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  1. #1
    Join Date
    Feb 2012
    Posts
    42

    inverter unit pumpdown

    In the process of fixing my flare leak (see the end of
    my other thread ) my tech did something I thought was
    ... not necessarily impossible, but made somewhat difficult
    on the newer systems. He managed to pump down my
    Daikin unit and store most of the refer in the outdoor
    unit, so we could at least look at the flare and make
    sure it was clean and not cracked. There's nothing about
    how to do this in the Daikin docs, and of course with the
    inverter systems no big old-skool contactor to punch and
    make the compressor run. He had me simply ask for lots
    of cool at the stat, closed off the liquid valve, and then
    when the lineset pressure got down to about 30-40 psig
    simply pulled the disconnect and then shut the vapor line.
    He said you can't go to zero because the low-press sensor
    will kick and cause shutdown and a bunch of solenoids
    to open up and lose the pumpdown, so you have to catch
    it just at the right moment and it's not perfect. Guess where
    the rest of the remaining 410a went when we went to look
    at the flare...

    Do y'all think this is kosher on the newer style units?
    If you believe all the manuals the only way to handle
    repairs is recovering the full charge first. I'm still trying
    to learn where by-the-book and real life don't agree.

    Oh, and this time before letting refer back out of the unit he
    actually bought his pump a new bottle of oil so it would
    actually pull down, implying that on that first startup we
    never got anywhere near enough vacuum on the lineset
    to dry it properly. I'm kind of concerned that now there
    might be a bunch of moisture throughout the whole
    system from that. There *are* a bunch of little filter
    dryers scattered around the unit as it comes from the
    factory, but why abuse them right off the line?

    _H*

  2. #2
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,717
    He should recover all refrigerant fix all leaks replace any driers ( if it has any ) vacuum the system to 300 microns and then weight in a new charge of refrigerant .some mini splits have no filter driers

  3. #3
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by hobbit View Post
    I'm kind of concerned that now there
    might be a bunch of moisture throughout the whole
    system from that. There *are* a bunch of little filter
    dryers scattered around the unit as it comes from the
    factory, but why abuse them right off the line?
    There are no factory installed filter dryers in your system, nor do they want them installed during installation or repairs on the system.
    Those little things "scattered around the unit" are just filter screens.

    The good news is that Daikin uses PVE oil instead of POE oil in their R-410a systems.
    While PVE oil absorbs moisture even more readily than POE oil, it is chemically stable in he presence of moisture, so it won't break down and form acids.
    Unlike POE oil, PVE oil will give up its moisture when the system is evacuated.

    Obviously moisture in the system is a bad thing, even if it won't directly cause the oil to break down, but with a system that uses PVE oil, recovering the contaminated refrigerant, doing a proper evacuation, and recharging the system with fresh refrigerant is all that is needed to clean it up.

    If the refrigerant lines are relatively short, the system can loose a good bit of refrigerant before it starts having any affect on the capacity or efficiency of the system.
    It usually has to have lost quite a lot before the system is no longer able to compensate for the lack of refrigerant and starts reporting errors.

    The smaller Daikin systems, like the ductless splits, inverter ducted, SkyAir, and VRVIII-S systems, don't have a charging mode for topping off the charge, so the only "correct" procedure would be to recover the charge, evacuate, and weigh in the correct charge.
    If more government is the answer, then it's a really stupid question.

  4. #4
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    I agree with Mark, the proper procedure should have been to put into "recover" mode where all the EEVs would go fully open, recover what's left, fix the leak then do the evacuation process all over again. Since you have no idea how much has leaked out and the charge is critical, no reason to not do it the correct way and ward off any evil spirits. Hopefully he knows how many feet of piping he has in the system so the correct charge can be calculated........

    Btw Hobbit, you know more about these systems than the guys I work with. Do you need a job?!

  5. #5
    Join Date
    Feb 2012
    Posts
    42
    Okay, good to know about the PVE -- the Daikin doc never mentions
    anything about oil type one way or the other, and I just assumed it was
    POE. Having studied automotive coolant and brake-fluid chemistries
    a little too, I'm just as paranoid as the next guy about formation of acids.

    Thanks for the clarification on what those little bumps in the pipes are.
    They're only about an inch across and maybe three long, copper, and
    don't look like the typical f/d. The diagrams do only refer to them as
    "filter", seeming to confirm all that.

    To work in the field, as fascinating as I'm finding the subject matter from
    my armchair right now, I'd need to go through the whole training mill that
    the *rest* of my home retrofit certainly isn't going to allow me time for at
    the moment. Thanks for that thought, though. Know what I really want?
    I want a Boston-north-burbs tech who's as careful as some of you guys
    to come out and eyeball this setup, and possibly discuss an ongoing
    service relationship. I'm serious about that, and am ready to put down
    some real $ to work with someone I can be truly confident in. Someone
    who won't be scared off by the fact that even *I* know how to put this
    system into all-valves-open vacuuming mode, not that I have any of
    the necessary gear to do any of this work or set things right with this
    particular system myself. Someone who acknowledges that a homeowner
    can determine old envelope heat loss figures, predict new ones, and size
    a system accordingly which is exactly what I've done here.

