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  1. #1
    Join Date
    Aug 2012
    Posts
    9

    Replacement of Condo's HVAC Questions

    Hi guys - hoping I could get some advise on how best to proceed,

    I have a 3rd floor, vaulted ceiling (in living/dining) condo (1100 sqft) in Houston with a 2.5 ton condensor outside and indoor furr-down air handler (installed '98.) The current SEER rating is 8 and its leaking freon I am trying to have it replaced now. I have received 4 quotes with a wide variation in price and equipment choices so I wanted some help deciding how best to proceed. All 4 quotes indicate I should remain with a 2.5 ton system and go to equipment with a SEER 14 rating.

    1. Based on my understanding, SEER is an efficiency rating - and since I have a furr-down unit, am I stuck with a max efficiency SEER 14? Also my understanding is aside from tonnage, the SEER ratings of the air handler and outside condenser have to the match? Do I have any options?

    2. I do have attic access with a very large open area above the central area where the furrdown unit is in the ceiling and the ductwork must be - but I get the general impression from reading here that putting anything in the attic is not a good idea?
    3. Should I consider some sort of renovation to place a different air handler in the unit? I am posting a small version of the floorplan. The intake is located in the ceiling (non cathedral) of the hallway. The bedrooms are non-cathedral. The living/dining is cathedral ceilings.

    4. My father has a pref for Trane and as such, it seems the outdoor unit is an XB14 in the quotes. The indoor-unit gets more interesting. Multiple contractors are telling us that instead of using Tranes XB4FWF air handler we should use First Company's 30HX-10 Fan Coil as its the same thing and Trane rebrands them. I am confused though - the Trane seems to have a all aluminum fan coil while First Company's website says mixed copper and aluminum. How is this possible? Should I even trust this or go along with it?

    Any thoughts/comments on what I should do here? I want to choose a contractor based on their merits, but also on ensuring they are recommending the most cost effective system I can for the unit as I am moving my parents in as their retirement home and I dont want to have to worry about things breaking/repairs or outrageous electricity bills. I am hampered by my lack of knowledge in these furr-down based units on what I should expect to see quoted to me.

    thanks for your help!
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    Last edited by kapvixa; 08-12-2012 at 11:05 AM.

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,448
    I found a 4FWDA that looks a lot like the First Co. It's possible that First Co. made it for Trane but modified it for Trane like an all aluminum coil. I saw no ratings for the XB14 and the little air handler. But unless you have a high efficiency indoor blower motor, which doesn't seem to be the case, you won't get above 14 SEER anyway so buying an outdoor unit capable of more doesn't make sense. If you stayed all Trane, you could put an extended labor warranty on the system to protect against expensive bills in the future.

  3. #3
    Join Date
    Aug 2012
    Posts
    9
    Thanks for the response - So after much more research, I don't see the value in attempting to make any structural changes, we would never recover the costs anytime soon.

    It looks like we would be going with a XB14 on the outside and now its just the inside part that's I am trying to determine. I spoke to one of the companies and they said that the information provided was in error and that Trane's furr-down unit is possibly made by Texas Furnace but either way, they couldn't get it for several weeks at the earliest.

    So the question I have - is it worth saving money up front and getting the First Company 30HX-10 now (due to the error in one of the quotes, the company is honoring a 10 year parts and labor warranty on it) or wait 3 weeks and obtain the Trane unit which will cost a sig bit more? Is the all aluminum coils in the Trane unit worth it vs the First Company unit?

  4. #4
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,369
    First Company has been making furdown fan coil units for apartment/condo use for years. The main caution here is that any indoor unit selected must be an ARI rated match for the selected outdoor unit.

