Results 1 to 8 of 8
  1. #1
    Join Date
    Apr 2009
    Posts
    4
    Post Likes

    Advice for New A/C Install for Condo Unit

    Hello,

    I recently moved into a 1100 sqft open-style loft condo with 9.5 ft ceilings. The building was originally a brick warehouse (built in 1913 and converted to condos in 2002). At the time of the conversion, the developer had the foresight to make sure all units had refrigerant pipes and electrical conduit (but not the wires) roughed-in. They run from the mechanical room of my suite up to the roof.

    I have received a few quotes from contractors in the area (Edmonton, Alberta, Canada) to provide a condensing unit that will be installed on the roof, an evaporation coil to be installed in my existing fan coil unit located in my suite, and to run the required electrical wiring from my electrical box up to the condensing unit. Of course they'll also do all of the required hookups and install a condensation pan and drain.

    There are a few complications with my building, so I would like to get some advice from the experts. First of all, my fan coil is currently controlled by a thermostat that uses 120V instead of the usual 24V. The existing thermostat is a basic digital one that does not have the ability to control cooling (heat only), but one of the contractors I had in to provide a quote confirmed that the cooling control wires do run to the thermostat (they just aren't hooked up to it apparently).

    So question number one is: does anyone know of a digital programmable thermostat that will control both heating and cooling that is designed to work with fan coil units using 120V? I would like to be able to save energy by installing a programmable thermostat, but the only one I can find is the following (and I'm not even sure if it is designed to work with my system): http://www.pecomanufacturing.com/pro..._DataSheet.pdf

    Question number two is with regards to one of the systems I have been quoted: 2-ton, 13 SEER, Bryant (Model 123ANA024) using R-410a refrigerant. This is the system I will most likely go with. Does it seem appropriate for my condo and what do you think of the brand, keeping in mind that the part of the world I live in is not humid and there are only about 2 months a year where A/C is actually needed.

    Question three: the fan coil in my mechanical room has a label that suggests R-22 refrigerant should be used, so I'm a little concerned about switching over to R-410a. Can anyone speak to the possible problems this might cause? The contractor said there should be no problems because the refrigerant lines have not been used with R-22 and because we are putting in a new evaporation coil designed for R-410a.

    Last question: the contractor also mentioned that the new evaporation coil will use a TXV control instead of a regular orifice control. Is this a better technology? What are the pros/cons of one versus the other?

    Thanks to all for their comments and advice.

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    39,099
    Post Likes
    A matched system works a lot better. Is the indoor unit a Bryant? What's the model # of it?

  3. #3
    Join Date
    Apr 2009
    Posts
    4
    Post Likes
    Thread Starter
    When you say the "indoor unit" do you mean the expansion coil that will be installed inside my fan coil unit? Or do you mean the fan coil unit itself? The new expansion coil will be Bryant as well, but I'm not sure of the model number for it as that was not provided by the contractor. The existing fan coil unit (which currently only provides heat) is made by First Co. (model number 36MBXR, with details here: http://www.firstco.com/products/mbxb_hw.asp).

    Thanks.

  4. #4
    Join Date
    Jan 2009
    Location
    Saint Joseph, MI
    Posts
    5,564
    Post Likes
    A matched system includes the air handler/fan coil... not just the coil itself. The cabinet dimensions and fan design can affect performance.

    Get the complete system replaced along with the thermostst. You might also consider a heat pump for heating. It uses 1/2 to 1/3 the heat of the electric resistance heat it sounds like you have now.

    If you can afford to pay a little more up front, you can get a $1500/30% tax credit for a higher efficincy system. In some cases that pays for most of the upgrade.

  5. #5
    Join Date
    Apr 2009
    Posts
    4
    Post Likes
    Thread Starter
    Unfortunately the fan coil (which uses hot water from a central boiler in the building for heating) is considered common property (I don't own or have control over it), so I'm not allowed to replace it without getting condo board approval which is not likely to happen because they want to keep all systems uniform. With that in mind, any comments about my other questions (i.e. a 120V thermostat, Bryant A/C equipment in general, R-410a being ok with the existing system components, and pros/cons of TXV control)? Thanks.

  6. #6
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    39,099
    Post Likes
    The spec sheet shows the part # for R410a TXV. Only concern is that your unit is a "3 ton" unit. Your dealer should check with First Company to see what they think of using a 2 ton outdoor unit on it. May be fine with the right TXV. Certainly need to greatly reduce blower speed.

  7. #7
    Join Date
    Jan 2009
    Location
    Saint Joseph, MI
    Posts
    5,564
    Post Likes
    Quote Originally Posted by kakgungor View Post
    Unfortunately the fan coil (which uses hot water from a central boiler in the building for heating) is considered common property (I don't own or have control over it), so I'm not allowed to replace it without getting condo board approval which is not likely to happen because they want to keep all systems uniform. With that in mind, any comments about my other questions (i.e. a 120V thermostat, Bryant A/C equipment in general, R-410a being ok with the existing system components, and pros/cons of TXV control)? Thanks.
    Ahhh associations. I had a similar issue when I had a condo. I moved. I hoope you can find a good solution. A mismatched coil can work fine, but it will take some extra work to make sure it will matches well. A common boiler is a good idea. A common fan coil "spec" is not IMO. But association don't often have technically compitent people on them that understand any of this.

  8. #8
    Join Date
    Apr 2009
    Posts
    4
    Post Likes
    Thread Starter
    Any comments on 120V programmable thermostat options? Would the one I posted originally work with this system?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.