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  1. #1
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    Default programable thermostat defective?

    Howdy programmable thermostat digital read out of the time doesn't show the #s clearly and the heat isn't coming up from the last setting to the next which is 5% higher. So how do you know if its the thermostat of the furnace?
    Figure i will replace the thermostat as its cheaper then a service call first . What do you think?

  2. #2
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    Default Re: programable thermostat defective?

    If the thermostat is battery operated then hopefully you changed the batteries first thing.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
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    Default Re: programable thermostat defective?

    Always try to ISOLATE the problem before you waste good money on the parts substitution method and buy parts you may not need.

    Canuk has a good point in checking the batteries.

    Also consult the wiring diagram that came with the t-stat to make sure you have it wired correctly & it is compatible with your furnace/boiler.

    Check if they specify a certain setting with any heat anticipator on the t-stat that may or may not be present.

    If this is a 2-wire t-stat, and none of the above measures work, short the 2 wires of the t-stat together either at the burner/furnace or at the t-stat & see if it then works properly; if it does, the t-stat is faulty, is wired incorrectly, or is incompatible with your furnace.
    Last edited by NashuaTech; 11-24-2010 at 02:58 PM.

  4. #4
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    Default Re: programable thermostat defective?

    As usual NashuaTech rocks

    --- to add -- *if* you test by shorting the 2 heat wires together make sure to disconnect from the thermostat first to reduce any possibilty of dmage to the logic circuit.

    Most of the digital thermostats I've seen usually don't have anticipator adjustments per se -- unlike the mechanical stats.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  5. #5
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    Default Re: programable thermostat defective?

    Howdy thanks for the info.
    I did check the batteries and got a replacement digital thermostat and it working. Am concerned that the temp is a few degrees less then what the programed temp is. so programed to be 70* but temp at 68* would of thought at 68 it would turn on the furnace?
    As record cold here last night sure am glad tonight it will not be cold in house. Turkey day in a cold house -oh how i do not want to even consider that.
    So thankful thanksgiving to one an all.

  6. #6
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    Default Re: programable thermostat defective?

    Quote Originally Posted by Timothy Miller View Post
    Howdy thanks for the info.
    I did check the batteries and got a replacement digital thermostat and it working. Am concerned that the temp is a few degrees less then what the programed temp is. so programed to be 70* but temp at 68* would of thought at 68 it would turn on the furnace?
    As record cold here last night sure am glad tonight it will not be cold in house. Turkey day in a cold house -oh how i do not want to even consider that.
    So thankful thanksgiving to one an all.
    Look to see if there's instructions for calibrating the display temperature; some thermostats can be adjusted.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  7. #7
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    Default Re: programable thermostat defective?

    Quote Originally Posted by Timothy Miller View Post
    Howdy thanks for the info.
    I did check the batteries and got a replacement digital thermostat and it working. As record cold here last night sure am glad tonight it will not be cold in house. Turkey day in a cold house -oh how i do not want to even consider that.
    So thankful thanksgiving to one an all.
    Timothy --- glad you're back up and running.

    Am concerned that the temp is a few degrees less then what the programed temp is. so programed to be 70* but temp at 68* would of thought at 68 it would turn on the furnace?
    I'll throw out something I learned a long long time ago that might explain this.

    The digital thermostats come out of the box with a default program.
    Depending on brand and how sophisticated they are ---- the majority that I've seen currently have a heat temperature setting of 68 degrees and 78 for cooling as the default.


    When you p-o-w-e-r up the digital thermostat for the first time generally you will see :

    the clock at 12:00 A.M ---

    day is Monday --

    current temp. of the space.

    When you began your programming you probably noticed 68 degrees which you probably changed to 70 degrees.

    After you finished your programming and set the thermostat to " run " you were expecting it to immediately engage the heat cycle to bring the temperature to 70.

