Braeburn 1000 to NEST with a HVAC Coil sitting on top of the air handler and multi-zones

[smumur]

Hello, 

I have a complicated system in the house. We bought it as is and the old Braeburn thermostats died and I am struggling installing the NEST learning thermostat. Below are the pictures of the old thermostat wiring and the zone control boards wiring...is anybody familiar with this situation? Can you tell me what i need to do here? 

I tried wiring everything but O and B wires are causing an issue, i believe, the board start clicking whenever i test the system and not sure if it should be opening the valves or closing it...i feel like it gets the fan signal and cooling signal at the same time maybe??? Any help is much appreciated...

[CoolingWizard]

@smumur ,

The Model ST Series Panels Are For Single Stage Heating and Cooling with Manual Changeover. Zone 1 Is The "Master" Zone Which Controls The Heating and Cooling Mode and Also The Fan Operation.
The ST-2 Is a 2 Zone Panel. Zone 2 Will only operate In the same system mode that ehe Zone 1 Thermostat Is In. Each Thermostat Can Turn The System "On" and "Off ", But Only In The Same Mode. Frankly, This is not a  very sophisticated zone controller.  It does not handle heat pumps very well.  

The pictures of your two thermostats look the be the same thermostat. If you look at the ST thermostat zones terminal block, the Zone 1 TSTAT is the controlling thermostat, it has Y,W,G, R1 and O.  The R of thermostat is connected to the R1. The white O wire of thermostat 1 is connected to O of the block as is blue Common and the Green Fan. 

Your ST zone controller is not wired correctly.  On the TSTAT-1 block there are two connections for a heat pump, the B and the O. there should not be a wire on both. Your heat pump is either and O model or a B model. That blue wire on B needs to be on the C at the top of the Zone1 TSTAT block. The white wire attached to W needs to be on the Nest Learning Thermostat W2/AUX.  This is your Auxiliary Heat. At thermostat 1, the second white wire goes to the O/B. 

Now one of the cables on the right side has a white and a blue wire wrapped around the outer sheath. Unwrap the blue wire and attach it to the ZONE2 TSTAT C connector. This will bring COMMON to the zone 2 Nest thermostat. Whichever thermostat is ZONE2, will only have R,C,Y,W wires attached.  It should be set up as a forced air, electric heat.  Zone 1 thermostat will be set up as a heat pump with auxiliary heat. Your wires should be R, C, Y, G, W2, OB.

I hope this helps

AC Cooling Wizard

[smumur]

Wow...amazing knowledge. Thank you very much AC Cooling Wizard...

Here is a bit more information...i just want to make sure that you have the whole picture before i stary making the changes. if what you explained above will still apply, then i will make sure to change wiring right away. thank you very much again. 

I dont have a heat pump, it is Bryant air handler unit with a furnace coil on top of it. Attaching pictures of the products and their wiring diagrams.

Also, i apologize for the confusion, i sent the same wiring twice for the main zone, the second thermostat wiring is attached now correctly. air handler modelfurnace coil modelair handler wiring diagramcondensing unit/ ACAC wiring diagramzone 2 thermostat

[smumur]

Also, R1 that you mentioned about...is that Rh or Rc on the Nest unit? Thank you!

[CoolingWizard]

@smumur ,

According to that manual, you have a Air Conditioning Condensing unit and not a heat pump. So, the questions now arises why does TSTAT1 have a wire on the O and the W.  However,  the equipment terminal the O wires is not used which matches the American Standard Condensing Unit. The R1 is the R/Rc on the Nest Thermostat.

AC Cooling Wizard

[smumur]

I do not know but i can tell you that the cooling has been working just fine but i tried every combination of the R wire between Rh and Rc on Nest, i also moved the W2/Aux to W1 and the heat doesn't want to come on...only cooling the house, not sure how to start the heat yet...in all of these combinations, i feel like, the fan is on, just bringing outside air without cooling and then it opens both valves so it starts blowing air to the basement and main floor but not heated air, just fan...

At this point, i will probably return the Nest and get an honeywell with a professional installation service. Thank you very much for your help.

[CoolingWizard]

@smumur ,

The Nest thermostat will work, but you should hire a Nest Pro that is also a HVAC Technician.  Just need to sort out all those cables running between the different zone controllers.  

AC Cooling Wizard

[smumur]

Unfortunately, i bought the Nests with installation service but Google's sub screwed it up and didnt schedule anyone for the date/time that was confirmed. Now, they are telling me that it will be 3 to 4 weeks to schedule someone...i'd say pretty bad service...that is why i am a bit disappointed.

Regardless of their service screw up, I feel like i am getting some where. Right now, I have the red wire on Rc, Yellow on Y, White on W, Blue on C, G on Green and O is removed...

I can turn both heat and cool now...but the valves are not cooperating. O and B wires were managing the 2 valves downstairs somehow through the panel.

If you look at the panel, on the system side, O and B is not hooked up at all. So O and B is not going to the furnace or condensing unit. They doubled on Y which goes to the furnace and condensing unit, i don't know why...i am assuming, Y is turning the condensing unit on and the fan in the furnace, and W turns on the heat and automatically the fan in the furnace. G is just for fan. R is for power. 

Per your recommendation, I moved B  (blue) wire to C, which powers up the Nest unit fine with Rc.

