Installation wiring

[FastDr]

Hello:

My original thermostats are Rodgers-White (Model 1F80-261).  Photo attached. I successfully installed the Nest Learning Thermostat on the main floor.  It works perfectly.  Photo attached. 

I need help with the upper level which has a master and slave configuration (I believe?).  The primary/main thermostat has a Blue and Orange wire in addition to the Red, White, Green and Yellow wires. The secondary/slave thermostat has White, Yellow, and Red wires only.  Both have jumper wires.  I would like to replace just the primary/main with the Learning Thermostat.  Photos attached.

Hoping you can help.

Original ThermostatOriginal Thermostat model numberFirst Floor Nest installationSecond Floor main thermostatSecond Floor slave thermostat

[CoolingWizard · Accepted solution]

[CoolingWizard]

FastDR,

there cannot be two thermostats controlling one system. What you can have is one system as a heat pump and the second system is not a heat pump. The wire that’s connected to the O terminal is the heat pump system. The second thermostat controls and AC system with a furnace.  The only other possibility is you have a zone controlled HVAC system. 

Ken, The AC Cooling Wizard

[FastDr]

Thanks so much for your prompt response.  We only have a single system for the entire house.  The heat is an oil fired boiler.  We have traditional air conditioning.  The distribution is via hydro air. So does it sounds like we have a zone controlled HVAC system?  If so, will the Nest work on this zone and how would I wire?

[CoolingWizard]

Some zone controllers are very compatible with thermostats and some use a proprietary communication system. The odd thing is that thermostat which has a wire on the O terminal is definitely a heat pump type system. Heat pumps use a four-way reversing valve that changes the direction of the flow of the refrigerant to make it change from air-conditioning mode to heating mode., the mode switch is controlled by the O wire when the O wire is energized with 24 V AC current, the valve switches, and it changes modes. 

The only other explanation is it the HVAC tech hooked up the orange wire to the O terminal, but there is no heat pump.

Ken

[FastDr]

Here are additional photos from the main panel located in the basement air handler for the main level and basement zones and the panel on the upstairs air handler for that zone (primary/slave).  Not sure they help, but hopeful.

Basement panelBasement panel_2Basement panel_3Second Floor panel

[CoolingWizard]

Hello FastDR,

yes indeed you have two separate zone controllers. The NCM 300 supports up to three zones dampers and up to three controlling thermostats. Your NCM 300 is utilizing two controller thermostats and two motor driven dampers.  
The second zone controller is an EWC-ST-2E and it supports two zone dampers and 2 controlling thermostats. What I am trying to figure out is if the two are interconnected with each other.  
basically, he’s on controller sits between the thermostat and the HVAC equipment and integrate the operation of dampers to open and close zones. 

Since you have a single system, and there are two independent zone controllers and that is not a typical configuration. Normally the two zone controllers would be interconnected and these two are not.  

Ken, The AC Cooling Wizard

[FastDr]

Hello Ken:  

I so very much appreciate you putting your head on this.  I had no idea these things could be so complicated.  Now i know. If you come up with anything, please let me know!

Otherwise, have a happy holiday season, CoolingWizard! 

FastDr

[CoolingWizard]

I am going to make some annotations on your photos and post them back here.  

Ken

[FastDr]

Okay. Will be on the look out!

FastDr (AKA Ed)

[CoolingWizard · Accepted solution]

[FastDr]

Hi Ken:

I will definitely be filing these annotated photos.  It makes a lot more sense to me now.  Still, hopeful I can make the Nest work, with your help of course.  The blue and the orange wires need to be located on the Nest (?O/B and C).  

Thanks again for all your help with this install!!

Ed

[CoolingWizard]

From the standpoint of a thermostat, it does not know that there are zone controllers in the system. All the thermostat does is provide the function of either calling for heat or calling for cooling depending on your settings within your thermostat. So as long as your nest is wired the same way as your old thermostat was wired, colored wire to the same color and label screw for example it will work just fine. 

[FastDr]

Great!  However, I am still confused about where to place the orange and blue wires. I am not sure which of these two is to be placed on the "C" terminal of the Nest thermostat. 

