Need help installing Trane thermostat

Other Devices & Integrations Climate Control & Temperature Sensors
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I am in the process of installing the Trane TZEMT400BB32MAA thermostat and have a question. I followed the instructions that came with the device and all was well until I got to Step 12. Here is my current situation.

I have a Trane heat pump, model 4TEC 3F4BB 1000AA, that is being controlled by a Braeburn model 5000, 5-2 programmable thermostat.

Reviewing the documentation for the Braeburn and the Trane models I find some inconsistencies that I must resolve. The Braeburn quick wiring terminal block has eight connections:

RC RH B O Y W G C

The corresponding Trane quick wiring terminal block also has eight connections:

24RC G Y1 Y2 24C 24RH W1 W2

The Braeburn wiring has a strap between RC and RH. There are five conductors coming through the wall. These are red, blue, yellow, white and green. Per instructions, these are now tagged according to the Braeburn connectors they are attached to as follows:

RH O Y W G

My question is do I need to strap any points on the Trane connector block as was done on the Braeburn thermostat? Perhaps the RC to RH strap.

In step 12, of the installation instructions a note directs:

“A wire must be connected to “24C” to power the thermostat”.

There is no 24C terminal or wiring on the Braeburn, presumably because it uses two AA batteries to run. So I am left with the question of exactly which wire to connect to 24C on the Trane thermostat. Step 12 also cautions against improper wiring which can damage equipment.

I need clarification of the Trane installation instructions. Although the heat pump seems to have been working well for many months I want to insure the installation of the new Trane thermostat will be correct and nothing gets damaged, including my ego.

Your help is appreciated. I sent an email to a local Trane office, but so far have not received a reply. Frankly I get the impression Trane is not eager to deal directly with users of their products. Does anyone else feel this way?

2

[quote=“GoingGreen, post:1, topic:181053”]My question is do I need to strap any points on the Trane connector block as was done on the Braeburn thermostat? Perhaps the RC to RH strap.[/quote] The trane thermostat already has a built in jumper between RC and RH it talks about it in the instructions and its actually located on the backside of the thermostat (on the circut board in the lower right corner if I remember) its not on the wiring panel that’s screwed to the wall. If you don’t want that you have to cut the jumper, but it’s there from the factory.

[quote=“GoingGreen, post:1, topic:181053”]“A wire must be connected to “24C” to power the thermostat”.

There is no 24C terminal or wiring on the Braeburn, presumably because it uses two AA batteries to run. So I am left with the question of exactly which wire to connect to 24C on the Trane thermostat. Step 12 also cautions against improper wiring which can damage equipment.[/quote]

not haveing the 24C or common, is quiet common… (see what I did there, LOL) Since these need constant power and ground (common) to power them and most other don’t. In my application I had enough wires in the wall (few empty) but I had to connect one on the furnace or air handler side to the common. Youll see somewhere in or on the airhandler (or in the instructions mounted somehwere on it) there is a 120 volt 2 wire input that goes threw a transformer and has 2 wires comming off them. One if the 24v power wires are going to the RC/RH and the other is the common that you need to get back to the 24C. This wire will already be heading out to your heatpump or ac outside but you now need to splice it to your thermostat too.

Again for me this just ment going to the airhandler and connecting a wire that was unsed before to both the right spot in the airhandler and the thermostat.

3

You’re going to have to be sure you handle the reversing valve correctly on the new thermostat (the ‘O’ wire). Do you have aux heat? You should be able to find a wiring diagram that matches your system.
The batteries on the existing thermostat are likely for backup of the settings, not to run the thermostat. No getting around having a common wire on zwave thermostats. You either going to have to wire it in or not use the Trane (which I believe can not run on batteries).
My remotec thermostats ran on batteries until I could wire a common. But it was designed with that option.
The lack of a common in thermostat wiring is the usual way thermostats seemed to be wired, at least in the U.S.
Trane expects you to use a service call from a Trane dealer if you have problems. Considering you have a heat pump, paying someone to install it right might be the best approach.

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[quote=“dzmiller, post:3, topic:181053”]You’re going to have to be sure you handle the reversing valve correctly on the new thermostat (the ‘O’ wire). Do you have aux heat? You should be able to find a wiring diagram that matches your system.
The batteries on the existing thermostat are likely for backup of the settings, not to run the thermostat. No getting around having a common wire on zwave thermostats. You either going to have to wire it in or not use the Trane (which I believe can not run on batteries).
My remotec thermostats ran on batteries until I could wire a common. But it was designed with that option.
The lack of a common in thermostat wiring is the usual way thermostats seemed to be wired, at least in the U.S.
Trane expects you to use a service call from a Trane dealer if you have problems. Considering you have a heat pump, paying someone to install it right might be the best approach.[/quote]

The heat pump shouldn’t be a problem as everything matches from one thermostate to the next minus the common. Only other thing after is you need to get into the secret menu (lol) to set the right setting for heat pump and such but that also isn’t hard.

