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  1. #1
    Join Date
    Jun 2003
    Posts
    11

    Service Call on an Engineer's House

    I went on a service call last week, in a nicer gated community home in my area. The homeowner informed me that they had 3-4 other techs out over the years, and they still felt their upstairs AC isn't working properly.

    When I arrived I found the unit to be low on charge, and a schrader cap was missing. I began to charge the unit up and started to end up with 60psi on the low and 240 on the high. 15 year old unit, 85 ambient 76 in the house, 4 ton.

    I suspected a airflow problem, and when I went up into the attic, I found that some knucklehead had installed a 4 ton upflow furnace and coil, but didn't have room for a plenum so they simple cut 4 ducts off the evaporator coil casing itself. (Even I didn't notice it at first, because its not something I have ever found missing before)

    I tried to find some research online to help explain to this gentlman why his system will not run properly until this problem is addressed, also how its costing him alot more in electricy and shorting the life span of his unit. Any advice would be appreciated.

    Thanks

    Dean
    Ace Air

  2. #2
    Join Date
    Jul 2007
    Location
    Delaware
    Posts
    3,824
    He must actually be an engineer in the truest form of the word, as in railroad tracks.
    Always here

  3. #3
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,347
    Quote Originally Posted by energy star View Post
    He must actually be an engineer in the truest form of the word, as in railroad tracks.
    At the very least, sounds like somebody's understanding of air distribution went off the rails.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  4. #4
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    You may have to draw him a diagram with mass balances pressures, air flow rats, heat loading, and plenty of charts and spreadsheets... then he might understand. Try ot explain something to some eingineers in plain english and they just smile and knod and 2 days later ask you to explain it all over again.

    Some engineers don't understand things verbally and don't do field work. It must be shown to them on paper.

  5. #5
    Join Date
    Jul 2007
    Location
    Delaware
    Posts
    3,824
    Yes, he needs to be put back on track.

    As an engineer he's blowing a lot of steam.
    Always here

  6. #6
    Join Date
    May 2009
    Location
    Central Florida
    Posts
    65
    Quote Originally Posted by mrbogie View Post
    I tried to find some research online to help explain to this gentlman why his system will not run properly until this problem is addressed, also how its costing him alot more in electricy and shorting the life span of his unit. Any advice would be appreciated.
    The air handler manuf. should be able to provide you with all the material you need to show him. Now whether he does something about it.

  7. #7
    Join Date
    Mar 2009
    Location
    Several Miles from Sane
    Posts
    1,458
    Quote Originally Posted by energy star View Post
    Yes, he needs to be put back on track.

    As an engineer he's blowing a lot of steam.
    Don't tell us he lives at 2 2 Twain by chance.

    My symathies in the attempt to explain it to the homeowner. Maybe show him a simplified H-Pattern drawing with lots of patienence.
    If sense were so common everyone would have it !

    All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!

  8. #8
    Join Date
    Nov 2008
    Location
    Meriden, Kansas
    Posts
    435
    For an engineer type I would show him the specs that specify maximum static pressure for his blower and then hook up a manometer and show him his pressure.
    Anything I say here is only my opinion. Even if you understood what I said.... What I said may not even be what I meant.

  9. #9
    Join Date
    Jul 2007
    Location
    Chicago IL
    Posts
    167
    did you figure out how to fix the plenum problem?

  10. #10
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,561
    My advice is to explain it to him as best as you can. Write it on your service ticket in details. Collect a check for your time and leave. If he wants it fixed, he'll call you, if not. Move on. I had an engineer last year that we installed a 9000 BTU or so window unit in his little workshop. Probably around 200-300 cfm. He had a shop air cleaner which ran at 1200 cfm. He had it hooked up to the return of his window unit to clean the air before it entered the unit and couldn't figure out why it didn't work. My best explanation to him was trying to fill a bucket with a fire hose. He still couldn't understand the problem. I simply wrote it down and left. It's his problem now.
    I like DIY'ers. They pay better to fix.

  11. #11
    Join Date
    Aug 2008
    Posts
    56
    Firstly, congratulations for quickly identifying what the previous 3 to 4 techs over the years apparently weren’t able to identify.

    Not sure what the concern is all about when it comes to explaining the problem to the Engineer/ client. Simply and confidently tell him that the thing-a-ma-jigs are connected way too close to the what-cha-ma-call-it.

  12. #12
    Join Date
    Jan 2009
    Location
    Indiana
    Posts
    3,228
    My father is an Engineer....i can speak it fluently..but at times have trouble with standard English

  13. #13
    Join Date
    May 2009
    Posts
    20
    Quote Originally Posted by mrbogie View Post
    15 year old unit,


    also how its costing him alot more in electricy and shorting the life span of his unit.

    15 year old unit?
    Good luck to you trying to explain to him how it is "shorting the life span of the unit"!!

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