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  1. #1
    Join Date
    Oct 2005
    Posts
    7
    I know you guys don't like DIY posts, but I'm hoping this one is ok. It relates to thermostat problems.

    Furnace in my new home seemed to be working ok until last night. Here in indy, we got a blast of storms, wind and cold... I suddenly noticed it very hot in the house, with most of our rooms measuring 80 degrees despite having the thermotat set at 74 (yeah we like it warm, but not 80 degree warm).
    Since it had been working all fall flawlessly, and I had a tech out to inspect/service the furnace back in september, I got curious as to what would be causing this and broke out a thermometer. All my rooms read 80 degrees, even the hallway where my thermostat is at, but the thermostat was reading 74.
    I found some posts here about air leaking through wiring holes in the wall behind the thermostat, and sure enugh that's what the problem ended up being. I plugged the hole up, and instantly my themrostat was reading 79.

    Saved myself a service call with a simple fix.
    So I wanted to say thanks for the wealth of information here, that can help homeowners make informed decisions, and with small easy fixes.

    While searching though, I found alot of posts about cycling and how it relates to thermostats. Mine is digital, and doesn't have a heat anticipator or cycle setting on it (I think it's a cheap one). Anyways, it seems to be cycling as follows; about 12 minutes off, 10 minutes on. thermostat is set at 74, outside temp is 30. Humidity in house is 38%, outside is 62%. heat is 80,000btu high efficiency furnace.

    This is my first home with central air heating, so I'm not really sure how it should be performing. It seems fine to us, but reading through many of the posts here really makes me wonder. Should we look into a better thermostat where we can set the cycles per hour? or are we running ok?

  2. #2
    Join Date
    Apr 2005
    Location
    Kingston Ontario Canada
    Posts
    1,234
    Originally posted by alm
    I know you guys don't like DIY posts, but I'm hoping this one is ok. It relates to thermostat problems.

    Furnace in my new home seemed to be working ok until last night. Here in indy, we got a blast of storms, wind and cold... I suddenly noticed it very hot in the house, with most of our rooms measuring 80 degrees despite having the thermotat set at 74 (yeah we like it warm, but not 80 degree warm).
    Since it had been working all fall flawlessly, and I had a tech out to inspect/service the furnace back in september, I got curious as to what would be causing this and broke out a thermometer. All my rooms read 80 degrees, even the hallway where my thermostat is at, but the thermostat was reading 74.
    I found some posts here about air leaking through wiring holes in the wall behind the thermostat, and sure enugh that's what the problem ended up being. I plugged the hole up, and instantly my themrostat was reading 79.

    Saved myself a service call with a simple fix.
    So I wanted to say thanks for the wealth of information here, that can help homeowners make informed decisions, and with small easy fixes.

    While searching though, I found alot of posts about cycling and how it relates to thermostats. Mine is digital, and doesn't have a heat anticipator or cycle setting on it (I think it's a cheap one). Anyways, it seems to be cycling as follows; about 12 minutes off, 10 minutes on. thermostat is set at 74, outside temp is 30. Humidity in house is 38%, outside is 62%. heat is 80,000btu high efficiency furnace.

    This is my first home with central air heating, so I'm not really sure how it should be performing. It seems fine to us, but reading through many of the posts here really makes me wonder. Should we look into a better thermostat where we can set the cycles per hour? or are we running ok?
    Hi alm: I'm not a tech or anything, just a homeowner, but I do know some things about air condtioning and furnaces etc. This being said, I would like to say that they anticipator is what makes the appropriated piece of equipment come on or shut down in relation to the setpoint that you have chosen. How long it stays on or how long it stays off has nothing to do with the thermisitat per se. Your heat loss or your heat gain of your house determins this. Yes good thermistats have a feature build-in that will not alow your system to cycle more then few times a hour to protect compressors etc. I also found out personally that when the hole where the wires come through the wall SHOULD be plugged. Mine was not and when I asked the installing dealer about it he said " we normally don't plug the hole". These are the kind of things that infuriate me about contractors. I had complained about the thermistat short cycling too, two or three times to him. I still think my heatpump was not set up properly from the beginning as I had to replace the txv in only three years. Since it has been fixed ( I plugged the hole) and txv replaced the heat pump works much better.
    Hope this helps some

    Thorton

  3. #3
    Join Date
    Oct 2001
    Posts
    6,966
    another trick.....is if your furnace is in an unheated basement?the return duct holds the filter just before the unit.make sure that the filter has a cover over where it slides into the duct.that is your return air and if the basement is cold so will your return/mixing be....without the duct being closed at the filter access.
    "when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY

  4. #4
    Join Date
    Oct 2005
    Posts
    7
    Well, pluggin the hole made perfect sense. I hadn't though of it until I started searching for thermostat problems on this forum. Once I popped the thermostat off, and felt the breeze coming from the half dollar sized hole, it was obvious what the problem was.
    I had radiators in my old house, so I'm not really sure how long this thing should be running on and off. We had central air as a kid, but I never paid much attention to it all back then.
    The house is old and not very well insulated. The hole behind the thermostat was just one of many holes that need plugging I imagine.
    But back when i had it serviced, the heat was only coming on once an hour or so because it was much warmer outside then. from what I've read here I think my cycling times (about 3 cycles an hour?) should be ok for 30 degrees outside, but just wanted to be sure before i call my service guy up and bother him with stupid questions.

