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  1. #1
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    Aug 2019
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    Carrier/Bryant/Payne FV4C, 002 vs 005

    How big of a difference is there between the noise made by the 002 and 005 variants of the FV4C when operating at 1050CFM (the nominal 100% speed for 3 ton operation) and 840CFM (when operating in 'dehumidify' mode at 80% nominal speed)?

    I see from Carrier's data sheet that there's officially NO difference between the noise produced by the 002 and 005... and I don't believe it. The only way to pump 1050CFM through rectangular tubes of differing cross-sectional area is by increasing its velocity through the smaller tube. Does Carrier seriously expect anyone to believe that the motor in the smaller one, spinning faster and working harder to blow the air at higher velocity doesn't make even a fraction of a decibel more noise?!? Or that there's no added noise from higher-velocity air entering through a smaller return hole at the bottom, and exiting through a smaller supply hole at the top?

    The big question is... how noticeable is the difference between an 002 and 005 in real life? For example... if I were:

    * In bed,

    * on the other side of a closed door,

    * the door is adjacent to the closet where the air handler is located,

    * the closet has closed bifold doors with plantation shutters that allow air to flow freely, but also provide no meaningful noise abatement

    ... would I be likely to notice the difference in noise between the 002 and 005 if it were running at 1050CFM? How about at 850CFM?

  2. #2
    Join Date
    Dec 2007
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    There should be no noticeable difference. Will there be, probably.

    Other factors will influence the noise, like duct work.

    Look at the return opening and the supply opening of the air handlers. How much difference is there?
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  3. #3
    Join Date
    Feb 2010
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    The FV4C 002 through 005 carry the exact same horsepower motor, just different motor programming for fan speeds. The 002 is a physically smaller air handler than the 003 and 005 and has a 2 ton txv while the 005 has a 4 ton txv. What size outdoor unit are you matching it up with?

  4. #4
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    Aug 2019
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    85% likelihood of 3 ton, 15% likelihood of 2.5 ton. My old system was 3 ton & its capacity as of a year ago was absolutely perfect... but its capacity was *also* compromised to some unquantified extent.

    * low side pressure was too low, but couldn't be increased without pushing high side pressure above its safe limits.

    * condenser coil had a leak repaired ~2 years ago by cutting out the leaking section & replacing it with an equal length of copper tubing. It fixed the leak & bought me another year and a half of use, but almost certainly impacted its performance.

    * condenser fins were badly corroded, and 3-7% were crumbled away outright.

    * evaporator coil was dirty, but too fragile to risk disturbing (multiple formicary corrosion leaks that were successfully patched with leak stopper, but I was warned to not let ANYTHING disturb the coil -- ESPECIALLY-- cleaning, unless I was ready to replace it immediately if necessary, because any stress at all would have likely opened new leaks in weakened areas.

    So... I'm sure my old unit wasn't operating at 3-ton capacity, but I'm not sure whether it was compromised to the point of acting like a de-facto 2.5 ton unit, or whether its problems mainly just caused it to work harder & increased its electricity usage.

  5. #5
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    Aug 2019
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    When an installer buys a FV4C, does it come from the factory with its coil & TXV already in place, or is it like buying a barebones PC, where the fan & chassis comes in the "FV4C" box, but the coil and TXV are purchased separately? Likewise, is there just one TXV model for the 002 & one for the 005 that both have a ~1.5-2.0 ton adjustment range, or are there more variants with smaller adjustment ranges?

    It also just occurred to me that the repairman who complained about the irreconcilable low & high pressures probably could & should have just adjusted the TXV to fix the problem, and totally dropped the ball (assuming "adjust the TXV" is a fairly easy thing to do, and wouldn't have cost more than the benefit would have been worth).

  6. #6
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    Feb 2010
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    Everything comes as a package based on the model you buy.

    Most residential TXVs are not adjustable. Unless Carrier changed anything in the last year theirs are also not adjustable.

  7. #7
    Join Date
    Sep 2007
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    State College, PA
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    Quote Originally Posted by FlyersFan View Post
    Everything comes as a package based on the model you buy.

    Most residential TXVs are not adjustable. Unless Carrier changed anything in the last year theirs are also not adjustable.
    This is correct. The TXV is not adjustable.
    Can someone please explain to me -
    Why is there never enough time to do it right the first time, but plenty of time to do it twice?


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  8. #8
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    Aug 2019
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    > theirs are also not adjustable.

    Hmmm. That actually seems to be a compelling argument in favor of the 002, and against the 005, then.

    One idea I came up with to try when my future condenser finally dies from coil cancer after its warranty ends (since nobody is capable of manufacturing coils that last anymore, and replacement coils for an EOL'ed unit apparently cost more than a new unit does and take weeks to obtain) is to have the repairman just seal off and eliminate the leaking coil circuit entirely.

    It would instantly slash at least 25% of the condenser's capacity, and probably accelerate the compressor's demise by throwing the compressor wildly out of spec... but at that point, who cares? It's going to the landfill within a few weeks or months anyway. In the meantime, it would buy me time to properly research replacement options, instead of being forced to settle for whatever the repairman can get his hands on immediately, at any cost. The cost part would suck, but the "settle for whatever is available today" part is what would torment me and leave me with at least a decade of buyer's remorse(*).