[CoolingWizard · Accepted solution]

Since you, as you stated, you do not have a Heat Pump system, you will not need to connect the Orange wire on O nor the wire connected to B. Your thermostat is manufactured by White Rogers and it uses the O and B for heat pumps only.  You currently do not have a common wire at either thermostat as well. 
Ken, The AC Cooling Wizard

[FastDr]

Got it!  Thanks a million Ken!!

Best,

Ed

[FastDr]

Hello again Ken:

I connected the thermostat attaching just the four wires (red, yellow, green, and white). Unfortunately, it works initially as I was able to complete set up, but get an error message after a few minutes regarding power (E15 within an orange circle on the thermostat screen) and a suggested online link (nest.com/e80).  I disconnected and charged it up with a USB cable, but the same problem occurs after a few minutes after remounting it.  Any ideas? External power source?

Thanks as always!

[CoolingWizard]

Your thermostat connects to the digital control board, and as a result, it cannot use the so-called back door charging method that the Nest third generation can do. What you need to do is check to see if behind the wall you have an extra wire not connected at your thermostat. If you do, we will connect it to the common side of the transformer and we able to charge your thermostat that way. 

Ken

[FastDr]

Yes, there are two free wires that run between the thermostat and control panel.

[CoolingWizard]

FastDR,

do you need to pick one of the two free wires, hopefully blue is one of them, and then attach it to the seat terminal of the thermostat. Then you need to go to the other end of the cable and find it the same color, blue for example, and you need to attach it to the common side of the power transformer. How to do this you’re going to have to do a little work, if you look at the orange and blue wire cable that comes into the zone controller, that goes to your main unit power transformer you need to follow that cable open that panel and take a look. And here comes the tricky part. One of the two wires coming off of the transformer is going to be routed to all the devices inside that HVAC air handler. And one wire is only connected. Going out of the unit on a cable. The one that is attached from the transformer to all the other devices is indeed the common one and that’s where you attach your blue wire , so one of the two wires coming from there the orange in the blue is going to be the common and that’s where you will put your blue common. I hope this makes sense. 

Ken, The AC Cooling Wizard

[FastDr]

Hello Ken:

Well, the good news is the Nest is connected, getting power, and passed the tests performed by it.  I was able to program it and all is well there.  The bad news is now I cannot seem to get the other thermostat (labeled thermostat 2) connected to the second floor panel (EWC-ST-2E) to work.  You were crystal clear about the non function/need for the blue and orange wires (no heat pump) so they are not connected to the Nest.  I did not use either of those two for the common connection either.  As you saw in my original photos those wires were connected to the main controlling thermostat (labeled thermostat 1).  I have two other wires (tan and black), one of which I used for the common connection and left the blue and orange wires alone.  You're response was a little confusing, so I may have missed something along the way. 

[CoolingWizard]

I am so sorry for any confusion I have caused you.  The effort I was trying to clear up was how to get the common wire to your thermostat. Now it would’ve been easy to hook it up to either the blue or the orange wire that is currently on the control board of the zone controller. What I did not know was which of those wires was hooked up as common and which one was hooked up as line power. That is why I suggested following that cable. Back to the HVAC unit and find out which one was power and which one was common. We call the neutral side of the transformer as Common, it is common because that wire is connected to all of the relays and electrical contacters.  Hence it is is common to all components.  The Power IN side is sent independently to the electrical components as they are called for.  Such as the Blower relay. 

Do you have a Volt Ohm Meter some time called. Multimeter?

Ken, The AC Cooling Wizard

[CoolingWizard]

FastDR,

I took time to read the EWC documentation on the ST-2E control board.  Unfortunately, that board requires a thermostat with both an O and a B sub base. In order to activate the Heating the thermostat must connect R to B and to R to W. To activate for cooling the thermostat must connect R to O and R to Y and G.  The upgraded model is the that replaces the ST-2E is the NCM-300.  The upgrade was brought since thermostat makers were discontinuing the use of both B and O and combining that on a single O/B terminal.  So, sadly, that zone controller ST-2E is not compatible with any current day programable thermostat including the Nest.  Your current options are to upgrade the ST-2E to an NCM-300, or to reinstall the old thermostat.

Ken, The AC Cooling Wizard

[FastDr]

Hi Ken:

Too bad.

Yes, my concern was the disconnected blue and orange wires.  

At any rate, I learned a LOT.  

