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R, G, C, Y, W, and */OB Nest thermostat for 2 stage heating

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tamer
tamer Member Posts: 28
edited April 2023 in Thermostats and Controls
I recently also bought a Nest thermostat--to be clear, it's NOT the learning thermostat, so it has 6 total terminal connections on the baseplate--R, G, C, Y, W, and */OB.

I installed a new Bosch two-stage furnace. The previous thermostat did not support two-stage heating, thus the upgrade to the Nest. All wires were hooked up as they were on the old thermostat, with an additional wire for W2(2nd stage heat) on the furnace control board connected to the */OB terminal on the Nest. After wiring and going through the setup on my phone, the thermostat turns on the AC when calling for heat. Obviously this isn't what we want! It appears the thermostat thinks there is a heat pump installed.

My question is :
Is there a way to configure the */OB terminal for 2nd stage heat? So I don't have to buy new thermostat. Thanks

Comments

  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
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    It’s in the equipment menu for Gen 3 thermostats 
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • tamer
    tamer Member Posts: 28
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    It’s in the equipment menu for Gen 3 thermostats 

    @Robert O'Brien so is it design to have the option to use */OB terminal for 2nd stage heat? The one I have is this one https://www.homedepot.com/p/Google-Nest-Thermostat-Smart-Programmable-Wi-Fi-Thermostat-Snow-GA01334-US/314573006 . Is this the 3rd gen? Thanks
  • HVACNUT
    HVACNUT Member Posts: 5,863
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    Unfortunately you need to download the Google app for the installation instructions. 
    I have no idea whether or not *OB is for a second stage. What I can tell you is that typically, a 2 stage thermostat will  have W1,W2,Y1,Y2. The OB terminal is to energize the reversing valve in a heat pump on cooling (O) or heating (B).
    I bet that diabolical * has something to to with it.
  • unclejohn
    unclejohn Member Posts: 1,833
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    Did the Nest ever ask you if you had a Air Conditioner or Heat Pimp. If not you did not get into the correct set up menu
  • pecmsg
    pecmsg Member Posts: 4,883
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    Worst T-Stat you could have chosen!
    SuperTech
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,068
    edited April 2023
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    Ignore the Naysayers that tell you that the NEST is junk. They are the folks that were unable to get the technology to do what they wanted it to do. Or perhaps a customer of theirs installed one and they were unable to operate the equipment properly during a service call for some other problem and just blamed the NEST for their inability to cope with technology.
    tamer said:


    My question is :
    Is there a way to configure the */OB terminal for 2nd stage heat? So I don't have to buy new thermostat. Thanks

    NO. There is no way to make the */OB of any Next thermostat into a W2 terminal. You needed to purchase the Nest thermostat with two stage capabilities. There must be a W2 terminal on any thermostat you use in order to do what you want.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    tamerSuperTech
  • pecmsg
    pecmsg Member Posts: 4,883
    edited April 2023
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    They do make a good hockey puck. 
    Also really good for skeet shooting! :)


    EdTheHeaterManSuperTech
  • SuperTech
    SuperTech Member Posts: 2,186
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    Ignore the Naysayers that tell you that the NEST is junk. They are the folks that were unable to get the technology to do what they wanted it to do. Or perhaps a customer of theirs installed one and they were unable to operate the equipment properly during a service call for some other problem and just blamed the NEST for their inability to cope with technology.
    My question is : Is there a way to configure the */OB terminal for 2nd stage heat? So I don't have to buy new thermostat. Thanks
    NO. There is no way to make the */OB of any Next thermostat into a W2 terminal. You needed to purchase the Nest thermostat with two stage capabilities. There must be a W2 terminal on any thermostat you use in order to do what you want.
    @EdTheHeaterMan I work for a company that is unfortunately a Nest dealer. I can say from years of experience that they are not a good product.  We see more problems with Nests than all other thermostats combined.  For example, we had a customer with Nest learning thermostats on two dual fuel systems. The 2nd floor system liked to automatically revert being set as a single stage hear pump with electric auxiliary heat. Customer had us install Honeywell thermostats, no further problems. @pecmsg is 100 percent right about them. 
    STEVEusaPA
  • pecmsg
    pecmsg Member Posts: 4,883
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    SuperTech said:
    Ignore the Naysayers that tell you that the NEST is junk. They are the folks that were unable to get the technology to do what they wanted it to do. Or perhaps a customer of theirs installed one and they were unable to operate the equipment properly during a service call for some other problem and just blamed the NEST for their inability to cope with technology.
    My question is : Is there a way to configure the */OB terminal for 2nd stage heat? So I don't have to buy new thermostat. Thanks
    NO. There is no way to make the */OB of any Next thermostat into a W2 terminal. You needed to purchase the Nest thermostat with two stage capabilities. There must be a W2 terminal on any thermostat you use in order to do what you want.
    @EdTheHeaterMan I work for a company that is unfortunately a Nest dealer. I can say from years of experience that they are not a good product.  We see more problems with Nests than all other thermostats combined.  For example, we had a customer with Nest learning thermostats on two dual fuel systems. The 2nd floor system liked to automatically revert being set as a single stage hear pump with electric auxiliary heat. Customer had us install Honeywell thermostats, no further problems. @pecmsg is 100 percent right about them. 
    I don’t take pleasure in this. Just the truth!
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,068
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    @SuperTech I too was a Nest Pro dealer for the thermostat that you have so much trouble with. You just need to know your limitations. Out of every Nest thermostat you worked on there was a problem thermostat on every job? And that ONE thermostat example was on something other than a standard system. The dual fuel system is the one with the problem. Have you ever had a different problem on a dual fuel system that was not related to the thermostat? I know that I have had customers with dual fuel systems that used other thermostats. When the techs that worked for me were unable to resolve the problem, I would spend some time on the job with several sets of instructions. I would figure out how the heat pump, the gas valve, the thermostat and the optional kit sometimes, all would work together. I was not throwing NEST thermostats away since there were none. I also did this with Oil Heat dual fuel systems. The Nest is not always the cause of the issue but it is a good scapegoat.