    With furdown systems you have the advantage of the ductwork and air handler being inside the condo vs. up in a blazing hot attic. That is already an efficiency boost over an equivalent SEER and tonnage with the air handler and ducts in the attic. The drawback to furdown systems is often the return air methods suck on the building cavities, and draw in air from places you don't want it to come from.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #5
    Join Date
    Aug 2012
    Posts
    9
    I tried getting the AHRI ratings on the combo from both the AHRI site and the FIrst Company site but I cannot pull up the combo of the Trane XB14 (4TTB4030E1) with a First Company 30HX at all. Two of the companies insist it will work - but how do I verify it?

  6. #6
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,369
    Ask to see their info that says the combo will work. Should be a document either from a manufacturer or ARI (Airconditioning and Refrigeration Institute, which assigns nominal tonnage numbers based on matched systems to all equipment manufactured and/or sold in the USA)

    If they can't or won't show it to you, move on.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  7. #7
    Join Date
    Aug 2012
    Posts
    9
    Yup. First Company confirmed it will not work. The max they can get is SEER 13 with their units to a different outdoor unit. Multiple companies have told me Trane doesnt make any furdown units period (thought their website shows one). Now trying to figure out if there are any SEER 14 compatible units out there. Who else (manufacture wise) should I look into? I checked Carrier's site - no furdown units shown there. Any other ideas?

  8. #8
    Join Date
    Aug 2012
    Posts
    9
    Is it ok to go up in capacity to get the same efficiency or is not worth it? Aka - Based on the AHRI # 5291966 -
    The Trane outdoor 4TTB4030E1 - rated 30,000 BTU, 2.5 tons combined with an inner fur-down of 4FWFA036A - rated 36,000 BTU works with an 28,600 BTU, EER 12 and a SEER of 14, but if I go down to the 30A airhandler - rated 30,000 BTU capacity, theres nothing listed for compatibility.
    Since I am efficiency limited in the first place thanks to the furdown - do you think we are making too much fuss trying to get 14 SEER vs 13 SEER and is it worth it down the line for cost/efficiency concerns?

  9. #9
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,448
    If the mfr rates a combo, it is fine. 1/2 ton bigger fan coil is common.

    Goodman's ANCF is another alternative.

  10. #10
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,369
    If your ducts are inside the building and not in the attic, you are doing better at 13 SEER than a 14 SEER system with ducts in the attic. Duct losses work against efficiency ratings and actual delivered tonnage big time when the ducts are not in the same space as the air conditioned air.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  11. #11
    Join Date
    Aug 2012
    Posts
    9
    All the ducts are in the ceiling and not in the attic - when I when up there to check, there is full drywall above all the locations of the furdown/ducts and insulation on top of it. Aside from the pipes, no evidence of the system in the attic. Just checked into the goodman option - can max it at 13 SEER.

  12. #12
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,369
    I'd say go for the proper ARI rated match at 13 SEER and enjoy. Many people do not know that efficiency and delivered capacities of a/c split systems take a big hit once equipment and ducts go up into a non air-conditioned attic.

    I'll also let you in on a little secret: there's no way to field verify SEER. EER, yes. SEER, no.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  13. #13
    Join Date
    Aug 2012
    Posts
    9
    OK, making sure I am not misunderstanding something here - the facts my ducts are in the ceiling (lowered) and not in the attic itself is just as bad as being in the attic? Aside from the pipes/wires to the existing air handler - there is nothing else up in the attic. Everything is below the drywall under the studs. I should still expect a huge hit on efficiency when it is installed from what's its rated nonetheless?

    The different installers are giving the run around telling me what works and what doesn't without providing certificates. I've now had 4 different people tell me something's approved that the certificate doesn't exist for or First Company says doesn't work. It's kinda frustrating actually - I would think they would want to sell me an approved system if they are listed as authorized resellers of the different manufactures. Goodman manufactoring's rep said they couldnt tell me anything about workable combinations, I would have to speak to their authorized resllers and provided me three in the area - one of which is the one claiming false ratings and matches we already know cant work! So weird.

    I'm hesitant to have someone come in an install something if they can't be honest up front. I've not haggled any of the quotes cost wise and don't really intend to. I never thought replacing the AC with an approved combination would be so frustrating.

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