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  1. #14
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,619
    we all know that installers cant read ( or wont )
    We really need change now

  2. #15
    Join Date
    Nov 2008
    Location
    DFW,TX
    Posts
    2,169
    what specific common issues are we talking about here?

    ive been installing Tappan the last two years and havent noticed any issues , YET.. Hopefully they wont start popping up but good to know what we should be looking for before this becomes an issue..

  3. #16
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Quote Originally Posted by acguytx View Post
    what specific common issues are we talking about here?

    ive been installing Tappan the last two years and havent noticed any issues , YET.. Hopefully they wont start popping up but good to know what we should be looking for before this becomes an issue..
    I think that if both the indoor and outdoor coils are micro channel, there are not any big issues, other than the system being less forgiving of being over charged.
    The real serious issues I've seen posted about were heat pump systems where one coil, especially the indoor coil, is micro channel, and the other is a standard tube and fin coil.
    When the Nordyne brands started giving out micro channel indoor coils as warranty replacements for failed tube and fin indoor coils is when I saw a lot of posts about problems with them.
    If more government is the answer, then it's a really stupid question.

  4. #17
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,024
    Quote Originally Posted by gravity View Post
    why do you need all that?

    Get a tee with depressor built into it. screw it to the suction service valve. screw the LPS into the tee side of the fitting. wire it in series with contactor coil and call it a day.
    Quote Originally Posted by mofotech View Post
    That's awesome! I didn't think of that! I actually thought about using a piercing valve but then remembered that you can't leave those permanent and will need a stem valve installed where the original pierced valve is installed. Awesome! Thanks for the suggestion!
    Potential for leaks... and it is outside the unit... looks hokey to me.

    OTOH: a drop of nylog on each set of threads... and the potential for a leak is seriously diminished.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  5. #18
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,024
    Quote Originally Posted by mark beiser View Post
    I think that if both the indoor and outdoor coils are micro channel, there are not any big issues, other than the system being less forgiving of being over charged.
    The real serious issues I've seen posted about were heat pump systems where one coil, especially the indoor coil, is micro channel, and the other is a standard tube and fin coil.
    When the Nordyne brands started giving out micro channel indoor coils as warranty replacements for failed tube and fin indoor coils is when I saw a lot of posts about problems with them.
    THX Mark... This makes sense.

    I had read a few of those threads about MC coil failures a while back... wrote it off to new technology rushed out the door without adequate R&D.

    If what you are saying is indeed the issue (time will tell); perhaps a negative view of MC coil equipment is a bit premature.

    I heard Rheem/Ruud will have MC coils in their split residential lines by the end of the summer... There is a product update meeting in a few weeks... hope to learn what is coming.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  6. #19
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Quote Originally Posted by ga-hvac-tech View Post
    THX Mark... This makes sense.
    Just to be clear, my post is what I understand from reading posts on this and other forums, not first hand experience.

    We've only installed two Nordyne(Tappan) MC coil systems, both indoor and outdoor coils are MC.
    Both have been within the last 2 months, and were straight AC, one with electric heat, and the other with an existing gas furnace.
    If more government is the answer, then it's a really stupid question.

  7. #20
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,060
    Nordyne HP outdoor coils are conventional. Our problem came when the indoor coil became MC. Had issues with high head in mild weather. 13 SEER used a piston, 14 and up used a TXV. Using TXV seemed to stop the issue so we used them even on 13 SEER. Nordyne's fix is a mild ambient fan cycle kit to keep the head down when heating on a mild day.

    We are finding that charging the all MC systems, in & out, sure is touchy and with the pressure put on the installers to be in & out, had some going back to remove charge happen.

  8. #21
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,024
    Hey BL...

    Do you charge the MC systems to SH/SC standards? Or do you carefully measure/calculate and weigh in? I can understand the TXV thing.

    The reason I am asking about MC coils is: I am not totally satisfied with the AlliedAir line (not the product, the distribution chain)... thinking of going back to Rheem/Ruud. When I heard they were going MC... it gave me pause. Trying to be sure I am not jumping out of the frying pan into the fire so to say...
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  9. #22
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,283
    all the coils I replaced were on systems that had txvs, or needed them. I also made sure the airflow was correct, since that can throw off charge.
    Col 3:23


    questions asked, answers received, ignorance abated

  10. #23
    Join Date
    Sep 2009
    Location
    Hampton, GA
    Posts
    530
    Quote Originally Posted by ga-hvac-tech View Post
    Hey BL...

