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  1. #1
    Join Date
    Jul 2008
    Location
    San Diego, CA
    Posts
    8

    Hmm Full or partial replacement of current system....

    I have multiple contractors etimates open (5 of them) and of course each one is a little different (RHEEM VS. PAYNE VS. LENNOX or 2 TON VS. 3TON). I have found one contractor that seems to be pretty honest and the only contractor that actually checked the outside condensing unit ( A 2001 Payne 2 ton) and found it to be just fine. He has reccommended to only replace the indoor furnace unit with a 3 Ton RHEEM SUPER QUIET 80. He has assured me that the outside unit has plenty of life left in it and would function fine with the new 3TON Furnace. He also pushed keeping the current system with the old refrigerant because he was not to excited about the new 410A yet and if we went up to the 3 ton we would have to run a new 3/8" refrigerant line (but thats a whole new issue). He wants to put the 3 TON in so that if we ever upgrade the condensing unit outside in the future, we could go up to 3 TON.

    House Details:
    Upstairs Condominium
    Southern California (90-110 Temps in summer)
    1100 Sq. Ft that includes Large Vaulted ceilings

    The three questions I have are:
    1. One of the contractors included enlarging the duct box from 12" to 16" to accomidate the 3TON output of air, but with the contractor above, this was never mentioned. Should the box be enlarged for the new 3TON RHEEM FURNACE w/ the current 2TON PAYNE CONDENSER?

    2. Is it cost effective and make sense to match up the new 3TON RHEEM with the existing and working 2TON PAYNE Condenser?

    3. New refrigerant (410A) vs. current refrigerant?

  2. #2
    Join Date
    Apr 2007
    Posts
    6,285
    R410A is fine to use it's not new and will be in every new piece of equipment after starting @ 2010.

    By what you have stated you need to keep looking for contractors. Ask your contractors for load calculation. ACCA Manual J,D or something =.

  3. #3
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    Quote Originally Posted by Ryguymedia View Post
    I have multiple contractors etimates open (5 of them) and of course each one is a little different (RHEEM VS. PAYNE VS. LENNOX or 2 TON VS. 3TON). I have found one contractor that seems to be pretty honest and the only contractor that actually checked the outside condensing unit ( A 2001 Payne 2 ton) and found it to be just fine. He has reccommended to only replace the indoor furnace unit with a 3 Ton RHEEM SUPER QUIET 80. He has assured me that the outside unit has plenty of life left in it and would function fine with the new 3TON Furnace. He also pushed keeping the current system with the old refrigerant because he was not to excited about the new 410A yet and if we went up to the 3 ton we would have to run a new 3/8" refrigerant line (but thats a whole new issue). He wants to put the 3 TON in so that if we ever upgrade the condensing unit outside in the future, we could go up to 3 TON.

    House Details:
    Upstairs Condominium
    Southern California (90-110 Temps in summer)
    1100 Sq. Ft that includes Large Vaulted ceilings

    The three questions I have are:
    1. One of the contractors included enlarging the duct box from 12" to 16" to accomidate the 3TON output of air, but with the contractor above, this was never mentioned. Should the box be enlarged for the new 3TON RHEEM FURNACE w/ the current 2TON PAYNE CONDENSER?

    2. Is it cost effective and make sense to match up the new 3TON RHEEM with the existing and working 2TON PAYNE Condenser?

    3. New refrigerant (410A) vs. current refrigerant?

    1. Communicate with your contractors. Find out exactly what they want to do in detail. We can't see it therefore we can't give you recommendations on size of system, design of ductwork, etc.etc...

    2. Your systems should always match. Especially when it comes to warranty issues. A typical warranty is only valid if the system components are matched properly. Not to mention is saves money in labor costs. But a 7 year old unit should last a good while, provided it was installed properly and hasn't had too much unusual running conditions.

    3. New refrigerant is R-410A. Old is R-22. R-22 will no longer be in new systems as of 2010. So you keep yours now and new coil and then come 5 years, you will need to do all the work all over again anyhow. Might as well do it now. Cause prices will only continue to increase.

    Oh yeah, and R-410A has been around awile now. Its not new. Its just newer. And shouldn't scare anyone.


    So in short, look at full system replacement with R-410A refrigerant. It will cost more now but will save in the long run. Purchase the most efficient unit you can possibly afford as it will save you on your utilities bills. And remember to purchase the contractor, not the brand. Installation is key. An improperly installed system will never work right no matter what brand it is.


    Any more questions???
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  4. #4
    Join Date
    Jul 2008
    Location
    San Diego, CA
    Posts
    8
    Can these tests be done on a furnace that no longer functions?

  5. #5
    Join Date
    Sep 2002
    Posts
    13,212

    A 50% increase in cooling capacity is a pretty radical jump

    What do the heat gain load calculations say the cooling requirements are? You need to use somebody who will measure, test, and verify - not someone who will guess.

    If you really need a 50% increase in cooling now - how has the house been cooled for the last seven years?

    Is a "super quiet 80" a gas fired furnace? And if so; is that really a good choice in southern CA? I am in far off NJ but it sure seems like a heat pump would be the superior choice to me from here.