But O wire, when it is on O/B, it doesn't allow the heat to turn on...but why??? Instead it is screwing the valve position...ugh...also regardless of if the downstairs (slave) thermostat is on or off, the valves doesn't move...i'd think that thermostat would move the valves only, just open the valve and close the valve if the heat or cool is on or off but it doesn't change state just with that thermostat...the main floor thermostat has to talk to it through the panel somehow i guess...Very weird system...more pictures if it helps.

i am happy to talk to you over the phone if you are interested in solving this mystery. Happy to Venmo you some agreed upon money if we can figure this out. 

Thank you for your help regardless...control panel system side1control panel system side2control panel thermostat side1control panel thermostat side1valves

[CoolingWizard]

@smumur ,

I wish I was physically there to help sort this out. Since both thermostats are connected to the ST zone controller, we need make sure we understand how the ST operates.  Now the thermostat connected to TSTAT1 is the master thermostat and controls the system mode albeit Heat or Cool. As I stated before, this is not a very capable zone controller. For example, to get this ST to turn on the heat, TSTAT 1 has to connect R1 to B.  This will cause the main equipment controller to energize the W on the EQUIPMENT terminal block. This action starts the heating cycle. 
For the cooling, TSTAT1 one must connect R1 to O. This will cause the main controller to energize the G and Y on the EQUIPMENT terminal block.  To make this work with a Nest, requires some special wiring.  The TSTAT1 needs to have the R1 wired to R, the Y wires is wired to the Y on the TSTAT1 block, and a jumper wire down to O. The Nest W gets wired to TSTAT1 W with a jumper down to B.  The Nest G wires goes to G on the TSTAT1 terminal block. 

Thermostat 2 needs R, W, Y, G, and C. So as stated before, unwind that blue conductor and attach it to the C on the TSTAT2 terminal block. The configuration of the Nests will be Forced Air, Gas Heat. 

AC Cooling Wizard

[zoeuvre]

Hi folks,

@smumur, thanks for reaching out, and I'm sorry to hear about the situation. I want to check if you managed to see the response above. Please let us know if you still have questions or concerns, as we'll be willing to assist you more. 
 

I appreciate your help, @CoolingWizard. 

Best,

Zoe 

[smumur]

Hello,

Thank you for checking in @zoeuvre. No, this is still not resolved...Per @CoolingWizard latest configuration, this is my understanding;

- I connect "TSTAT1 R" to "Nest Rc"

- I connect "TSTAT1 Y" to "Nest Y" then put a jumper between "Nest Y" and "Nest O"

- I connect "TSTAT1 W" to "Nest W" and then put a jumper between "Nest W" and "Nest B"

- I connect  "TSTAT G" to "Nest G"

Three questions;

- What do i do with the original "O" wire? The cream color wire? 

-The O/B terminals are the same on NEST. So should I buy different gauge (thinner) wire to squeeze 2 wires in all of these terminals?

- Initially, we moved the "TSTAT B" wire to "TSTAT C" wire so i am moving it back to "TSTAT B"?

Thank you!

[CoolingWizard]

The Y jumper to O is made at the TSTAT1 not the Nest. 
Keep in mind that the ST-2E is a pretty limited zone controller.  You would be better off upgrading to a ECOJAY Smart Zone controller.  

The EMC ST series require that only the thermostat attached to TSTAT1 can set the system mode.  That is all that the O and B wires do. This requires a very special thermostat to be used.  This O and B should not be confused with the Heat Pump OB. On most thermostats when you put the system mode switch in Heat or Cooling nothing happens. On the thermostats that are made to work with the EMC ST zone controller, when you set the thermostat to heat, it energizes the B wire. This causes the EMC ST controller to set the HVAC equipment controller to HEAT.  If the thermostat sets mode to Cooling, the thermostat will energize the O wire.

The nice thing about a smart zone controller is that any active thermostat can initiate the system mode. There is a primary thermostat, that can over ride, however, if that primary zone is not calming for heat or cooling, the other thermostat can still initiate the system mode.  

AC Cooling Wizard

[smumur]

Thank you again @CoolingWizard   

Ok. I don’t know if this is too much to ask or not but if you can pretty much post a wiring diagram for both the ST zone controller and the Nest Thermostat. A basic sketch of both sides basically, I think I can handle it all. 

Otherwise, I will request a professional to come in.

Thank you. 

[CoolingWizard]

@smumur ,

Please keep in mind that using this work around I provided for your ST-2E, your second zone will not work properly if the primary thermostat is not calling for Heat or Cooling. There is another way to deal with this and this is to put a DPDT switch. This would allow you to set the ST-2E manually in Heating or Cooling mode. You would simply change the switch with the change of season.  

AC Cooling Wizard

[smumur]

@CoolingWizard , Understand...without main zone thermostat, we never operate the second zone thermostat...if the main zone is heating, then we need to heat the second zone or if main zone is cooling, then we need to cool the second zone. So, the work-around would be fine with me.

I just want to wire the work-around correctly. As mentioned above, i'd really appreciate if you could come up with a quick sketch on a piece of paper and post it as a picture or something for both the NEST and the ST zone controller. It would summarize all of this discussion.

Again, i hope it is not too much to ask. Take care.

[CoolingWizard]

@smumur ,

Here is an example how to wire your nest to the EWC ST-2E with workaround.  
,

AC Cooling Wizard