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  1. #14
    Join Date
    Jun 2008
    Posts
    80
    It's been a while now since I had a heat load test done on my house and among other things they measured the living space volume (length, wide, height of each room), measured windows, took a stab at insulation values, estimated age of windows and doors and construction, ran it through some modelling software, and poof out came some heating and cooling capacity numbers.

    Can anyone give this poster some idea what should be measured on a heat load test, so that if someone comes over to do it the poster will have some idea if its being done right?

  2. #15
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,167
    Pretty much what you just described.

    And if you want it to be more aacurate yet, a blower door test to find out what your infiltration rate is. But you won't get that for free.
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  3. #16
    Join Date
    Jun 2008
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    8
    Quote Originally Posted by BigJon3475 View Post
    Maybe if you list a location.......some suggestions could be thrown out.
    Arizona. In Mesa, just outside of Phoenix.

  4. #17
    Join Date
    Apr 2007
    Posts
    6,285
    Againa thinking out loud.....


    Any chance you upgraded from R-22 to R410A?


    In MJ8 both Phoenixes have a cooling design temp of 107/108

    Not sure since I never see those but are those close numbers to where R410 starts to fall off quicker the R-22 falls off to some of the members in that area?

  5. #18
    Join Date
    Jun 2008
    Posts
    8
    Quote Originally Posted by BigJon3475 View Post
    Againa thinking out loud.....


    Any chance you upgraded from R-22 to R410A?


    In MJ8 both Phoenixes have a cooling design temp of 107/108

    Not sure since I never see those but are those close numbers to where R410 starts to fall off quicker the R-22 falls off to some of the members in that area?


    I have no idea.

  6. #19
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    you need to find a good HVAC contractor in your area

    then be specific about how cool you want your house on the hottest day

    your specific needs may require a 2 stage system that is oversized for "normal" conditions


    .

  7. #20
    Join Date
    Apr 2007
    Posts
    6,285
    Find out what refrigerant the system uses.

    Read this: http://www.eurocooling.com/articler410a.htm

  8. #21
    Join Date
    Jun 2008
    Posts
    8
    Quote Originally Posted by Airmechanical View Post
    you need to find a good HVAC contractor in your area

    then be specific about how cool you want your house on the hottest day

    your specific needs may require a 2 stage system that is oversized for "normal" conditions


    .


    I have had three companies come out and all three were mediocre at best. Hell the last guy that came out seemed like he was high or something. He just could not focus.

    If anyone can rec. a good company in the Phoenix area I would appreciate it.


    The only problem I have right now in regard to buying a whole new system is cost. Hence why I am hoping something can be done with the current one to help the situation.

  9. #22
    Join Date
    Jun 2008
    Posts
    8
    Quote Originally Posted by BigJon3475 View Post
    Find out what refrigerant the system uses.

    Read this: http://www.eurocooling.com/articler410a.htm

    Thanks for the link. What I gather from that article is 1, if they used R410A that the older air handler might not use that refrigerant as well, and 2 that R410A does not work as well as R22 when outside, ambient temps rise. Would these observations be correct?

  10. #23
    Join Date
    Apr 2007
    Posts
    6,285
    They are both pretty equal to about 110*.....after that the fall off of R-22 compared to R410 is more dramatic......it's just something that needs to be considered for total capacity in areas where design temps are so high. I wish I had a standard version of *F but if you do the conversion you will see the exact numbers.

    Yes basically you have it right. That's why I was curious about what refrigerant was being used or is in the new equipment.


    So both refrigerants fall off R410a falls off slightly faster.....in more mild climate they general work close to the same with the 410a have a slightly higher refrigerant capacity.

  11. #24
    Join Date
    Jun 2008
    Location
    va
    Posts
    800
    Correct me if I'm wrong, but if he used a 410 unit on a 22 air handler, it's not going to work right.....ever. You can't use 410 with a piston type coil if that's what's in there, if it is a TXV, it's designed for 22 not 410 and will probably choke the system down. Also if it's one of the old carrier air handlers with the all-aluminum evaporator coils, it will probably spring a leak quickly....Then again nobody could be that nuts and replace a 22 unit with a 410 and leave everything else, or could they?

  12. #25
    Join Date
    Jun 2008
    Posts
    80
    Talking to my neighbor these last few weeks. He works for Carrier and is upgrading his 10 SEER A/C to a Carrier 16 SEER HP, and I offered to help. While he bought his equipment at an unbelievable price, we were lamenting the high cost of copper because it would be really nice to reuse his tubing.

    According to him R-22 and R-410A refrigerants are not compatible so it is just safer to change out everything. He said you can flush the lines and then perform a test to determine if you've removed all the old, but that's usually only cost effective for commercial applications.

    From what I gather if you're changing to R-410A you need to change the unit, ID coil, lines and maybe the air handler and fan depending on the system.

    He also mentioned what you've all discussed here that R-410A is best used in moderate climates - whatever that means exactly.

  13. #26
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,167
    Quote Originally Posted by dac122 View Post

    According to him R-22 and R-410A refrigerants are not compatible so it is just safer to change out everything. He said you can flush the lines and then perform a test to determine if you've removed all the old, but that's usually only cost effective for commercial applications.
    He hasn't been to a Carrier class on R410A then.

    Its not the refrigerant compatibility, its the oil compatibility that could cause a problem.
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