Page 3 of 3 FirstFirst 123
Results 27 to 32 of 32

Thread: Lineset Size

  1. #27
    Join Date
    Jul 2005
    Posts
    643
    Originally posted by ikey
    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.
    Undersizing the suction line should only be done as a velocity riser if the compressor is above the evaporator to assist in oil return, and only the riser is undersized. A system with an undersized suction line will probably seem like it's working ok but really not. Suction pressure will be low due to the line's lack of ability to carry enough refrigerant back to the compressor. Low suction results in colder evap temps and a cool but clamy house, not to mention the higher potential of ice-ups.

  2. #28
    Join Date
    Dec 2005
    Posts
    894
    Originally posted by matt8085
    Originally posted by ikey
    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.
    Undersizing the suction line should only be done as a velocity riser if the compressor is above the evaporator to assist in oil return, and only the riser is undersized. A system with an undersized suction line will probably seem like it's working ok but really not. Suction pressure will be low due to the line's lack of ability to carry enough refrigerant back to the compressor. Low suction results in colder evap temps and a cool but clamy house, not to mention the higher potential of ice-ups.
    Uh, ok. And? No one is talking risers and location of the compressor. Ruud, lineset sizing, correlates different line sizes to difference in capacity, not seer. Capacity can be based on line set size and length. Ari does not configure systems seer ratings on line set size. Of course their ratings are in a lab. Your point?

  3. #29
    Join Date
    Jul 2005
    Posts
    643
    The point is a undersized suction will absolutely affect efficeincy. How about when the coil has a nice layer of frost on it due to the lower evap temp, how efficient is it then? Sooooo, what is the result in lowering the capacity of a system by undersizing the suction line? It's a drop in efficiency. My point was to simply point out that the only time it should be undersized is in a vertical riser application. Maybe you knew that but I bet there are guys on here that didn't.

  4. #30
    Join Date
    Dec 2005
    Posts
    894
    Originally posted by matt8085
    The point is a undersized suction will absolutely affect efficeincy. How about when the coil has a nice layer of frost on it due to the lower evap temp, how efficient is it then? Sooooo, what is the result in lowering the capacity of a system by undersizing the suction line? It's a drop in efficiency. My point was to simply point out that the only time it should be undersized is in a vertical riser application. Maybe you knew that but I bet there are guys on here that didn't.
    Your right, of course that would affect efficiency, but that is an extreme case. and rare, hence the discussion about old duct systems on new 13 seer systems. Not any concerns of line set size. Basically, without any extreme undersizing, lines set size has more of a reflection on capacity, not efficiency.

  5. #31
    Join Date
    Jul 2005
    Posts
    643
    Originally posted by ikey
    Originally posted by matt8085
    The point is a undersized suction will absolutely affect efficeincy. How about when the coil has a nice layer of frost on it due to the lower evap temp, how efficient is it then? Sooooo, what is the result in lowering the capacity of a system by undersizing the suction line? It's a drop in efficiency. My point was to simply point out that the only time it should be undersized is in a vertical riser application. Maybe you knew that but I bet there are guys on here that didn't.
    Your right, of course that would affect efficiency, but that is an extreme case. and rare, hence the discussion about old duct systems on new 13 seer systems. Not any concerns of line set size. Basically, without any extreme undersizing, lines set size has more of a reflection on capacity, not efficiency.
    I agree totally. The system is only as big as the amount of refrigerant it can move in volume, regaurdless of the size of the compressor. Unfortunately too many contractors out there don't even pay attention to line sizing and think the outlet size on the equipment is the right size to run. The most common thing I see is a super long 7/8" line on a 5 ton system. Customer wants to know why it feels damp in the house, novice tech can't figure out why he can't the suction pressure above 50 psi.

  6. #32
    Originally posted by matt8085
    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
    Thanks for the support Boss!.


    Cheers

Page 3 of 3 FirstFirst 123

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event