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  1. #14
    Join Date
    Jan 2007
    Location
    Coloma MI
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    214
    Quote Originally Posted by garya505 View Post
    Too bad even the high-end stats don't have a feature like this. Seems like it wouldn't be to difficult to do in software in a stat.
    I made that a few other suggestions to the Lennox Tech I spoke with. My sales guy also sent the suggestions to his rep at Lennox only because 5 other customers had the same suggestions. I've also posted them here so hopefully someone in R&D at Lennox will see them. Maybe they will incorporate some of them in the next version of firmware.

    There are many utilities out there providing the on-peak/off-peak option now and that was the biggest reason I went with the dual fuel. I run the gas during the day and HP at night. Gas costs me .92 a therm, off peak HP costs .41 a therm at my 25 deg cutout point. Above that it's even cheaper.
    Last edited by SJProwler; 01-17-2011 at 09:01 PM. Reason: spelling...

  2. #15
    Join Date
    Aug 2010
    Location
    Monroe County, PA
    Posts
    99
    Quote Originally Posted by garya505 View Post
    Too bad even the high-end stats don't have a feature like this. Seems like it wouldn't be to difficult to do in software in a stat.
    If anyone does know of a thermostat that supports this feature, I'd be up for investing in it. I always prefer to use equipment as it was designed instead of kluging it.

  3. #16
    Join Date
    Jun 2009
    Location
    Albuquerque NM
    Posts
    2,485
    Quote Originally Posted by Tom Campbell View Post
    I did a quick test to see what would happen if I tried setting the HW IAQ to think it had an outdoor sensor even though none was attached (infinite resistance) - in hopes that it would just ignore it (setting 342). That would have allowed me to just hook up the resistor on a timer and leave it open other times. No luck. It throws an error 53 and flashes on and off obnoxiously, so I'll have to either use a relay to toggle between 2 different resistors (high temp and low temp) or install an actual HW outdoor sensor and toggle between it and the 100K resistor. It may be another week before I get the time to pick up parts and give it a try.
    I thought you would just put the resister in series with the sensor, then short out the resistor when you want the HP to be enabled.

  4. #17
    Join Date
    Jun 2009
    Location
    Albuquerque NM
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    2,485
    Could probably be done with a stat that has dry contact outputs that can be programmed by time-of-day.

  5. #18
    Join Date
    Aug 2010
    Location
    Monroe County, PA
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    99
    Quote Originally Posted by garya505 View Post
    I thought you would just put the resister in series with the sensor, then short out the resistor when you want the HP to be enabled.

    Resistors in series are cumulative, so if I use it with the actual sensor it could produce some "off the charts" resistance levels that the t-stat wouldn't recognize - and throw another error.

    http://hades.mech.northwestern.edu/i..._resistors.gif

    Edit - Although now that I think about it, I could do a 25K and 75K in series and short out the 75 when I want to operate in standard mode (25K = 34 degrees)

  6. #19
    Join Date
    Jun 2009
    Location
    Albuquerque NM
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    2,485
    Quote Originally Posted by Tom Campbell View Post
    Resistors in series are cumulative, so it could produce some "off the charts" resistance levels that the t-stat wouldn't recognize - and throw another error. Better to just use a relay that will toggle between the two.

    http://hades.mech.northwestern.edu/i..._resistors.gif
    I guess I didn't explain.

    If the switch is used to short the added resistor (i.e. in parallel with the resistor), and the switch closes when you want the HP to be enabled ...

    Switch open - HP disabled
    When the switch is open, the resistance of the added resistor is added to the reistance of the sensor. That's why I suggested 50k, it keeps you on the chart, at least down to about 0F.

    Switch closed - HP enabled
    When the switch is closed, there is no added resistance from the resistor, so the only resistance is in the sensor. It's like there is no added resistor there at all.

    Of course, switching between the 100k and the sensor would work too, but might require a little more hardware.

  7. #20
    Join Date
    Aug 2010
    Location
    Monroe County, PA
    Posts
    99
    Quote Originally Posted by garya505 View Post

    Switch open - HP disabled
    When the switch is open, the resistance of the added resistor is added to the reistance of the sensor. That's why I suggested 50k, it keeps you on the chart, at least down to about 0F.

    Switch closed - HP enabled
    When the switch is closed, there is no added resistance from the resistor, so the only resistance is in the sensor. It's like there is no added resistor there at all.
    I understand the logic now. That should work as well.

  8. #21
    Join Date
    Dec 2006
    Location
    Just South of Indianapolis
    Posts
    17
    Hook a timer and relay to connect the yellow wire to the white wire out side causing the heat banks to run at the same time as the heatpump. and connect a normaly closed relay connected to the orange to prevent this from summer time heating.

  9. #22
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,756
    How about a space heater for the bedroom?
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  10. #23
    Join Date
    Aug 2009
    Posts
    2,459
    Sounds like you need a programmable controller. I'm sure there are guys on the controls board who live in your area and sell such things.

    I've got all kinds of crazy things automated at my place and I can view and modify everything over the net. That's probably overkill for you but it's pretty standard stuff for HVAC controls folks.

  11. #24
    Join Date
    Jun 2009
    Location
    Albuquerque NM
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    2,485
    Quote Originally Posted by BACnet View Post
    Sounds like you need a programmable controller. I'm sure there are guys on the controls board who live in your area and sell such things.

    I've got all kinds of crazy things automated at my place and I can view and modify everything over the net. That's probably overkill for you but it's pretty standard stuff for HVAC controls folks.
    Can you check how much beer you have in the fridge over the net, so you know if you should stop at the store on the way home from work?

  12. #25
    Join Date
    Aug 2009
    Posts
    2,459
    Quote Originally Posted by garya505 View Post
    Can you check how much beer you have in the fridge over the net, so you know if you should stop at the store on the way home from work?
    That's a trick question, right? There's never enough beer in the fridge- it's always a good idea to buy more on the way home each night!

  13. #26
    Join Date
    Aug 2010
    Location
    Monroe County, PA
    Posts
    99
    Quote Originally Posted by BACnet View Post
    Sounds like you need a programmable controller. I'm sure there are guys on the controls board who live in your area and sell such things.

    I've got all kinds of crazy things automated at my place and I can view and modify everything over the net. That's probably overkill for you but it's pretty standard stuff for HVAC controls folks.
    That's a cool idea about having a custom thermostat solution built - I knew there was a whole industry to support that kind of thing for commercial and home theater stuff. I never considered going that far for my residential interest though.

    If there's an over-the-counter residential thermostat that would include the aux heat setting in the 7-day programming, that would do the trick, but so far I can't find one. I just can't see paying $4-500 for a custom built and programmed solution though - for that much I might as well just run in resistance heat all the time for the next 3 years.

    Being a computer geek I love automation - my last house had all the lighting tied in with the security and I could control it all by one computer (but not over the net - it was using older tech). I've also done a fair bit of circuit board work in the past - particularly resurrecting old pinball machines that have blown diodes, triacs and all sorts of high and low-voltage circuitry. So I'm not opposed to or scared of having something custom built, I just can't justify the cost in both materials and professional services time.

    And so I'll go with the resistor idea in conjunction with a used battery operated programmable thermostat with a dry-contact design (not for the temp aspect, just to open and close the circuit by time of day - cheaper than buying a 120V timer and transformer). Not sure if I'll add a DPDT relay to toggle between resistors or just follow gary's recommendation to short out the high resistor when I want to operate in normal heatpump mode. (Probably the latter to start)

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