    Just caught the other post. No basement here. Electronic air cleaner with a cover on it. I don't think I have any leaks, but couldn't be sure. I'm just really wondering how the previous owners never noticed this? They must have kept the heat setting really low to compensate or something.


    [Edited by alm on 11-16-2005 at 06:39 PM]

  5. #5
    Join Date
    Oct 2005
    Posts
    7
    Well I called my service guy up and he said that the run time was fine for my furnace at those temps. He said the wiring behind the thermostat was common, and that I should try to plug the hole up in the attic where the wire comes out also. He recommended weatherproofing to avoid losing heat so quickly, but it's such an old house I don't know where to begin. No insulation under the floor joists might be a good start, since the floors are quite cold. Not going to be fun, i hate spiders. So much time and so little money... lol
    thanks again.
    -r

  6. #6
    Join Date
    Jul 2005
    Posts
    717
    ALMS,you said;.... "Anyways, it seems to be cycling as follows; about 12 minutes off, 10 minutes on. thermostat is set at 74, outside temp is 30. Humidity in house is 38%, outside is 62%. heat is 80,000btu high efficiency furnace.

    Your going to have a high fuel bill if it runs at this cycling rate for a few days. At that rate,if your outside temp ever got down to zero F, your unit would probably run continuously, or more (lol)

    Take note;many homes in a region of N Ont.,Canada the statistics are;
    average 1500 sq ft home with finished heated basement,well insulated, 74000 btu oil ,.65 nozzle, temperature outside is 20 f, inside T stat is set at 72 F, furnace cycle ONCE only for 6 minutes an hour.
    As in many past years, when the outside temp drops to -10 F or less the burner's cycle may only occur twice in an hour @ 5 minutes each.

    One big difference from yours,eh?



  7. #7
    Join Date
    Oct 2005
    Posts
    7
    I've seen your posts on this issue. I side with everyone else.

  8. #8
    Join Date
    Jul 2005
    Posts
    717
    Originally posted by alm
    I've seen your posts on this issue. I side with everyone else.
    SO NOW YOUR GOING TO GET DUPED AGAIN

  9. #9
    Join Date
    Jul 2002
    Location
    St Paul, Minnesota
    Posts
    3,468
    alm, take your model of thermostat to the internet search engines and find a link to a manual. Download it and it will tell you how to set a cycle rate. I would be happy with three times an hour in an old house.

    Now post the model and serial number of the unit. Unless you have to crawl around in the attic to get it. If it is an attic unit, have the contractor check it every year for your piece of mind. Techs love crawling around in attics.

  10. #10
    Join Date
    Jul 2005
    Posts
    717
    [QUOTE]Originally posted by MikeJ
    [and it will tell you how to set a cycle rate. I would be happy with three times an hour in an old house.

    you say;.. 3 cycles an hour, ,.. and some others say 4 or 5.
    wow, no wonder there's going to be a shortage of fuel in the near future

  11. #11
    Join Date
    Oct 2005
    Posts
    7
    From what paperwork i have, it's a PS9C20N080UP11 (not sure if zero's or O's) Its a york.
    The thermostat is a honeywell ct3200, and has no information on setting heat anticipation or cycles per hour.

    To be honest, after talking with my service guy, I think I'd rather leave it (if it ain't broke don't fix it) for the time being. The temperature is just fine and we end up with a 2 degree swing in our entry room, but it has lots of windows and a patio door there. All other rooms have no noticeable hot/cold swings and comfort is just fine for us.

    I've read all the other posts that started out like this one, and can see where it's heading. When I purchased the home, I found a service guy and setup to do my seasonal maintenance in the spring and fall. He seems pretty straight up with me, and isn't rushing to sell me stuff. He's only been out once so far, but that visit and our recent phone conversation makes me feel comfortable with his opinions. He seems to agree that the furnace should be running more often near design temperature, and so do many of you. So I am happy with that.

    I think money would be better spent sealing up the house wherever possible.


  12. #12
    Join Date
    Jul 2005
    Posts
    717
    Alm, on the honeywell T stat ct 3200, there is a "A-B" setting. In your case, try A out one full turn, and B in tight. this will have an effect on your cycling.

    Try it, you may like it

  13. #13
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,508
    Originally posted by deejoe
    ALMS,you said;.... "Anyways, it seems to be cycling as follows; about 12 minutes off, 10 minutes on. thermostat is set at 74, outside temp is 30. Humidity in house is 38%, outside is 62%. heat is 80,000btu high efficiency furnace.

    Your going to have a high fuel bill if it runs at this cycling rate for a few days. At that rate,if your outside temp ever got down to zero F, your unit would probably run continuously, or more (lol)

    Take note;many homes in a region of N Ont.,Canada the statistics are;
    average 1500 sq ft home with finished heated basement,well insulated, 74000 btu oil ,.65 nozzle, temperature outside is 20 f, inside T stat is set at 72 F, furnace cycle ONCE only for 6 minutes an hour.
    As in many past years, when the outside temp drops to -10 F or less the burner's cycle may only occur twice in an hour @ 5 minutes each.

    One big difference from yours,eh?
    Sounds like the installing contractor fubed this job, should it be running 100% when it's -10F outside?




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