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  1. #1
    Join Date
    Oct 2007
    Posts
    5

    Adding A/C to existing Thermopride Oil Furnace

    We are renovating a ranch house in CT. We have ripped out the old ducting in the areas of the house we are renovating and are planning to add A/C. The house has 1500 sf on main level and 600 sf on lower level. We currently rely on an early 1990s Thermopride Oil Furnace for heat, which works well.

    The house is "California style" with glass walls in the living area facing east.

    The contractor has judged it to require 5 tons. How do I know that he properly performed Manual J calc? Is there a way to tactfully confirm that he didn't make a guess based on all of the glass? It doesn't get above 90 degrees too often and we are looking for A/C to dehumidify as much as to cool.

    The HVAC contractor has recommended the following system:

    Carrier Oil highboy 58CMA
    5 ton Coil CNRVP
    5 ton 24ACR (freon)
    Condensate pump
    Programable thermostat-1 zone

    There is also:
    an option to upgrade to a Thermopride furnace and
    an option to upgrade to 5 ton 24APA5 (puron).

    As our current furnace works well, we wonder whether it is a good idea to keep it and just add the coil and condenser. We have the furnace serviced yearly and the service guys always say the unit is running strong and could have 10-15 years ahead of it.

    On the condenser, it seems that Puron makes sense and for a few $$$ more the upgrade is worthwhile.

    Finally, we would like to place the condenser approximately 50 feet away from the coil. The condenser will be on ground level and the coil will be at the height of the furnace. Given the need to run the lines out through the ceiling there is the need to elevate from the coil 6 feet or so and then descend from the ceiling to ground level-approx 9 feet. Will this distance cause any problems for such a system.

    Thanks for taking a look.

  2. #2
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    5 Ton's in CT?

    Find another contractor asap. IMO
    Karst means cave. So, I search for caves.

  3. #3
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,369
    Is the R410a system considerably more than the R22 system? I've heard they are similar if not equal in terms of price. I guess if you factor in a lineset flush/replacement, the R410a system could cost a bit more.

  4. #4
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    I agree, 5 tons!? Yikes. Those window are made out of thin plastic?

    That Thermopride is going to last forever, I see no reason why it needs to be replaced..

    Find another dealer, and just add A/C to the home.

    For Manual-J, on top of the page, is the HVAC Calc that you can down load for yourself for $50.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,765
    Get anothe estimate or 2.

    As with the others, 5 tons sounds too big.
    It could be correct, depending on how many windows, what size they are, and what way they are facing.
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    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,922
    I agree too, sounds outrageous.

    Besides, a 1990s Thermopride is just getting broken in!

  7. #7
    Join Date
    Oct 2007
    Posts
    5
    I have run the Manual J on HVAC-Calc and it spits out 5 tons. It seems that the glass walls add significantly to the requirement for cooling.

    Nevertheless, since we are more concerned with humidity control than a cold house, would we be mistaken to look at a 4 ton system? What is the consequence of going too small?

    Thanks.

  8. #8
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Is the windows single pane, along with the others in the house?

    If so, I'd suggest on spending the money to upgrade those windows now, then redo the Manual-J. No point of going on your results now, and then upgrade the windows a few years down the road, and maybe learn that the 5 ton may be oversized by 2 1/2 ton.

    I know on my house, I could of gone down to 1.5 on my system after I put in new windows.

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