    The fact that the nest does not use contacts to make and break circuits is part of the understanding of the problems. Everyone wants to fix it based on what they think the problem should be, not on what the compatibility of all the working parts are. Some controls are just not compatible with the NEST circuitry. That is what isolation relays are all about. I remember placing 6 different isolation relays on a 2 zone system in order to make two Nest thermostats work on a McMansion in Cape May. There were 5 zones on 4 condensing units and Unico air handlers with Hydro coils for heating. 4 thermostats worked perfectly. One of the two that operated the zone panel for the first floor and basement air handler would have intermittent failures. I could not get it to work flawlessly as designed. The homeowner wanted NEST because it worked in his other property and his business property. He did not want to have a second WiFi format for the Shore house. I had to make it work.

    The best way was to have the NEST operate 3 different RIB relays (HEAT, COOL, and FAN) for the thermostats on the zone panel. That was a total of 6 RIB relays. Since the Nest switching protocol was not actually relay contacts, the Zone panel did not get the proper signal EVERY time causing nuisance failures on heat and sometimes on cool. By making the NEST operate a relay with real contacts, the zone panel understood the call for heat, cool and fan everytime. You just need to understand the limitations.

    Or you can just use them as a hockey puck
    . When I hear that, all I can think of is the Deadmen installing boilers with steel pipe, and telling the younger boiler fitters that this copper pipe thing will never catch on. I learned boiler piping from one of those old-timers. He finally gave in and used copper pipes by the time I was an apprentice.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    GGross
  • lost11
    lost11 Member Posts: 37
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    pecmsg said:

    Worst T-Stat you could have chosen!

    what would you suggest? Ecobee any better? Or Honeywell's T9?
  • lost11
    lost11 Member Posts: 37
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    That is what isolation relays are all about. I remember placing 6 different isolation relays on a 2 zone system in order to make two Nest thermostats work on a McMansion in Cape May. There were 5 zones on 4 condensing units and Unico air handlers with Hydro coils for heating. 4 thermostats worked perfectly. One of the two that operated the zone panel for the first floor and basement air handler would have intermittent failures. I could not get it to work flawlessly as designed. The homeowner wanted NEST because it worked in his other property and his business property. He did not want to have a second WiFi format for the Shore house. I had to make it work.

    Or are isolating relays used to provide the power to your smart thermostat with 3/4 wires and sending only 2 wires to the switching relay? Most switching relay companies won't just install a larger or a second transformer in case someone wanted to use a smart thermostat.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,068
    edited April 2023
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    pecmsg said:

    Worst T-Stat you could have chosen! @lost11 asked What would you recommend?

    Good Question. The anti Nester should certainly have a smart thermostat that they might recommend. unless they are recommending that you not have WiFi access at all.

    I love this discussion, It gets everyone's passions to to peak on to one side or the other!
    (says the old fart stirring the pot)
    Mr. Ed

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • pecmsg
    pecmsg Member Posts: 4,883
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    lost11 said:
    Worst T-Stat you could have chosen!
    what would you suggest? Ecobee any better? Or Honeywell's T9?
    I used to like the Honeywell. Since separating residential and commercial I don’t know. 

    I here good things about ecobee
  • SuperTech
    SuperTech Member Posts: 2,186
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    I don't see problems with all of the Nest thermostats, just more issues with them than others.

    I've only had one EcoBee go bad for a customer over the years, they seem to be pretty good. I prefer the Honeywell WiFi thermostats, T6 pro, T9, Vision Pro IAQ are all good thermostats.

    @EdTheHeaterMan that's a creative solution that you came up with, I can picture one of my apprentices coming across that and cursing me out for doing something like that, but you gotta get it to work one way or another. 
    STEVEusaPAEdTheHeaterMan
  • lost11
    lost11 Member Posts: 37
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    SuperTech said:

    I don't see problems with all of the Nest thermostats, just more issues with them than others.

    I've only had one EcoBee go bad for a customer over the years, they seem to be pretty good. I prefer the Honeywell WiFi thermostats, T6 pro, T9, Vision Pro IAQ are all good thermostats.

    @EdTheHeaterMan that's a creative solution that you came up with, I can picture one of my apprentices coming across that and cursing me out for doing something like that, but you gotta get it to work one way or another. 

    I don't really like the whole idea of Nest "learning" thermostat. It can take me a few minutes to program my week's setting, versus the Nest having to adjust it to let it learn. Does Google need more information about me? LOL

    I was learning towards the T9 coupled with a few sensors.
    SuperTech