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  1. #1
    Join Date
    Oct 2007
    Location
    Chester County, Pennsylvania
    Posts
    15

    Am I being given accurate information?

    I am new to this forum and to heat pump purchasing. Here is my situation.

    I live in a condominium in Southeast Pennsylvania. My residential location is entirely on the second floor of a building. My neighbors live on the first floor. The outdoor unit is on the ground outside. The lines run through the walls up to the second floor. My ducts are in the attic. The flow of air inside is from the top of the room to the bottom of the room.

    Here is what I have been told by prospective installers, all of whom are NATE certified. What is accurate on this list?


    1. Since the ducts are in my attic and the air flow in the interior runs from the top of the room to the bottom of the room, I must add 15% to the manual J load calculation. Even though your neighbors, in comparably sized housing, use 2 ton units, you need a 2.5 ton unit.

    2. Again, as a result of the top to bottom air flow, a variable speed air handler is of no value to you. You should purchase only a standard air handler.

    3. Over the course of a year, your maximum monthly electric bill is only $100 more than your minimum monthly electric bill. The cost savings from a replacement heat pump will be minimal. Limit yourself to a 13 SEER unit with a standard air handler. There is no cost benefit in a higher efficiency system.

    4. You can use a unit rated for 3/8 inch lines with your current 1/4 inch lines. All you need is a TXV.

    5. You can use a new R-410 system with your current R-22 lines. All you need to do is to let us flush the current lines with RX-11.

    6. You currently have a condensation pump. Condensation is not being currently removed by any gravity based system. You should allow us to tap into your current tubing and divert the condensation into new 3/8 inch tubing which we will route into your laundry room and then make use of the moisture disposal system used by your washing machine. That will preserve the life of your current lines.

    Thank you for your time.

  2. #2
    Join Date
    Jun 2007
    Location
    Metro St. Louis
    Posts
    181
    First of all, I am NOT a pro, so my thoughts are only worth a couple of pennies!

    #1 - If the ducts are running thru the attic, you have to consider the impact of the losses inherent with attic temperatures. These losses can be mitigated by ensuring that the connections are airtight and insulated, but there will be losses.

    #2 - I don't get this at all. Doesn't seem right.

    #3 - Dunno your climate and sizing. How much do your bills differ now? You would need to figure out how much you spend over a summer to cool your house. You should then be able to determine any savings you would get from going to a higher seer. There's a bigger difference between 10 SEER and 13 SEER (30%) than there is between 13 SEER and 16 SEER (23%). As for in heating mode, look at the HSPF values. Most HSPF values are 8-9, which could be significantly higher than your current system.

    #6 - BS. Your "lines" are plastic (clear plastic or PVC). I doubt they'd degrade in anyone's lifetime sufficiently to be of a concern. They might plug up, but that's a different matter.

  3. #3
    Join Date
    Aug 2004
    Location
    Kentucky, Michigan, Ohio, Arizona, Colorado, Nevada, and Califormia
    Posts
    318
    A txv doesn't compensate for line size. BS. Variable speed is worth it IMO. You benefit from reduced energy consumption, better summer dehumidification, and less noise. RX-11 is a good product, but some manufacturers will void your warranty if the lines are not replaced when converting to 410. Also, most 410A systems require an increase of line size, so if you require 3/8-7/8, your current line sizes of 1/4-?? will not support your new system, RX-11 or not.
    "Surprised ?! If I woke up tomorrow with my head sewn to the carpet, I wouldn't be more surprised."
    Clark Griswold

  4. #4
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    there isn"t a local crack house is there? What brand equipment are you considering, model #'s. Most brand heat pumps are not approved for 1/4 inch liquid.

  5. #5
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by StuSuss View Post
    1. Since the ducts are in my attic and the air flow in the interior runs from the top of the room to the bottom of the room, I must add 15% to the manual J load calculation. Even though your neighbors, in comparably sized housing, use 2 ton units, you need a 2.5 ton unit.
    Manual J takes into account the location of the ductwork, if the correct data is input to begin with, no extra needs to be added on.
    Manual J has a roughly 20% fudge factor built into it already.

    2. Again, as a result of the top to bottom air flow, a variable speed air handler is of no value to you. You should purchase only a standard air handler.
    Ridiculous statement.

    3. Over the course of a year, your maximum monthly electric bill is only $100 more than your minimum monthly electric bill. The cost savings from a replacement heat pump will be minimal. Limit yourself to a 13 SEER unit with a standard air handler. There is no cost benefit in a higher efficiency system.
    The "sweet spot" for cost vs benefit with most manufacturers equipment is usually a "13 SEER" outdoor unit matched with an air handler that has a variable speed blower and TXV equipped coil. Usually it results in around a 14 SEER system.
    Spending more on a higher end higher SEER outdoor unit will save a little more, but usually the main benefits are things like less noise from the outdoor unit, multiple stages, sometimes better warranties, etc.