    Do you charge the MC systems to SH/SC standards? Or do you carefully measure/calculate and weigh in? I can understand the TXV thing.

    The reason I am asking about MC coils is: I am not totally satisfied with the AlliedAir line (not the product, the distribution chain)... thinking of going back to Rheem/Ruud. When I heard they were going MC... it gave me pause. Trying to be sure I am not jumping out of the frying pan into the fire so to say...
    Hey BL , Whats best when adjusting these units for charge? I am using the chart to charge the units. Also will it happen that the subcool maybe slightly off but based on the chart , the charge is correct? I have one of the units the indoor coil has some slight water dripping off the coil from the middle and falling in the middle of the filter. I know that can be a indication of low charge or low airflow as the indoor coil maybe slightly icing up, although visual inspection didn't indicate that. But everything seem correctly setup. I am wondering the lack of load inside the building is causing the coil to be colder then it should. Indoor the building is a currently empty commercial building. Indoor is 73F. OD 76F. SH 10 SC 13. Suction Temp 50, Liquid Temp 79. Vsat 40 Lsat 92. Low side 120 High side 286. High side would jump up and down between 285-288 ( got measurements from sman3) I did a DeltaT and it came out 22 thats after I increased the airflow from 1405 to 1490, but I never really measured the cfm or Static Pressure , so it may not be totally accurate. (I will later on this week) I remember from class that a DeltaT 22 indicates not enough airflow perhaps. Air handler B6EMMX42K-B and outdoor unit JS4BD-042KA/B.

  11. #24
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,024
    Quote Originally Posted by ga-hvac-tech View Post
    Hey BL...

    Do you charge the MC systems to SH/SC standards? Or do you carefully measure/calculate and weigh in? I can understand the TXV thing.

    The reason I am asking about MC coils is: I am not totally satisfied with the AlliedAir line (not the product, the distribution chain)... thinking of going back to Rheem/Ruud. When I heard they were going MC... it gave me pause. Trying to be sure I am not jumping out of the frying pan into the fire so to say...
    Follow-up to my post:

    Seems the sales rep at the Ruud shop was wrong... Rheem/Ruud will NOT replace their entire evap coil line with MC coils... rather tub & fin all aluminum coils (same 'N' configuration, with CO tubes for brazing). They should get here later in the Summer or fall, depending on how quickly the existing stock of CO tube/Al fin coils is sold out.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  12. #25
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,060
    Use whatever chart is appropriate. Subcool on TXV inside, pressures on piston coils. I noticed some of the subcool targets are lower than before. Just gotta go real slowly!

    GA, what about MC outdoors on Rheem?

  13. #26
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,024
    Quote Originally Posted by BaldLoonie View Post
    Use whatever chart is appropriate. Subcool on TXV inside, pressures on piston coils. I noticed some of the subcool targets are lower than before. Just gotta go real slowly!

    GA, what about MC outdoors on Rheem?
    So far all I can get out of the tech folks (both Rheem and Ruud, different dist) is many of the package units use MC coils, and some outdoor units use them... they are vague on which outdoor units.
    I did get out of the tech guy at Rheem; the MC coils are being manufactured by Delphi (division of General Motors).

    I did get a commitment on the new aluminum indoor coils... they are tube/fin, all aluminum, with CO stubs for brazing... and possibly bolt in TXV's. I was told the reason for going all aluminum was formicary corrosion. Asked about outdoor all aluminum (tube/fin) coils... guy got vague and said the issue was formicary corrosion... so why change the outdoor units. Then in the very next breath he said the indoor units would be waaaay cheaper to make all aluminum. I did not poke at him about why not the outdoor units also...

    MeThinks they may be doing some testing... and when they decide... we will find out. Just my $0.02...

    They did say the entire furnace line was being re-designed; new condensing furnaces will be here by late summer or fall depending on inventory. Main feature of the new 90+ units is the upflow will work left or right also... I guess movable DIM motor and/or various drain options (IMO that was overdue). The new 80% have cut-outs on the sides for venting... not sure I like that... they will be more noisy unless they have a 'firebox' inside. I saw some pics of them... they look like appliances... wonder what they are thinking. I like the way they look now.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

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