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  1. #14
    Join Date
    Jun 2004
    Posts
    43
    Well if you can't tell, I fairly technical and as luck would have it, I am EPA ceritified... I even have gauges (but they are for r134a).

    I hear you on the "beer can cold" approach to diagnostics. I'm sure it works in the vast majority of cases too. Unfortunatly there's the problem children like me that know enough to question the "beer can cold" and if thats the best explanation the tech can offer... I know I picked the wrong tech.

    In any event, I can get a ser of gauges and take some temp readings as suggested. I will likly do that over the weekend and re-post.

    Im very intrigued by Midhvacs notion on attick solar loading.. it really makes sense and given all the time I've spent up there, I certain he's on to something... now I just have to prove it by the numbers.

  2. #15
    Join Date
    Sep 2002
    Posts
    3,708
    Hello Jav,You said they did a load calc,do you have it and
    could you share the #.If not why not go to the bullseye and do one for yourself,then come back and share the result.

    Also model and serial # would help,then we could get a understanding of the capacity of the equipment.

    Now as fars as saying you're not finding a high quality contractor,well I personally blame the ho for that.
    Most are not looking for someone thats does its by the book.

    Right now,I know of several company in my area that do things by the book,and they are setting at the shop with
    nothing to do,but there hardnose in maintain there ethic
    on doing it right.

    We reap what we sow,when price is the only issue,then it
    pushes out the contractor that have highly skill tech and
    gives way to the I dont know parts changer.Sad but true.

    How can we as hvac contractor send our people to schools,
    to make them better at there skill and be more efficent at there jobs,when no one is willing to pay for it?





  3. #16
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,317
    I hear you on the "beer can cold" approach to diagnostics. I'm sure it works in the vast majority of cases too.

    My point is that "beer can cold" does NOT work in the vast majority of cases, particularly with fixed orifice systems.

    Im very intrigued by Midhvacs notion on attick solar loading.. it really makes sense and given all the time I've spent up there, I certain he's on to something... now I just have to prove it by the numbers.

    Radiant barrier is the way to go with attic solar loading. Reduce amount of radiant heat entering attic = reduce amount attic heats up = reduce temperature difference between attic and conditioned space = reduced heat transfer of attic heat into conditioned space, even with insulation. I recently walked through two houses under construction, side by side. One had radiant barrier roof decking (often branded as "Techshield") and the other did not. Neither house had the drywall on yet but the difference between the house with radiant barrier and the house without it was night and day.
    The trick is to size the a/c to a house with radiant barrier properly as it will have an overall reduced sensible heat load. In humid climates this would be problematic unless the coil is sized properly to remove the correct amount of latent (humidity) heat as well as sensible.

    simpleman

    Sounds to me jav is the kind of homeowner you want. Trouble is, how is he to find the good techs, other than the crapshoot method of going through the phone book? If you got companies where you are sitting on their butts with not enough to do while the hacks are out there going and blowing, something's wrong, don't you think? And I mean with the quality minded company's ways of educating their customer base? Yes, you'll always have the penny wise and pound foolish customer, but if the HVAC company spent a little time educating their customer as well as their techs, I think they'd be busy year round. "Call those guys, they know what the hell they're doing!"


  4. #17
    Join Date
    Dec 2003
    Posts
    2,391
    Measure the supply air temperature at the unit. Measure the temperature at the outlets. They should be fairly close. I worked on a system once where the temperature was rising 8-10 deg because the flex had been routed up and hugged the roof structure to give more storage space.

    Are you sure a flex has not pulled off somewhere?

  5. #18
    Join Date
    Jun 2004
    Posts
    43
    Simpleman,

    thanks for the response. I don't have the calcs.. this was 8 years ago but I was assured they were right (they were supposedly performed 3 times). I posted the equipment capacities but 125K BTU heat - 5 Ton cooling (2) 2.5 ton split units Teladyne Laars mincombo and minimates.


    I hear you on the "ho" problem but you can't put all the blame on the consumer. I agree the Ho mentality exists in new construction. I had many a low ball offer when I built my house but I didn't go with the low ball, I went with upper middle and based more on my comfort level with their "ability" to do a good job the first time. Your industry has to shoulder some blame as well. The service end of the business is not a Ho's market (at least not in my area). When you charge anywhere from $60-$100 per hour for service plus travel, I think I have the right to expect more than just a parts changer. If you were charging $30 an hour, OK... but thats never the case. I get charged top shelf dollar for bottom shelf guys that could not have an intellegent conversation about theory with a text book in their hand. The average homeowner may be fooled by that, (as long as the thing blows cold). But when guys like me try and try again to have pros solve problems that I conceed are not simple, and pros show up like Denny the Dunce... you guys will get black eyes every time! Especially at those rates.

    Sorry, just my opinion... I'm not happy getting a Yugo when I paid for a Porsche, and nobody would be.

  6. #19
    Join Date
    Jun 2004
    Posts
    43
    Sorry, missed two posts while typing my rant... please forgive my venting... I certianly meant no disrespect to the "true professionals" here. And if there are guys sitting around without work, It's not here. Getting guys out is like pulling teeth... theres too much work.

    That radiant shield sounds great but how do you get that in after the fact? The only ption I can think of at this point is a thermostatically controlled attick vent fan or fans. Is that done?


    And yes, I will take some measurements and repost.

    thanks to all for the help!