    My installer did add some more juice, simply by watching the low side
    in cool mode and adding slowly until it stabilized around 150 psig,
    and ventured the guess that I'd lost about a pound out of the 5.1 this
    rig wants in it. I had no choice but to trust his seeming seat-of-the-pants
    experience at that point. It did seem like the lineset was gurgling a little less
    when running afterward, so it might have even been a little undercharged
    when we started it but hey, these systems have generous accumulators and
    should adapt well. The lineset's all of about 17 feet long. I actually own
    a leak detector that's so old I don't even remember where it came from, but
    it detected the 410A leak just fine and there's no sign of that after the flare
    was examined and re-torqued, but no effort to Nylog the thing was made
    either even though we actually *talked about that* while the guy was here.

    If PMs work here then feel free to poke me, or we can figure out how to
    trade email addresses or something. You'd even get to tour all the rest of
    the craziness in the overall reno project, which any energy wonk would
    have a total ball with.
    [*Edit*": I cannot receive PMs on this system. What's an acceptable way
    to establish contact??]

    _H*

  6. #6
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by hobbit View Post
    My installer did add some more juice, simply by watching the low side
    in cool mode and adding slowly until it stabilized around 150 psig,
    and ventured the guess that I'd lost about a pound out of the 5.1 this
    rig wants in it. I had no choice but to trust his seeming seat-of-the-pants
    experience at that point. It did seem like the lineset was gurgling a little less
    when running afterward, so it might have even been a little undercharged
    when we started it but hey, these systems have generous accumulators and
    should adapt well. The lineset's all of about 17 feet long.
    Oh boy...

    The thing about the system is that it will compensate, within a fairly broad range, for a low refrigerant charge.
    They don't shut down and generate an error code until the refrigerant charge is to low for it to safely operate the compressor.

    With only a 17' lineset, the system would most likely operate just fine, and at or near full capacity, even if it is a pound or two short of refrigerant.
    It could loose half its charge and still happily continue going.

    Looking at pressures, especially just the suction pressure, is meaningless when you are dealing with a variable capacity system.
    If more government is the answer, then it's a really stupid question.

  7. #7
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    Wow, unreal. It only holds a little over 5 pounds and he didn't pull it all? Yikes. That'd be a really long commute from bean town to where I live everyday, haha.

  8. #8
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,717
    Find somebody to come and recover all refrigetant pull a deep vac and weigh in a new charge

  9. #9
    Join Date
    Feb 2012
    Posts
    42
    Hmm. That's one of the issues, finding someone who is willing to
    do all that due diligence. The guy who installed this rig for me
    apparently isn't.

    It probably seems like I'm going too hard on this guy, though. For
    all I know he's reading all this stuff too. To be totally fair, he and his
    helper were here for a week doing all phases of this install -- they
    did a great job on all the tin-knocking to get this thing connected
    into my existing ductwork, and worked around various issues we both
    had finding compatible electricians to get power to it all. He let me
    be picky about how to spec and install the HRV, with the understanding
    that I was going to do plenty of experimentation with airflows and he
    didn't have to declare that part of the job anything like "complete".
    I was just a little bothered by what I (and some of you) perceived
    as a rather cavalier approach toward certain operations on the heat
    pump system itself. Recall that I've been asking for a sanity-check
    on that, acknowledging that someone's training being a little out of
    date doesn't make them a total f-up on the job. All I want here is a
    second opinion (and possibly some hands-on corrective action) from
    other Daikin-savvy professionals who can understand where I'm
    coming from as the "educated client". I hope there's no harm or risk
    of jeopardizing a working relationship from that.

    That aside, how 'bout my original question? Is it okay to pump down
    an inverter-drive unit in the way detailed above, either on a minisplit
    or a ducted unit (which is what I've got, shouldn't really matter) ??
    The manuals are all like "never just cut power to the system!" but
    apparently their writers haven't lived through New England ice
    storms, i.e. like it or not it'll happen sometimes.

    _H*

  10. #10
    Join Date
    Aug 2009
    Location
    Fern Creek , Kentucky
    Posts
    309
    Hey Hobbit !!!
    Being you emailed this Nice Comment to my Personnel Email instead of Commenting to the Thread on here generated by another user not me , and Taking the Time to Follow the New Thread after we got the New CTR Appion plungers , and when I tried to respond to your Comment that you Posted to my Personnel Email , your Provider Rejected me , being you don't have your Private Messages on HVACTALK I figured I would Bring it here !!!
    I know this does not Pertain YOUR Thread , I am sorry to Post here but I am sure you Wanted my Response , being you took Time out of your Busy Day to respond to me in such a Professional Manner !!!