    PHM
    ----------



    Quote Originally Posted by Ryguymedia View Post
    I have multiple contractors etimates open (5 of them) and of course each one is a little different (RHEEM VS. PAYNE VS. LENNOX or 2 TON VS. 3TON). I have found one contractor that seems to be pretty honest and the only contractor that actually checked the outside condensing unit ( A 2001 Payne 2 ton) and found it to be just fine. He has reccommended to only replace the indoor furnace unit with a 3 Ton RHEEM SUPER QUIET 80. He has assured me that the outside unit has plenty of life left in it and would function fine with the new 3TON Furnace. He also pushed keeping the current system with the old refrigerant because he was not to excited about the new 410A yet and if we went up to the 3 ton we would have to run a new 3/8" refrigerant line (but thats a whole new issue). He wants to put the 3 TON in so that if we ever upgrade the condensing unit outside in the future, we could go up to 3 TON.

    House Details:
    Upstairs Condominium
    Southern California (90-110 Temps in summer)
    1100 Sq. Ft that includes Large Vaulted ceilings

    The three questions I have are:
    1. One of the contractors included enlarging the duct box from 12" to 16" to accomidate the 3TON output of air, but with the contractor above, this was never mentioned. Should the box be enlarged for the new 3TON RHEEM FURNACE w/ the current 2TON PAYNE CONDENSER?

    2. Is it cost effective and make sense to match up the new 3TON RHEEM with the existing and working 2TON PAYNE Condenser?

    3. New refrigerant (410A) vs. current refrigerant?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #6
    Join Date
    Jul 2008
    Location
    San Diego, CA
    Posts
    8

    Hmm

    Quote Originally Posted by Poodle Head Mikey View Post
    What do the heat gain load calculations say the cooling requirements are? You need to use somebody who will measure, test, and verify - not someone who will guess.

    If you really need a 50% increase in cooling now - how has the house been cooled for the last seven years?

    Is a "super quiet 80" a gas fired furnace? And if so; is that really a good choice in southern CA? I am in far off NJ but it sure seems like a heat pump would be the superior choice to me from here.

    PHM
    ----------
    We purchased the condo a year ago and the a/c has never functioned properly!!! I cannot go by "how it use to work" since it has been over a year for us and longer than that since the previous owner hasn't occupied it for a year or so before the purchase.

    Can you run a heat gain load calculation with a furnace that currently is not functioning?

  7. #7
    Join Date
    Apr 2007
    Posts
    6,285
    Quote Originally Posted by Ryguymedia View Post
    We purchased the condo a year ago and the a/c has never functioned properly!!! I cannot go by "how it use to work" since it has been over a year for us and longer than that since the previous owner hasn't occupied it for a year or so before the purchase.

    Can you run a heat gain load calculation with a furnace that currently is not functioning?

    Heat gain is based on the structure/location/orientation/shading not the existing system. HVAC Calc

  8. #8
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Manual J load calc.,from www.acca.com

  9. #9
    Join Date
    Jul 2008
    Location
    San Diego, CA
    Posts
    8

    Thumbs up Thanks for the concern....

    Quote Originally Posted by dash View Post
    Manual J load calc.,from www.acca.com
    Thank you for the concern, everyone in this thread has been very helpful! I appreciate this website and the professionals that help make it what it is.

  10. #10
    Join Date
    Sep 2002
    Posts
    13,212
    The heat gain / loss calculations are done on the structure. That way you know which equipment would best suit the circumstance.

    1. Accurately determine what is required.

    2. Properly install equipment which will fill the rerquirements.

    No; the present equipment isn't a factor.

    How cold does it get there during the heating season? Is it ever below zero for long periods of time?

    And how long is the heating season?

    There is a bit more to adding 50% more cooling capacity than just installing the equipment. One of those things is the air flow requirements.

    And, if the original equipment was skimped on - I doubt that they were generous with the air duct sizing.

    With proper design all the puzzle pieces have to fit together well. You can't just put the odd ones back in the box.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  11. #11
    Join Date
    Apr 2007
    Posts
    6,285
    Quote Originally Posted by Ryguymedia View Post
    Thank you for the concern, everyone in this thread has been very helpful! I appreciate this website and the professionals that help make it what it is.

    This will give a good understanding about oversizing.

    By the way ARI and contracting business are close to home here
    Attached Images Attached Images

  12. #12
    Join Date
    Jul 2008
    Location
    San Diego, CA
    Posts
    8

    Confused

    Quote Originally Posted by Poodle Head Mikey View Post

    How cold does it get there during the heating season? Is it ever below zero for long periods of time?

    And how long is the heating season?

    There is a bit more to adding 50% more cooling capacity than just installing the equipment. One of those things is the air flow requirements.

    And, if the original equipment was skimped on - I doubt that they were generous with the air duct sizing.

    With proper design all the puzzle pieces have to fit together well. You can't just put the odd ones back in the box.

    Thank you for the input!

    We are replacing the furnace because it is what blows the A/C and the piece that has quit on us. We are fortunate enough to live in San Diego and the winters are very mild so heating isnt a huge issue. With that, over the past 15-20 years, the area I live in has gotten hotter and hotter in the summer and we tend to have over 90's a good portion of the year with many weeks over 100 degrees.

    The original duct work as far as I have been told by all the contractors is in great condition! One proposal by a contractor wanting to go from the current 2 ton to 3 ton put in the proposal that the hole in which the air enters into the duct work, i think he said intake box, needs to be changed from a 12" diameter hole to a 16" hole to accomidate the larger amount of air flow. Another contractor also wants to go up to 3 ton but did not mention this as something that needs to be done - Have you found that a larger intake box is needed for a 3ton vs. a 2 ton?

  13. #13
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    If the old duct system was sized correctly,not larger then needed,the duct system will need rework/changes of some kind for a three ton system.Can't tell from here if what they propose is enough of a change.


    Duct systems are rarely lerger than needed and often smaller than needed.

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