  7. #20
    Join Date
    Aug 2003
    Posts
    1,311
    other posts are covering this very well.

    alot of people wish every day to find a customer with your understanding. i'm sorry that you have had a bad run with "pros". i did'nt see mention of the mystery set point. but even though common in the industry to argue that 68 or whatever is not a/c but refrigeration, if the unit cannot maintain a certain temp capacity is first point of interest.

    another thing to look at is the design outdoor and indoor temps. do you know them. if operating outside design with aircooled condenser and increased heat gain, and indoor design temps were not selected by you, then that may be your problem.

  8. #21
    Join Date
    Sep 2002
    Posts
    3,708
    Thanks Jav for being cevil and yes I do blame other hvac contractor.

    Take your price of 60 to 100 dollars,as a hvac contractor
    that not alot of money to get a expert and the parts store
    into the driveway.

    So yes I do blame other hvac contractor that dont charge enough,to take care of there people,to offer the beenie to
    keep them,to give them the schooling they need to better
    there skill,at the same time being able to give the customer value for there dollar.

    I come here to this great site and see many of my fellow contractor that cant afford 250 year to support a site as
    this,where the expert come together and share there knowledge,and make it better for all.

    Why is that I ask?




  9. #22
    Join Date
    Jun 2004
    Posts
    43
    HVAC3901,

    I'm not sure what you mean by "mystery set point"? Are you asking my expectations of inside temperature or what we set our thermostats at? If so, I did post that we normally set the AC to 75 degrees during the summer... I think thats reasonable becuase most people I know go even lower.. like around 72 (which is too cold for me).


    Simpleman,

    when good people are offering to help me, I'd be a jerk if not civil and appreciative. And, I agree that 60-100 dollars to get an expert and a parts store into my driveway is darn cheap! The probelm is that its 60-100 PER HOUR PLUS TRAVEL to get a NON-EXPERT into my driveway. Thats not cheap or even reasonable.

    To give you an example. Just this last Tuesday, I spent $75 to get a guy out. At first glance, that seems cheap. Well I don't think so and here's why. It took 3 weeks to get this guy out. He could not give me a day (or a time) he would come but he was supposed to call the day before to confirm. He calls me at work out of the blue and tells me he'll be driving by my street in 15 minutes and if I can't meet him, he doesn't know when he can come back. Luckily, I work close enough where I was able rush out and meet him. He spent no more than 20 minutes on site, used only a set of guages and determined the system was too small... all before setting foot in the house. And when he heard that I would only consider a new system as a last resort and that I would need to be convinced that the problem was an undersized system with more than just "becuase this one isn't working", he was actually a little tiffed.. like i insulted his intellegence.

    So, 20 minutes of his time, no travel (he was passing by my street whether I could meet him or not), and nothing more than guages and his "proffesional opinion".... $75 bucks. That works out to $225 per hour and while cheap, I don't feel I got my monies worth.

    [Edited by jav on 06-17-2004 at 05:10 PM]

  10. #23
    Join Date
    Sep 2002
    Posts
    3,708
    You're a good man Jav,but that the problem I talking about,thats what I mean when I say it breed this kind of
    contractor,believe me I feel the sting from guys like this
    as well.


    See if you can get someone else out there,make sure you time it for the heat of the day.Ask him to show you the guages,if its a r22 system and the system not big enough
    to handle the load,both suction pressure and head pressure
    are going to be way above the norm.

    But again we can only guess as to what the problem is,we have no numbers.Do yourself a favor do a load calc and then
    you'll know.

    Good Luck!


  11. #24
    Join Date
    Feb 2004
    Location
    Midwest
    Posts
    9,932
    Hey jav, looks like you've gotten lots of good advice in my absence

    A good simple place to start would be taking regular temp measurements (we call these dry bulb) at the returns on the 2nd floor, and at the air handler. Also check the supply temps on the 2nd floor and at the air handler. I think someone touched on the importance of checking the supply heat gain, but not the return. Either one's a killer. I've also seen systems where 10 degrees was picked up in the return and another 10 in the supply on an attic unit. The result was room temp air coming out the supplies into the conditioned area.

    There are some *excellent* simple tutorials explaining superheat and subcooling in the "For your interest" forum here. They were authored by some of our best. We have many teachers here and tech reps.



  12. #25
    Join Date
    Jun 2004
    Posts
    43
    To all,

    I knew I was in the right place the moment I started reading posts here (well at least some of them.... theres always the "hey solve my problem and use your cyrstal ball cuase I ain't got clue" with the appropriate reply's that follow.

    I plan on visiting the local supply house and inquiring about wet bulb measurements or a sling psychrometer... if they aren't hundreds of dollars, I'll likely get something to enable me to provide you guys with some data to work with. I've already gotten enough info from you guys to suspect I'll find I'm loosing some ground in the attic duct work (likely both the supply and return). Next week, I'll post some supply/return air temp measurements at a couple of locations including right at the coil. I'll also get some line temps at the service fittings and if I can swing some guages, some pressures as well. I'll also record outside temps, relative humidity and t-stat info. I'm thinking some air flow measurements might be helpful but we haven't touched on that... is there a tool to determine that? I know what the what blower CFM spec is and what the pressure drop should be at that flow but I can't confirm any of it. I would think that the temp drop accross the coil will tell us if we have too much or too little flow??

    Anyway, I have some work to do and some data to collect..

    To all those helping, don't quit on me! I need you and I sincerely appreciate your reading this book and you great insight! Thank You!

    BTW - Offers still open to any of you pro's in the Masschusetts or rhode island area... I don't mind paying for this kind of experitse!

  13. #26
    Join Date
    Dec 2002
    Posts
    9,871
    Do a load calc. Big button at the top of screen.

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