Page 2 of 2 FirstFirst 12
Results 14 to 22 of 22
  1. #14
    Join Date
    Feb 2017
    Posts
    4
    Post Likes
    Thread Starter
    Thank you to all who replied. I bought the 100k 987 Bryant Modulating furnace and it's solved the problems beautifully. I'm hoping others will benefit from hearing about this because while there's a lot of info out there about these modulating furnaces, I couldn't find owner reviews nor did any of my friends or neighbors have a modulating furnace.

    I appreciate the advice to seal the house, so I got a full energy audit including a blower door test. Turns out my house is at standard for air infiltration. It's just a really big house subject to occasional strong winds. The bigger problem is that there's no easy way to seal the house and 90% of ducts are in conditioned spaces. It did reveal leaky ducts in my attic and I will seal those, but that area is actually serviced by my other furnace.

    I had several HVAC companies look at providing a heat pump but due to the size and desire for more heat rise they all recommended against it.

    Upon removal of the old furnace I discovered it had significant rusting in the secondary and looked like it was rusted through in a couple places. So it was a good move to replace it.

    Going from the old 88k 1-stage to a 100k modulating addressed my problems. I calculated that at the low 40% I'd be getting about 20% less less, and at 100% it would be twice what I was getting. So now I can setback as much as I want and the house is heating up 1 degree in under 15 minutes, but never more than it needs. It only gets to 100% when I bump up the furnace many degrees for a setback. More of the time it runs pretty quiet at 40-60% and it does feel more comfortable as it stays on longer. My house never swung several degrees because of its size but I do feel more comfortable. Cost wise I was able to benefit from 3 separate rebates including one from Carrier due to my prior model having a recall so the cost wasn't that much more than a 2 stage.

    The only things I don't like are the Connex thermostat, which I posted separately, and I'm still having troubles with some fault conditions (hi-limit) that my HVAC company is working on. It's definitely important that not only a good company but a good installer does it. My first installer ran out 10 min after getting it running without any adjustments, but the second guy really knew his stuff and spent hours adjusting the gas pressure and replacing a few parts. This thing is a lot more finicky than my old furnace.

  2. #15
    Join Date
    Jun 2006
    Location
    Richmond, VA
    Posts
    3,802
    Post Likes
    Quote Originally Posted by George98034 View Post
    The only things I don't like are the Connex thermostat, which I posted separately, and I'm still having troubles with some fault conditions (hi-limit) that my HVAC company is working on. It's definitely important that not only a good company but a good installer does it. My first installer ran out 10 min after getting it running without any adjustments, but the second guy really knew his stuff and spent hours adjusting the gas pressure and replacing a few parts. This thing is a lot more finicky than my old furnace.
    This makes me nervous.....hi limits are indicating the duct is too small for the bigger furnace - so you DO NOT fix high limit trips by changing parts or fudging gas adjustments.... It's just a furnace and just works over a wider range it shouldn't be finicky
    I wish I had a $1.00 for every response I deleted.....

    "Decidedly Superior in a twisted pathetic way".....

  3. Likes CEAS-AC-TECH, kdean1 liked this post
  4. #16
    Join Date
    Jul 2014
    Location
    West Columbia, SC
    Posts
    125
    Post Likes
    Agreed... nervous. It is heating faster because it is dumping hotter air into the room because your airflow has NOT improved and the unit is therefore overheating; hence, you are hitting the high limits. Changing parts is merely tampering with the high limits to allow it to overheat more, which is unsafe.

    Honestly, I think at this point your best bet is to find a third contractor in your area now to redo the duct work and verify the high limits are set to their factory safety settings with OEM specified parts and also verify the gas pressure is proper for your unit.

    Realistically a bigger unit should NOT be delivering hotter air only MORE airflow about the same temp. I hope that makes sense that you cannot just drop a bigger unit in without making changes to the air delivery system as well.

  5. #17
    Join Date
    Jan 2008
    Posts
    2,843
    Post Likes
    Who would have thought... going to a bigger furnace is causing limit trips.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  6. Likes lentz liked this post
  7. #18
    Join Date
    Oct 2006
    Location
    The Beach
    Posts
    930
    Post Likes
    Putting a larger furnace in is a bad idea if you so not increase the duct size so the air flow is not restricked. That high limit is in there for a safety reason. Do you not realise you are doing something wrong. The wrong kind of filter will cause this problem also.
    Blue Fox

  8. #19
    Join Date
    Jul 2014
    Location
    West Columbia, SC
    Posts
    125
    Post Likes
    Let's not give the homeowner a bad time - It is completely understandable that 1 degree per hour is not satisfactory when the homeowner probably goes to work and does not want to leave the system running all day when gone to pay to heat the house with no occupants nor does the homeowner want to wait until 3 am in the morning after getting home from work to satisfy the thermostat. The problem here is that after spending money for windows, heatloss testing, and a new system the contractors have still not delivered satisfaction and now they are voiding his warranty and making the system unsafe. It is NOT his fault that the contractors in his area stink. A homeowner is not expected to know about duct work and airflow. That is something the homeowner probably paid a pro over $1/hr to get right only to be let down... and now to poke at this situation like some of these condescending posts is not at all funny. I know it is easy to do when we all see stupid stuff all day, but each time we see a messed up system someone paid good money and got substandard work.

    The constructive comments have xplaining duct work knarenhelpful
    Last edited by beenthere; 03-27-2017 at 04:26 PM. Reason: Price

  9. #20
    Join Date
    Jan 2008
    Posts
    2,843
    Post Likes
    Wizz - I believe he was informed in post #2 this was a bad idea.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  10. #21
    Join Date
    Jul 2014
    Location
    West Columbia, SC
    Posts
    125
    Post Likes
    That is true but another contractor gave conflicting information doing the job we wouldn't have done. Then another contractor comes along and Messes with the system.

  11. #22
    Join Date
    Jan 2004
    Location
    PA
    Posts
    73,772
    Post Likes
    Since when the OP clocked his gas meter, and found that it only had a 60,000 input, and not the 88,000 whatever it was suppose to be. The choice to go up to 100,000 Input was a bad one. When he knew the input had been reduced to lower the temp rise on the furnace.

    While not good to bash him. He does bare some responsibility for the situation. A good tech would have been able to get the firing rate of the old furnace up, and that would have decreased the recovery time.

    If the new tech is put in a higher temp limit, it just harms the heat exchanger.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  12. Likes NETWizz liked this post
Page 2 of 2 FirstFirst 12

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.