Too complicated? - Page 2
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  1. #14
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    Nov 2000
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    Eastern PA
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    Quote Originally Posted by 21degrees View Post
    Tell him he is full of something and its not R410A. I have Installed for years r410a and no problems for me. Tell him to get someone compitent cause he can't even make a face like a A/C tech.
    You do realize that you are judging and condemning an HVAC professional on the say so of a somewhat incoherret HO post, don't you?

    Have you never had a disgruntled customer? Have you never had a customer who wants to second guess you? How would you feel if other HVAC pros talked about you like that based on information given over the Internet by a HO?
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  2. #15
    Join Date
    Apr 2008
    Location
    Alberta Canada
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    2,246
    No I think this HO is telling truth and I will stand by everything I said.

  3. #16
    Join Date
    Aug 2008
    Posts
    4
    Thanks for all the responses to my question. After spending hours on this forum and other sites I can make my best (uneducated) guess at what's going on.
    We had been running the system all summer and it was keeping our split-level house nice and cool even on the hotter days. Some of the downstairs vents had been closed, hoping to force more cold air to the upstairs vents. Had been working well all summer. We went away the last week in july, set the thermostat to 82 while we were gone. On returning we went back to our original programmed settings (76) but the system was never able to recover, started icing up. That's when we had the tech come out and got the diagnosis of an incorrect valve.
    Based on info I got from this site and others I decided to maximize airflow by opening ALL the returns and bringing the indoor temp down one degree at a time, also running dehumidifiers in a couple of rooms. Over the last 16 hours have managed to get the temp to hold at 78 and no icing; don't want to get greedy yet but may try to get to 76 so the upstairs is comfortable.
    I suspect (and hope) that iraqveteran and others here are right on target about airflow. Is it accepted knowledge in the industry that a house must be cooled slowly like I'm trying to do? Operator error, possible poor duct design and unfavorable conditions are probably all factors here. Still, the tech knew we were away for a week and seems like he may have figured this out. Maybe the TXV kit is still worth doing, I just don't have $900 dollars right now.

  4. #17
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,615
    I can shut my A/C off all day. Let the house temp rise to 80plus, turn the A/C on, and let it run until my place gets down to 70, and not freeze the coil.
    Thats the way it should operate. Your system may have always been low on return and or supply. And your shutting down some supplies just made it worst.

    I don't know how they can determine whats wrong, and not know that it had low air flow.
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  5. #18
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
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    11,273
    Quote Originally Posted by beenthere View Post
    I don't know how they can determine whats wrong, and not know that it had low air flow.
    Because many techs don't know how to measure airflow, so they come up with conjecture, hoping it will hit the target so they can move onto the next call.

    I've been there, done that. My old boss would hammer me about always checking airflow before adjusting charge on a frozen coil call. It finally sunk in that you can't just gas your way out of problems. You have to find the root cause and eliminate it.

  6. #19
    Join Date
    Apr 2008
    Location
    Alberta Canada
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    2,246
    How hard can it be to measure air flow. I bought a fluke 922 pretty easy. But if you check SH/SC and IWB,IDB and LDB and your in your range whats the problem.

  7. #20
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    Jan 2004
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    Lancaster PA
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    Quote Originally Posted by 21degrees View Post
    How hard can it be to measure air flow. I bought a fluke 922 pretty easy. But if you check SH/SC and IWB,IDB and LDB and your in your range whats the problem.
    I'm not saying yoou need to know down to the CFM what the air flow is.

    But when you say with in your range.
    What is with in range.

    How grey, is your grey area for air flow.

    If 22° coil delta is your normal cut off. Is there a time you decide 23 is close enough.
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  8. #21
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    Apr 2008
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    TEXAS
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    Quote Originally Posted by comfortdoc View Post
    Sounds like someone tried to compensate for low air flow by overcharging the system. I suggest you find a competent tech in your area evaluate this system before spending much more money on what sound like guesses.
    and make sure he checks it with all the return and supply vents open, clean new filter etc...
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  9. #22
    Join Date
    Nov 2000
    Location
    Eastern PA
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    So, not intending to cause any problems, the HO altered the amount of air in the system and then added a load by allowing the home to get hot and humid.

    When attempting to bring the temperature down, the HO has now created a situation where not only is there less air, but there is more humidity. Had the system continued to operate without letting the temperature of the home rise, there would not have been enough load/humidity for the lower airflow system to have a problem with.

    Now, along comes a tech who is assuming (yes, this is always wrong of us) that the conditions of the home and system are the same, so he/she goes looking for a mechanical reason for the problems.

    Coils freeze up for one of two reasons; low airflow and/or low refrigerant. Since the system did not have an airflow issue before and hopefully the technician checked for dirty filter, blower etc; if there were none of these indications of lessening of the air, then the txv was the logical culprit that would be not allowing enough refrigerant into the coil which would give the results of a low refrigerant charge.

    Yes, other tests could have eliminated the condemnation of the txv, but there is no reason to be insulting this technician the way he/she is being insulted.
    Government is a disease...
    ...masquerading as its own cure…
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  10. #23
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    Apr 2008
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    Alberta Canada
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    Beenthere I use a Slide rule

    Quote Originally Posted by beenthere View Post
    I'm not saying yoou need to know down to the CFM what the air flow is. But when you say with in your range.
    What is with in range. How grey, is your grey area for air flow.
    If 22° coil delta is your normal cut off. Is there a time you decide 23 is close enough.

    As long as you are within 3*F not a problem if you are 3*F or lower than set point you have to increase evaporator fan speed if you are 3*F higher then set point you have to slow speed down.

  11. #24
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    Jan 2004
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    Lancaster PA
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    I have a slide chart also. It allows 5°.
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  12. #25
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    Apr 2008
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    Alberta Canada
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    I actually have arround 6 different slide rulers, but this one seems to be the best one. I keep looking for newones. They all say allow +or- 3*F

  13. #26
    Join Date
    Feb 2008
    Location
    Waffleville
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    i have a slide too...

    wait.

    wait.

    wait.

    i cannot find the darn thing!!! maybe i should have 20 of them laying around too....
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