    ----- Original Message -----
    From: "*Hobbit*" <removed e-mail>
    To: fritz
    Sent: Saturday, July 7, 2012 12:26:07 AM
    Subject: appion

    Hi, does this address actually work? I just found your vid on Appion CRT
    failures, and could only think that a little analysis could have found
    the real issue in a couple of minutes and shortened the video to about
    four minutes instead of a half-hour of blind trying about 20 times.

    How about this? Have Eddie do a short, to-the-point presentation, since
    he was clearly able to think through and pinpoint the problem quickly [but
    not until 30+ minutes into your vid], and then you'd have something the
    Appion folks could take seriously. Oh, and buy yourself a camera tripod...

    _H*

    Hey Hobbit !!!

    I think we will be just Fine , Appion (Christian) took it Serious enough to mail me 6 more New Plungers , OVERNIGHT after that Video ,with the NEW O Rings at the end of the Plungers ...
    and write me a Nice Letter for doing the Video , and the Follow up Video where Me & Eddie are showing them working and Proving that you can pull them down to 20 microns with all my Appion Gear.
    You might want to Read the Comments section , where Appion is one of my loyal Subscribers here on Youtube !!!
    You might want to Check that one out , that one is 60 minutes Long and I have the Camera strapped to my Dog Sarge Not a Tripod !!! ROFL ...

    If you don't like em don't watch em , I have over 200 Videos , and 900 subscibers that Enjoy my Videos , just look at the Comments !!!

    My Format is my Format , let me know when you Post your First Youtube HVAC video , and i'll be Glad to give you any Pointers you need , and i'll Steer some of the HVAC Fellers from HVACTALK and on Youtube your way !!!

    Oh , I guess what i'm trying to say in a Nice way is , if I want your Opinion i'll give it to ya !!! LOL ...

    Take Care ,

    Fritz ...









    Quote Originally Posted by hobbit View Post
    In the process of fixing my flare leak (see the end of
    my other thread ) my tech did something I thought was
    ... not necessarily impossible, but made somewhat difficult
    on the newer systems. He managed to pump down my
    Daikin unit and store most of the refer in the outdoor
    unit, so we could at least look at the flare and make
    sure it was clean and not cracked. There's nothing about
    how to do this in the Daikin docs, and of course with the
    inverter systems no big old-skool contactor to punch and
    make the compressor run. He had me simply ask for lots
    of cool at the stat, closed off the liquid valve, and then
    when the lineset pressure got down to about 30-40 psig
    simply pulled the disconnect and then shut the vapor line.
    He said you can't go to zero because the low-press sensor
    will kick and cause shutdown and a bunch of solenoids
    to open up and lose the pumpdown, so you have to catch
    it just at the right moment and it's not perfect. Guess where
    the rest of the remaining 410a went when we went to look
    at the flare...

    Do y'all think this is kosher on the newer style units?
    If you believe all the manuals the only way to handle
    repairs is recovering the full charge first. I'm still trying
    to learn where by-the-book and real life don't agree.

    Oh, and this time before letting refer back out of the unit he
    actually bought his pump a new bottle of oil so it would
    actually pull down, implying that on that first startup we
    never got anywhere near enough vacuum on the lineset
    to dry it properly. I'm kind of concerned that now there
    might be a bunch of moisture throughout the whole
    system from that. There *are* a bunch of little filter
    dryers scattered around the unit as it comes from the
    factory, but why abuse them right off the line?

    _H*
    Last edited by jpsmith1cm; 07-10-2012 at 09:55 PM. Reason: Removed E-mail

  11. #11
    Join Date
    Feb 2012
    Posts
    42
    Sorry, it probably came out a little wrong as can often happen in
    email. And yes, the spam-filters are pretty strict over here, but
    the rejection should have indicated something about why it
    happened...

    I did go through the whole video, and later found the followup.
    Y'all taught me more than I ever thought possible about core
    removal tools, in fact, but there were parts in the video where I
    was thinking "pull up! pull up! I wanna *see* what he's holding!"
    you get the idea. Understood that a hat-cam isn't the ideal
    targeting device.

    Being the analytical sort that I am, I would have immediately
    been digging into the relevant parts going "okay, *why* is it
    not grabbing the core, what's it actually supposed to do?"
    which might be what you've got some other viewers wondering
    for a while too. Well, we all think differently and take different
    approaches to a problem, I guess.

    This is indeed straying far afield of my original question,
    though. Some of it and some of my other AOP questions
    boil down to "what shortcuts can my contractor get away
    with that I *shouldn't* worry about?" Opinions vary quite
    a bit, and I wish I had a better sense of what procedures are
    likely to affect the service lifetime of any given system.
    Especially the newer ones with much more resilient
    control strategy. I really want to have a lot of respect
    for the HVAC field as a whole but y'all know there are
    some real horror stories out there. What's a homeowner
    to do...

    _H*

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