    If the 005 can only go down to 2.5 tons, cutting out 1/4 of a 4-ton coil and reducing it to a de-facto 2.25-ton coil might be a real problem. Since the 002 can go down to 1.5 tons, even a completely butchered 3-ton coil that was literally missing TWO of four or five circuits would probably still be able to limp along for at least a few weeks while I researched replacement options.

    ---

    (*) I'm sure that by now, everyone thinks I've WAY over-thought this purchase... but on the bright side, even if it ends up sucking, I'm unlikely to end up suffering from buyer's remorse for the next 10-20 years, because at this point I've reached the sad conclusion that while the FV4C is far from perfect, everything ELSE is worse, and there ISN'T an alternative model by Carrier or anyone else that I'd actually be more satisfied with. I'll be frustrated because it's not perfect, but at this point I've mostly concluded that it's the best I can actually get.

  9. #9
    Join Date
    Aug 2002
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    The fv4 is a solid airhandler but I hardly ever use it anylonger since it is not communicating. The communicating version is so much more adjustable and has more capabilities. And the communicating version is the same cost just needs a communicating thermostat with it.

  10. #10
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    Quote Originally Posted by Pantherkitty View Post
    > theirs are also not adjustable.

    Hmmm. That actually seems to be a compelling argument in favor of the 002, and against the 005, then.

    One idea I came up with to try when my future condenser finally dies from coil cancer after its warranty ends (since nobody is capable of manufacturing coils that last anymore, and replacement coils for an EOL'ed unit apparently cost more than a new unit does and take weeks to obtain) is to have the repairman just seal off and eliminate the leaking coil circuit entirely.

    It would instantly slash at least 25% of the condenser's capacity, and probably accelerate the compressor's demise by throwing the compressor wildly out of spec... but at that point, who cares? It's going to the landfill within a few weeks or months anyway. In the meantime, it would buy me time to properly research replacement options, instead of being forced to settle for whatever the repairman can get his hands on immediately, at any cost. The cost part would suck, but the "settle for whatever is available today" part is what would torment me and leave me with at least a decade of buyer's remorse(*).

    If the 005 can only go down to 2.5 tons, cutting out 1/4 of a 4-ton coil and reducing it to a de-facto 2.25-ton coil might be a real problem. Since the 002 can go down to 1.5 tons, even a completely butchered 3-ton coil that was literally missing TWO of four or five circuits would probably still be able to limp along for at least a few weeks while I researched replacement options.

    ---

    (*) I'm sure that by now, everyone thinks I've WAY over-thought this purchase... but on the bright side, even if it ends up sucking, I'm unlikely to end up suffering from buyer's remorse for the next 10-20 years, because at this point I've reached the sad conclusion that while the FV4C is far from perfect, everything ELSE is worse, and there ISN'T an alternative model by Carrier or anyone else that I'd actually be more satisfied with. I'll be frustrated because it's not perfect, but at this point I've mostly concluded that it's the best I can actually get.
    What the heck are you rambling about?!
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  11. #11
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    Aug 2019
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    The problem is, I'm developing my own thermostat controller for it... in no small part, because non-Carrier thermostats don't properly implement support for super-dehumidify mode, and Carrier's OWN thermostats implement support for it in a completely brain-damaged, crippled, and stupid way.

    * Cor won't allow you to set a dehumidification target of less than 45%. My own personal daytime comfort level is 75F @ 31-34% (72F @ 31-34% at night). For me, 45% RH isn't an aspirational goal... it's wet, sticky, and slimy hell that urgently demands aggressive dehumidification.

    * Cor uses super-dehumidify strictly with cool-to-dehumidify. My thermostat will make use of it "opportunistically"... if it's cool enough to achieve and maintain the set point using ONLY super-dehumidify mode (ensuring it runs at least 10 minutes and at most 20 minutes, with 10-30 minutes of recovery time between runs for the coil-frost to melt), it will. Otherwise, it'll begin the run in regular 'dehumidify' mode, and switch over to super-dehumidify mode for the last 10 minutes of the run (once again, observing a minimum recovery time of 10 minutes to give the frost time to melt.

    * Cor makes zero attempt to prevent the coil from freezing up on nights when it's cold outside, but humid. My controller will prevent low-ambient freezing in three ways. First, if it sees the air coming off the coil (or the evaporator coil itself) getting too cold, it'll increase the blower speed and turn on the heat strips. Second, I'll have a portable dehumidifier in the closet next to the air handler that my controller can power up on demand (by spoofing its infrared remote control) to wring some extra humidity out of the air AND increase the amount of heat in the return air entering the FV4. Third, if despite its best efforts it sees the temperature fall below 34F, it'll abort the run, log the exception and alert me, and keep the system off for 30 minutes to give any frost that built up time to melt away before the next run.

    I'm pretty sure the first two strategies will be good enough to avoid having the coil even be in danger of freezing, but if after a winter or two I decide it's not quite good enough, I have a fallback plan: replace the condenser fan's motor with a 2-speed PSC & wire up some additional logic so my controller can drop it to half speed only on those rare nights when it's too cold to run it normally.

