these days... 8-}.

    I know a new system will be more energy efficient, but should I really expect a noticable performance improvement in a new system? (I though 15DegF was ideal across the air-handler). If so, what are the most reliable systems out there? I would expect to stay with 4-ton (otherwise during the cooler days it will cool WAY too quickly).

    Any, all suggestions welcome, I need to figure out what I should be focusing on here.

    Thanks
    /j (a bit warm in NE)







    [Edited by jeffw_00 on 06-05-2005 at 06:42 PM]

  2. #2
    Join Date
    Sep 2003
    Posts
    1,311
    12 temperature drop across the air handler is too low. In humid areas about 21 is more appropriate. Either there is a mismeasurement on the temperature or something is wrong with the system, such as compressor failing, low on refrigerant, TXV malfunction, etc. Try to find someone who can properly measure and diagnose the system.

  3. #3
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    12 is low ,I'd expect more.which would dehumidify better.


    A new system can include a two speed compressor ,which can run in high when it's hot,and in low about 70 or 80% of the time to provide the best in dehumidification.Many owners find they run the tsat a few degrees warmer with lower humidity.

    Variable speed fan,in your new system,will provide the required air flow for efficiency,even as the filter becomes dirty.Plus slow the airflow,to dehumidify as needed.Plus on a good duct system,it costs less to run,then what you have.

    SEER today ,is likely available a double the SEER you have,so another way to save.



    Carrier has a great Control system,to dehumidify,it's called Infinity,do a search on this site(Infinity) ,to see what other homeowners think of theirs.


    Look for variable speed fan(air handler),and good dehumidification controls in what ever brand you may purchase,as a minimum.

  4. #4
    Join Date
    Jun 2005
    Location
    New England
    Posts
    906

    Time to replace the system, or maybe not?

    Thanks dash - de-humidification isn't that big a problem, and I'm not sure I want the lower speed fan (we run the fan at high speed all the time to run the air through the spacegard filter to reduce allergens, i've tested with and without, it does make a difference!). Still, I'm hoping there's a repair that will get the system going again. But If not - what are the most reliable brands??? (reliability is more important to me than efficiency, and, to a degree, cost - HVAC contractors are expensive and hard to find around here, so a system that needs no attention is my highest priority).

    THANKS!
    /j

  5. #5
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,656
    IN 18 years you havent had it serviced? and you wonder why it isnt cooling well?

    I think it may be wise to call for service!
    Aire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced

  6. #6
    Join Date
    Jun 2005
    Location
    New England
    Posts
    906
    oh no - I've had it checked over the years, as recently as last summer - never been anything wrong
    /j

  7. #7
    Join Date
    Jun 2005
    Location
    New England
    Posts
    906
    Had a tech out today - said everything looked great, except he said the fan was really dirty. he cleaned it, suggested i use some metal tape to better seal gaps around the air-handler, and said the differential was now 21 DegF.

    So hopefully it's fixed for now. he also mentioned I HAD to replace it by 2010 because the freon it uses will no longer be available. I figure I'll get this season out of it and replace it in Aug -Sept. (is this a good time to shop? - I figure HVAC guys will be less busy then).

    Any recommendations as to system type and brand are appreciated. My #1 priority is RELIABILITY.

    Thanks
    /j

    (and if you're an HVAC guy in the boston "metrowest" area who wants to quote me, - drop me a note!

  8. #8
    Join Date
    Mar 2001
    Posts
    288

    You don't HAVE to replace your a/c unit. Production of it's freon will still be banned, but recycled R22 will be available. Run it til it dies, have it checked yearly, but don't put too much money in that old system.

  9. #9
    Join Date
    Jun 2005
    Location
    New England
    Posts
    906
    Good point. still, I want to replace it _BEFORE_ it dies, as it will probably DIE on the hottest week of the year, and it will take a week to get a contractor to look at it and quote, and another few weeks to get it replaced (contractors are rare and dear around here). 18 years is a good run, and from what everyone's telling me about the new systems, I might not only be more comfortable (from better dehumidification) but also see a significant reduction in my electric bill.

    or am I just rationalizing 8-}
    /j

  10. #10
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635

    recommendations

    The number one factor in system reliability is the contractor that puts it in. When someone inevitably tells you that X brand is junk and that Y brand is twice as good, walk away. They have nothing that sets them apart so they depend on playing marketing games.

    I'll just copy and past a post I gave Mom (not my mom) recently to give you an idea. It's my favorite way of explaining it so far because it involves muscle cars and convicts.

    You're approaching this in a very normal way. Most homeowners focus on brand. But you've got to understand that arguing HVAC differences is like arguing muscle cars. The Ford guy says his will do zero to sixty in 5.2 seconds so the Chevy guy says his will do it in 5.0 seconds and proceeds to do the chicken dance. Who gives a rat's behind? They're both wicked fast! The same goes for HVAC. All of them have their stupid little features that they claim exclusivity on. But so what? Any mainstream brand will serve you well.

    But here's the real catch Mom. Taking our car analogy further: What if instead of that Ford being assembled in a billion dollar plant with a thousand computers and a dozen eggheads watching, that car was assembled by a guy who just got paroled last year and started building cars because of the vocational training he took in prison? You'd stop caring about the brand and features and start worrying big time about the schmuck that's building it!

    That's exactly what you're dealing with Mom. First of all Trane, Carrier or whoever hasn't got one thing to do with the design and installation of the system. They are bit players as far as I'm concerned because all they do is supply parts. Second, that nice Carrier guy or any of the other sales jerks you've met aren't likely to be the ones installing the system. They've got crews and you don't know them from Adam. Third and crucially, painfully FEW do an installation by the book. I'd guess that MAYBE one and if you're super lucky two of the contractors you've met will even come close to doing everything they should. That list could be four times as long if I had the time to write it. And unfortunately, even some of those that do perform truly superior installations will push garbage like this.

  11. #11
    Join Date
    Jun 2005
    Location
    New England
    Posts
    906
    so find a very reputable service/installer and go with his favorite brand, because they're all about the same for efficiency, major features, etc

    I get it
    /j

  12. #12
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,637
    Humidity levels are a big deal with allergies. You need <50% RH to eliminate dust mites in a home. Basements should be <60%RH to avoid high humidity on the cool surfaces like floor and walls in the basement. Low humidity is more important than operating your fan/air filter continuously. Maintaining low humidity, fresh air ventilation, and continuous air recirculation are the critical components for indoor air quality. During wet cool weather, supplemental dehumidification is ideal to have the best indoor air quality.

  13. #13
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Originally posted by jeffw_00
    so find a very reputable service/installer and go with his favorite brand, because they're all about the same for efficiency, major features, etc

    I get it
    /j

    There is certainly a difference between moels and features available within any one brand that are worth looking at.


    Not all here agree that there's no difference at all between brands,and some brands do have features/benefits that might be important enough to some,to choose that brand.


    The design ,install and service after the sale ,is crtainly very important.But is very difficult to determine ,until after the fact.Even if they talk the talk,doesn't mean they will walk the walk.

    In my opinion,Carrier and Trane ,are likely to provide more training ,to get the job done right,and more support after the sale ,if there is a problem.I know this can vary greatly around the country,but that's the way I see it in Florida.

    I give you my sales picth for the systems I like best later,I get all the Flames I can stand,from this.


    Really hope you find the best system and contractor for your needs.

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