    4. You can use a unit rated for 3/8 inch lines with your current 1/4 inch lines. All you need is a TXV.
    It depends on the manufacturer, size of the system, length and lift of the line. Some manufacturers are OK with a 1/4" liquid line on up to 2.5 ton R-410a equipment.

    5. You can use a new R-410 system with your current R-22 lines. All you need to do is to let us flush the current lines with RX-11.
    If they can be reasonably replaced, I would recommend doing so. If not, as is the case with many condos, the Rx-11 flush works great.

    6. You currently have a condensation pump. Condensation is not being currently removed by any gravity based system. You should allow us to tap into your current tubing and divert the condensation into new 3/8 inch tubing which we will route into your laundry room and then make use of the moisture disposal system used by your washing machine. That will preserve the life of your current lines.
    Hopefully they are not wanting to use 3/8" tubing for a gravity driven condensate drain...
    It is a violation of the International Mechanical Code, and other codes, to reduce the condensate drain to a smaller size than the outlet of the drain pan. Every residential system I know of has a 3/4" outlet, so the pipe has to be 3/4" or larger.
    I'm not a fan of condensate pumps myself, but I don't think it is worth spending a whole lot on retrofitting a gravity drain.
    You need good condensate safety either way.
    If more government is the answer, then it's a really stupid question.

  6. #6
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by lra View Post
    Also, most 410A systems require an increase of line size,
    Actually, it is reverse, R-410A systems use smaller lines than R-22 systems.

    I love it because it means we only have to screw with running 1 1/8 copper for 5 ton systems on very long lineset applications, and 1 3/8 is a thing of the past for residential systems.
    If more government is the answer, then it's a really stupid question.

  7. #7
    Join Date
    Aug 2003
    Location
    Lincoln, Nebraska
    Posts
    1,051
    Mark has great advise as always. I would take it and get other estimates. A nate certified person dosn't mean they know more than non nate certified. Sounds like these people don't know very much about upgraded systems and just want to put in a simple system that they understand. Find someone that knows and works on upgraded systems and get more accurate ideas.

    We have some places in town that give the same info that you are getting. Its because there people don't work on or sell upgraded systems.

    A word of advise on using your old lineset over. Make sure it was soldered with somthing that can handle 410 pressures. We have run into some old systems that were soft soldered and we had to go back with a r-22 system.

    Good luck
    Its a good Life!

  8. #8
    Join Date
    Oct 2007
    Location
    Chester County, Pennsylvania
    Posts
    15
    Thank you Mr. Beiser and others for your helpful advice. It does concern me when even the professionals on this board provide contradictory information on whether 410A systems require an increase of line size (Ira) or use smaller lines (Mark Beiser).

    Here is what I am thinking now. Correct me if I am badly mistaken.

    1. My current builders-installed heat pump is 15 years old. It is on borrowed time and will need to be replaced soon. I might as well replace it now, before it dies in the middle of a Pennsylvania winter. However, since my current energy use is not high, the savings from a more efficient unit will be minimal. I will never recoup the cost of this purchase with utility bill savings.

    2. Given what I just said, I should focus on minimizing the cost based on what Mr. Beiser describes as the "sweet spot" (13 SEER, variable speed air handler, TXV equipped coil).

    3. The other threads on this board have persuaded me that all of the major brands are of comparable quality and the key is the quality of the installation, not the name of the brand.

    4. It appears that in this community the highest regarded installers only offer the highest price brand names. I don't want to pay a premium price for a brand name. How should I deal with that dilemma?

    5. It seems that I should start with the reality of my 1/4 inch liquid line. Based on my experience up to today, I cannot depend on the salesman to provide accurate information about which 2 ton heat pumps are approved for 1/4 inch liquid lines. Once I have correctly identified suitable models, either R-22 or R-410, then I can go looking for installers who deal in those models and whose reputation is sound. What is a source I can turn to for independent information regarding the liquid line size specifications for various models?

    6. If I purchase a model rated for 3/8 inch liquid lines and I do not replace my 1/4 inch liquid lines will the world come to an end? Will the only consequence be a loss in efficiency? Will I prematurely burn out the compressor?

    7. Mr. Kilgore gave me this advice regarding the use of the existing lineset:
    <<Make sure it was soldered with some thing that can handle 410 pressures. We have run into some old systems that were soft soldered and we had to go back with a r-22 system.>>
    How do I as a layman know what my lineset was soldered with? How in the world do I trust any of these salesmen to answer that question?


    Please keep your "cards and letters" coming in. I may be back with additional questions. Thank you all for your assistance.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,311
    Rheem/Ruud may still use 1/4" liquid lines. I don't know for sure.

    If you keep your 1/4" liquid line and use a unit that needs 3/8", you'll lose capacity in both heating and cooling.

    We prefer to change out the line set, even when its the right size, but it is not rquired, RX11 flush will clean out your old lines.

    Since your looking at heat pumps. You should also be looking at the HSPF, and the COP of the units you are considering.
    Those ratings are for its heating efficiency.
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