Thanks for your time and patience.

Best,

Ed

[FastDr]

Hey Ken:

I found what looks like an accurate YouTube video on changing the ST-2E with the NCM-300. It looks reasonably straight forward.  I know I have been a pain, but could you take a look and let me know what you think?  I would, as always, be most appreciative!

https://www.youtube.com/watch?v=pqDAymD3c-A

Ed

Ed

[CoolingWizard]

While the YouTube article you sent me is ok, I feel that anyone that can follow the EWC technical bulletin can make this swap out. Make sure you turn off the power to the air handler before you start the upgrade. 

Ken. The AC Cooling Wizard

[FastDr]

Yes, The link to the manual and the technical bulletin were below the video.  Pretty sure I can get it done.  Will order it and try the swap...after it warms up!  LOL

Thanks!

Have a wonderful holiday season!!

Ed

[Markjosephp]

Hello there,

I wanted to ensure that everything was covered here.

Thanks for helping, Ken.

@FastDr, I hope you've got the answer you're looking for. If you're still in need of assistance, feel free to let us know.

Regards,

Maek

[Markjosephp]

Hello FastDr,

I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Thanks,

Mark

[Markjosephp]

Hi FastDr,

I'm checking in to make sure that you've seen my response. Please let us know if you have any additional questions or concerns before we lock this thread in 24 hours.

Thanks,

Mark

[FastDr]

Thanks so very much for checking in with me.  I am very close to finalizing a plan for the setup here at my home.  I do have additional questions.  The holiday season set me back timewise, but will re-engage this week.

Thanks again!

Fast Dr

[Markjosephp]

Hey there,

Thanks for getting back to us, @FastDr. I'm sure that you might have additional questions with the installation, and we would be glad to know what the result is. No worries! I'll leave the thread open for a few more days, and don't hesitate to give us a shout if you need more help.

Regards,

Mark

[FastDr]

Thanks a million Mark!  You guys have been terrific!!

Best,

FastDr

[Jake]

Hey there,

Sorry for the late reply. I wanted to follow up and see if I could be of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further. 

Best regards,
Jake

[FastDr]

Hello Jake:

Below are my final questions for my installation of my second Nest.  I sent this to Ken, but he was not able to respond.  Can you see the entire string between myself and Ken? Here they are:

........I am very close to finalizing the plan to swap out the ST-2E with the NCM-300. I am confident I can de-energize the panel/air handler and have a voltmeter to be sure it is disconnected to power.

My questions:

• Do I need to change the position of any of the dip switches on the existing NCM-300 in the basement to enable the conversion to the second NCM-300 for the Nest on the upper level?  
• Do I connect the O and B wires to the new NCM-300? I suspect I do not.

Meanwhile, It appears the new NCM-300 (upper level) will already be configured for our setup.  

Thanks so very much in advance as usual.

Best,

Ed 

[FastDr]

Hello Ken:

I am hopeful you had a wonderful holiday season.

I am very close to finalizing the plan to swap out the ST-2E with the NCM-300. I am confident I can de-energize the panel/air handler and have a voltmeter to be sure it is disconnected to power.

My questions:

• Do I need to change the position of any of the dip switches on the existing NCM-300 in the basement to enable the conversion to the second NCM-300 for the Nest on the upper level?  
• Do I connect the O and B wires to the new NCM-300? I suspect I do not.

Meanwhile, It appears the new NCM-300 (upper level) will already be configured for our setup.  

Thanks so very much in advance as usual.

Best,

Ed 

[CoolingWizard]

I am sorry I did not respond to you more quickly. The NCM – 300 is designed as a direct replacement for the older model, and in fact in the instruction packet that comes with it are the very step-by-step procedures, and how you transition from the older model to the NCM 300. The reversing valve on the NCM-300 is the W1 terminal the wire should be connected there. 

The AC Cooling Wizard

[FastDr]

No worries for the delay. Wonderful!  All set! Thanks for all the time you took to walk me through this! It is much, much appreciated!!

[Jake]

Hey there,

Thanks for the help CoolingWizard.

I am glad to hear everything is good to go from here. With that being the case, I am going to go ahead and lock the thread in 24 hours. Please let me know if you have any further questions from here, as I would be happy to review.

Best regards,

Jake