    * Cor won't use electric reheat with cool to dehumidify. My controller won't do it gratuitously (I really don't want to end up with a $400 electric bill), but I'm not afraid to do it in small doses when appropriate, either. As I told someone, using electric reheat with cool to dehumidify in Ohio would bankrupt you... but using it sparingly somewhere like Miami for a few hours per year is a nifty way to get the performance of a thousand-dollar whole-house dehumidifier in return for occasionally forking over an extra $10-25 to FPL.

    So... that said... I haven't been able to find any documentation that gives me confidence that I'd be able to achieve the same level of control I know how to get from a FV4 using a FE4/Infinity. I found two projects at Github (Infinitude and Infinitive), but neither one appears to have reverse-engineered Carrier's RS485 protocol enough to be capable of directly controlling the FE4's blower speed.

    I had high hopes for Goodman's old AVPTC with ComfortNet since ComfortNet is based on ClimateTalk, itself a nominally open standard... but once again, brick walls everywhere. I found documentation for the wire protocol itself, but nothing about the AVPTC's control registers. A shame, because you can actually get a pretty sweet deal on a new-old-stock AVPTC right now.

    Of course, ComfortBridge is just a hot mess & case study in how to **** things up as thoroughly as possible. I'm sure that the hardware itself probably offers at least as much direct control via TCP/IP as Carrier's does via RS485, but as far as I can tell, nobody has come anywhere close to reverse-engineering how it works yet... and nobody from Daiken has leaked the docs yet. Ten years from now, there might be a half-dozen repos on Github with direct programming information for ComfortBridge's non-public API... but right now, it looks pretty brain-damaged and crippled. Worse, ComfortBridge TODAY depends upon Daiken's web service for both authorization to use it AND its actual operation. Even if I can manage to score credentials today to unlock the system's "installer only" features, there's no guarantee Daiken wouldn't take them away at some point in the future and leave me with a crippled system that no longer satisfied me. Or worse, no guarantee that Daiken wouldn't decide ~15 years from now that it's "End of Life" and shut down the web service, leaving every remaining ComfortBridge limping along with only limited functionality. Put another way, I've had way too many products turn into paperweights over the years because the vendor decided that keeping an old server running no longer aligned with this weeks Strategy™. I'm not about to gamble on having it happen to my air conditioner until someone hacks it enough to let me keep it running on my own long after the manufacturer itself has lost interest in supporting it.

  12. #12
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    Aug 2019
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    > What the heck are you rambling about?!

    I think you know exactly what I'm talking about, but I'll simplify it for you. I'm assuming my new system is going to suffer from coil rot and be as unreliable as my old one was, and brainstorming strategies to avoid having the same thing happen to me again.

    * 10+ years from now, when my new condenser is out of warranty, it's probably going to develop a coil leak that can't be properly repaired. If history is any guide, a replacement coil will be outrageously expensive and/or unavailable without several weeks of delay (assuming a replacement coil is available at all).

    * When the system ends up in that hopeless, irreparable state, instead of conceding immediate defeat and desperately agreeing to buy whatever replacement is available immediately, I can have the leaking coil circuit just sealed off and abandoned, so the system can limp along for the remainder of its working life at reduced capacity (3 remaining coil circuits instead of 4) while I shop for its replacement at my leisure.

    * If a 3-ton condenser unit with 4-circuit coil has one of those circuits sealed off, it'll be reduced to at most 75% of its nominal capacity. Basically, it'll become a 2.25-ton unit.

    * The TXV on a FV4C-002 can apparently handle anything between 1.5 and 3.0 tons. 2.25 tons falls between 1.5 and 3.0, so it might be OK.

    * The TXV on a FV4C-005 can apparently handle only condensers between 2.5 and 4.0 tons. 2.25 tons is less than 2.5 tons, so it probably wouldn't be OK.

    * The remaining lifetime of a system resurrected in that manner probably wouldn't be long, and it probably wouldn't run well... but it would at least give me the satisfaction of knowing I got to wring every last possible bit of value from it before conceding defeat and buying a new one. I'd also be less likely to suffer from buyer's remorse, because I could take my time and research its replacement properly instead of having to take whatever I can get immediately just to make the house habitable again.

    Put another way, I bend over backwards to avoid making the same mistake twice. I know how my old system failed, so I'm making a point of trying to either keep my new system from failing again in the same way, or to find ways in advance to minimize the future cost of those failures when possible. I'm converting from a package unit to a split system so a future condenser coil leak won't force me to replace the air handler, too (limiting the scope of damage from that single point of failure by isolating it to a single subsystem). Hacking up the coil to just seal off a leaking circuit and resurrect an otherwise-dead system for a zombie-like encore performance was just an idea I came up with later (sadly, too late to try on the system I'm replacing). The idea might work with an 002, but probably wouldn't work with an 005, for the reasons identified above.

  13. #13
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    Mar 2016
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    I quit reading half way through your rambling about the super dehu thermostat your going to build.

    Have you thought about about a whole house dehumidifier?????


    Sent from my iPhone using Tapatalk

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