Lineset Size - Page 2
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Thread: Lineset Size

  1. #14
    Join Date
    Apr 2005
    Location
    new jersey
    Posts
    752
    they need to finish what they started correctly.tell them if rain/mold gets in that they can be held liable.
    good luck

  2. #15
    Thanks for the replies. I used your responses as ammunition and raised hell. He now has indicated that he will have a new flashing installed when he runs the new lineset.

    There was not another line ran for the combustion air. The utility closet is vented and an elbow was installed on top of the furnace at the combustion air inlet.

    It is really weird that he was reluctant to run a 1 1/8 inch lineset and replace the roof exhaust pipe boot. The rest of the work looks top notch. I guess that he just felt that a 7/8 inch line would be adequate based on his past experience.

  3. #16
    Join Date
    Sep 2004
    Location
    Memphis
    Posts
    2,502
    Originally posted by techgenius
    the 3/8" insulation on the Suction line is a bit weak and should be at least 1/2". The liquid line should be insulated as well if the lines are running through an attic like you had mentioned, this will keep your subcooling up and provide maximum efficiency. If you don't insulate the lines like I suggest then you are probably going to have problems in the future.

    Cheers
    I have never seen a liquid line insulated. That seems like overkill.
    Life is like a jar of jalapenos. What you do today might burn your ass tomorrow.

  4. #17
    Originally posted by hvac hero
    Originally posted by techgenius
    the 3/8" insulation on the Suction line is a bit weak and should be at least 1/2". The liquid line should be insulated as well if the lines are running through an attic like you had mentioned, this will keep your subcooling up and provide maximum efficiency. If you don't insulate the lines like I suggest then you are probably going to have problems in the future.

    Cheers
    I have never seen a liquid line insulated. That seems like overkill.
    Could anyone else comment on this?

  5. #18
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    I've seen pvc drain line insulated in Fl. Overkill? Probably,but engineers love overkill. and if that insulation saves you that 1/8 of a seer....you decide.
    If everything was always done "by the book"....the book would never change.

  6. #19
    Originally posted by mrgoodman
    Originally posted by hvac hero
    Originally posted by techgenius
    the 3/8" insulation on the Suction line is a bit weak and should be at least 1/2". The liquid line should be insulated as well if the lines are running through an attic like you had mentioned, this will keep your subcooling up and provide maximum efficiency. If you don't insulate the lines like I suggest then you are probably going to have problems in the future.

    Cheers
    I have never seen a liquid line insulated. That seems like overkill.
    Could anyone else comment on this?
    Ask your manufacturer about it. If your condensing temp is 110F and you get subcooling out of a 85F ambient, what do you think is gonna happen to the subcooled liquid if it is run through an attic at 140-160F. Im not saying to insulate it if you are 5ft in the attic but if you run it 40ft + well it should be considered and most manufacturers recommend it. Dont believe me look at the piping guidlines from your manufacturer.

    Cheers

  7. #20
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,567
    the liquid is traveling at 800 fpm, how much temp can it pick up. I would guess you may loose a few degrees of sub-cooling which is not too bad. I have never insulated one, but maybe i will use my thermometer one day to see if i pick up any heat !

  8. #21
    Join Date
    Jul 2000
    Location
    Louisiana , USA
    Posts
    3,280
    I have never seen a liquid line insulated. That seems like overkill. [/B][/QUOTE]


    This is Turtle.

    I think he is talking about 3/8" thick insulation on the suction line or does he need 1/2" thick insulation on the suction line.

    TURTLE

  9. #22
    Join Date
    Jun 2001
    Location
    San Diego, CA
    Posts
    1,149
    Your contractor sounds like a tailgate charlie - but if he's accomodating your requests give him an attaboy. I know of several that unless exactly specified, you get what you get. The 7/8 line is not a huge deal and the difference in real world vs. a 1 1/8 will be hardly noticable - but it's in the book so it should get done.

    The 3/8 insulation is what standardly comes applied to roll form tubing and changing it to 1/2 will create some work for him. The 3/8 will do fine if it's not tore up during the install as it only needs to keep the pipe from sweating. A marginal measure of efficiency will be gained from upsizing the insulation and even in insulating the liquid line. Were I the contractor, I would look at these as extras. Guess it depends on what you've agreed to.

  10. #23
    Join Date
    Nov 2002
    Location
    cincinnati ohio
    Posts
    504

    lineset

    I looked at the specs on 1 1/8 verses 7/8 copper and the differece is next to nothing . you loose a couple hundred btu's . The key is the distance , Over 50 foot it starts dropping . Under 50 ft theres no difference . This was on a trane chart . Most the piping once it hits the service valves from 7/8 to 3/4 . So im sure its a volume issue when the linesets over 50 ft . bh

  11. #24
    Originally posted by Freezeking2000
    the liquid is traveling at 800 fpm, how much temp can it pick up. I would guess you may loose a few degrees of sub-cooling which is not too bad. I have never insulated one, but maybe i will use my thermometer one day to see if i pick up any heat !
    Dewly noted however if you plot information on a PH diagram to show the efficiency of R22 and the effects of losing subcooling it is marginal but if you do the exact same design with 410a and start reducing the subcooling. WOW! it makes a huge diff. on the efficiency. Try it. You seem like a smart lad giving it that you know how fast the liquid is traveling in the liquid line, you should be able to plot this info on a Ph Diagram.


    Cheers

  12. #25
    Join Date
    Jul 2005
    Posts
    648
    Liquid line should ALWAYS be insulated anywhere where it could potentially pick up heat. Should deffinitely be insulated in an attic. That's refrigeration 101

  13. #26
    Join Date
    Dec 2005
    Posts
    894
    Originally posted by smokin68
    If you don't install what is spec'ed, you won't get the spec'd seer,14 in this case. Use the proper size.
    I was told that a smaller suction will not affect efficiency, only capacity. Also had a major co. down here that was a Lennox new construction and almost lost their dealership because of installing 1/2 in liquid lines in many homes. Killed many compressors. I haven't seen a pub yet that recommends 1/2 liquid on anything less than 5 tons.

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