    This is the part I found out --- depending on the instructions you get they may or may not explain ---

    NOTE : The thermostat program will NOT take effect immediately after programming of your thermostat but at the next programmed time/temperature change.
    The thermostat is pre-set to 68 degrees F for heat and 78 degrees F for air conditioning.
    So, if you want a temperature other than 68 degrees ( heat ) or 78 degrees ( cooling ) right away , use the temporary override feature to enter your desired temperature setting.

    When your program becomes effective at the next time/temperature setting, the appropriate corresponding program number will appear on the display.

    In other words --- lets say , you programmed the thermostat --- for example --

    Weekday Program ( Mon - Fri )

    program 1 -- 6:00AM -- 70 F

    program 2 -- 8:30AM -- 60 F

    program 3 -- 4:00PM -- 70 F

    program 4 -- 11:00PM -- 60 F


    Now it's Wednesday at 5:30PM and you have just installed the thermostat and finished entering the above programs.

    The automatic programming doesn't engage until the first programmed time/temperature is reached --- which in the example would be 11:00PM

    The thermostat will only provide the temperature of 68 degrees F ( it's default program ) even though you programmed the temperature to be 70 F.
    In the mean time you would need to use the manual override feature to increase the temperature cutoff until the programming starts it's auto function at 11:00PM.

    Since 11:00PM is the first time/temperature setpoint ( in this case ) is when the auto programming will engage. From that point on the thermostat will follow the programming and supply the correct temperatures --- which you notice after 11:00PM.
    So, during the night the temperature will be down to 60 F and when you get up at 6:00AM the heat will be on and shutting off temperature at 70 degrees F.


    Again -- Depending on brand and how sophisticated they are ---- the majority that I've seen work this way.



    As for the current displayed temperature of the space ---The thermostats are calibrated at the factory , if you feel it doesn't coinincide with your old thermostat's display them some ( not all ) have provisions to alter that by a maximum of around + / - 4 degrees. But who's to say the other one was correct.


    Happy Thanksgiving to our neighbours down South
    "" an ounce of perception -- a pound of obscure "
    - Rush

  8. #8
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    Default Re: programable thermostat defective?

    Howdy fellers and happy thanksgiving.
    *** the help from others based on their learning an experience & insight = goodness- gratefulness that is felt by those in need and now helped- this is what started Turkey day.


    Furnace and my lack of knowledge... The temp this morn not at 70 but at 64. several cycles since i porgramed it. I notice the fan runs a little but not hot air then shuts off. Again reread the directions and just upped the temp to 75 this according to the instructions should make the furnace turn on and go up to 75 for two hours . Time will tell.
    Feeling way over my head now its about time to call a furnace guy?

  9. #9
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    Default Re: programable thermostat defective?

    Quote Originally Posted by Timothy Miller View Post
    Howdy fellers and happy thanksgiving.
    *** the help from others based on their learning an experience & insight = goodness- gratefulness that is felt by those in need and now helped- this is what started Turkey day.


    Furnace and my lack of knowledge... The temp this morn not at 70 but at 64. several cycles since i porgramed it. I notice the fan runs a little but not hot air then shuts off. Again reread the directions and just upped the temp to 75 this according to the instructions should make the furnace turn on and go up to 75 for two hours . Time will tell.
    Feeling way over my head now its about time to call a furnace guy?
    Ahhh --- so you're not up and running -- yet.

    To be honest I'm always skeptical about fixing HVAC equipment by replacing the thermostat -- not saying it doesn't happen, but , I haven't seen a fault with thermostats , usually it's something else.

    Anyway , on to the problem at hand --- seems to be a coincidence with the problem of the furnace after replacing the stat ? --- or has this shown up before replacing the stat ? ---- or is this reason for replacing the stat in the first place ?

    What type of furnace do you have ? ------- not the brand and model rather if it is a more recent type of furnace that is a 24 volt system with a control module , interlocks , etc. .
    "" an ounce of perception -- a pound of obscure "
    - Rush

  10. #10
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    Default Re: programable thermostat defective?

    We use a Braeburn and once in a while while my wife is cleaning she bumps the Hold button that over rides the program. I can usually tell be waking up in the middle of the night sweating, as the others say there may be a way to override, check and see if you have that hold button or something similar

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