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  1. #1
    Join Date
    Aug 2008
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    San Clemente, CA
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    Lennox 4 ton horizontal two-zone system

    Left side of attic access cut-in new 20x30 bar type return air grill and abandon original grill over access, plated off old grill with sheet metal plate in attic to make air tight. Owner may remove and patch it some day.


    View looking into attic from access.


    View of horizontal installation on 6" high pitched horizontal furnace stands.


    View of condensate plumbing. Insulated J-Trap (so it does not sweat). Notice the custom height PVC/Plumbers tape supports.


    View of condensate drain drywell. Used Hilti 1-1/8" masonry drill bit to drill PVC pipe through a 8" deep concrete stem wall.


    Outdoor unit with (4) two-inch ABS couplings used as risers to elevate the unit three-inches above the hard scape and secured with hold downs (both of these are code around here). Fused electrical disconnect.


    Pitched horizontal furnace stands:

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  3. #2
    Join Date
    Jan 2011
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    I typically shoot for a level furnace. Am I doing it wrong? I don't put furnaces in attics so I sure don't envy you!

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  5. #3
    Join Date
    Aug 2008
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    Thread Starter
    We pitch fau forward so that horizontal drain pan on cooling coil is pitched forward. Instructions state you can set fau level or pitched. This is true for 90%+ fau's too. Talking with Lennox engineers they actually like that the 90%+ fau is pitched forward as it helps to evacuate water out of the heat exhanger. 80% fau is not affected, we do it for positive condensate evacuation from the evap cooling coil.

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  7. #4
    Join Date
    May 2006
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    The Condenser looks like it is going to be a bit tight to service it on the left side or do you have more room then the picture shows

  8. #5
    Join Date
    Apr 2010
    Location
    Austin,Texas
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    I've used pvc as a pipe support before, with the strap over the top, but your way is better. I'll be doing that from now on.


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  10. #6
    Join Date
    Oct 2010
    Location
    The very humid south
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    I really do not like to be critical of other peoples work. I'd much rather encourage someone than criticize. However, could someone please explain to me the theory behind installing a top access coil in a position that you CANNOT access it from the top???

  11. #7
    Join Date
    Aug 2008
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    Thread Starter
    The coil manufacturer ADP does not call out any requirements for service access. In attics, space is limited.

  12. #8
    Join Date
    Mar 2007
    Location
    Madison, Wisconsin
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    Looks nice to me. I also learned something with that little PVC/strap trick.
    I r the king of the world!...or at least I get to stand on the roof and look down on the rest of yall

  13. #9
    Join Date
    Jun 2012
    Location
    Northern NV
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    Secondary drain pan under condensing furnace is mandatory code here for an attic install. I do like the plywood floor.

  14. #10
    Join Date
    Sep 2005
    Location
    Atlanta GA area
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    The 'top access' coil, if I am seeing this correctly, is a 'dedicated horizontal' coil... I use those exclusively on all horizontal applications... they do not sling water towards the intake like turning a multi-position coil on its side does.

    They do come with the access cover on top, and the lineset fittings on top.

    We use media filters on all our installs (other than slumlords), so cleaning the coil is all but a non-existent issue (and the systems last longer).

    I agree with tilting the system towards the front... do that on all installs (horizontal and vertical)... allows for better coil (and condensing furnaces) to drain thoroughly at the end of the cycle.

    I do have some concern as to the location of the outdoor unit... however there are urban installs where the best locations and clearances are not available. IMO still beats putting the outdoor unit on the roof!

    Nice install... like the condensate bucket... avoids a puddle and mosquito breading district...
    Ga-HVAC-tech

    Your comfort, Your way, Everyday!

  15. #11
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    Aug 2008
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    Thread Starter
    Thanks ga-hvac-tech. The condensate bucket is a section of 6" PVC pipe. We bought a length of pipe and chopped it up into 8" long sections and store them in a box marked "Dry Wells". On the job we dig out the hole, drop the sleeve and fill it with 3/4" rock. Even had a inspector one time have us install a pull stick marked at 18" so he could pull it to see that we dug it down 18". Funny how that city has the sandiest soil around (good drainage) and they make you do that. I thought that was taking it to the extreme.

  16. #12
    Join Date
    Mar 2013
    Location
    Billington Heights, NY
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    Being that close to the ceiling it might not hurt it to turn the grates upside down, so that they cant been seen into from below. Just an aesthetic thing.
    Experience - knowing when to get the hell out of the way and plug your ears. "Don't be a sissy. Turn it on!"
    Poodle Head Mikey - "the world is well populated with the unknowing and the uncaring and the stupid."

  17. #13
    Join Date
    Aug 2008
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    Thread Starter
    I was thinking of telling my guys the same thing. The other thing we do is set the fan off time to at least 120 secs sometimes 180 because this return air is warmer than at the floor and it takes longer to cool the furnace down. Factory sets this Lennox SL280UH090XV48B furnace at 90 secs. This would possibly trip the blower limit during off cycle (I have seen them do this).

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