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Did he just leave off the orange in his wiring chart?

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I don’t see where it says he did… The “O” doesn’t necessary have to be orange either. But the old and new thermostats wiring is the same except for the 24C which the old thermostat doesn’t have. Jumpers are already in place

The settings are different tho, but he hasn’t got to that and it’s worded out so I don’t see it begin a big problem. You just need to tell it what you have hooked up.

I have 7 Trane tzemt500’s and two of them (in a vacation house) replace Braeburn 3000’s. My airhandlers were in the attic both of them (2 separate heat pump/ac only systems in this Arizona house) only problem is I needed to add the 24C wire.

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Thanks to all for the information. Unfortunately, I cannot confidentially interpret all the questions because I lack the technical knowledge to do so. At this point I think it is best I get an expert. In the past, I did contact an HVAC technician but he said he would not install the thermostat for me. I don’t recall exactly what his reasons were, but that was his policy.

I live in Glendale AZ, close to downtown Phoenix. If anyone can suggest a more open minded tech to call I would be grateful. You may be wondering why I don’t call the contractor that installed my system, but I did not a have good experience back then. Perhaps I should give them another shot. I am retired, living on social security and this is why I attempt to do as much work myself as possible.

I can go ahead and kill power to the system and remove the wiring to the Braeburn connectors, which like I say are all tagged. Then I can dismount the Braeburn wall bracket, attach the Trane wall bracket and pull the cable bundle through the bracket.

Then the technician can make the final wiring connections as applicable to my installation. I think this is the safest way for me to proceed assuming I can locate an agreeable technician. Writing to the forum helps me clarify my thinking and I receive good advice and don’t feel quite so lost. Thanks to all.

While I was composing this dzmiller and integlikewhoa were responding to my original post. The “O” conductor is actually blue. Still not clear on the concept of the 24C conductor and now questioning how to “tell it what you have hooked up”.

Programming the thermostat is yet to be surmounted.

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[quote=“GoingGreen, post:7, topic:181053”]While I was composing this dzmiller and integlikewhoa were responding to my original post. The “O” conductor is actually blue. Still not clear on the concept of the 24C conductor and now questioning how to “tell it what you have hooked up”.

Programming the thermostat is yet to be surmounted.[/quote]

That’s completely understandable and we are here to help, not get you into something you can’t get out of.

24C is going to be the hardest part of this wiring. Do you even have any unused wires in the wiring? You said you have 5 conductors coming threw the wall. Is all of these 5 currently hooked up? If they are then your going to have a bigger problem as you’ll need a 6th to connect the 24C (24v common) to on each end.

To try and explain it a little better. A normal light switch only has a hot wire comming in, then a wire comming out with a switched hot either on or off depending on the switch. I light bulb has a this wire plus a common wire that’s hooked up permanently. The a/c is the same way but with 24v’s instead of 110v.

Your old thermostat only had 24v power comming in and then going out on different wires to kick on the a/c, heater or fan. Each of those devices already had a constant 24v common going to them and just needed the power side to complete the circut. Well this z-wave thermostat now needs a constant common just like the rest of the devices so it can power its self up all the time. So you need an extra wire that you don’t currently have going to it. Most cases you have a 5 or 7 strand conductor running to the thermostats with a few unused wires since not every house uses the full amount depending on systems.

Let us know how many wires you have there is some aftermarket add a wire kits that might work if running a new wire is an issue.

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[quote author=integlikewhoa link=topic=24964.msg174851#msg174851 date=1399491435]

[quote=“GoingGreen, post:7, topic:181053”]Let us know how many wires you have there is some aftermarket add a wire kits that might work if running a new wire is an issue.

So far as I can see the cable running from the air handler to the thermostat only has five wires, unless one is clipped back where I cannot see it. I’ll have to shut off the circuit breaker and pull the cable out a ways from the wall.

The air handler is in a small space that used to hold the gas furnace. Only a few inches separate the space between the air handler and the thermostat.

All five wires are currently connected to the Braeburn quick wiring block (see opening post).

If I understand what you are saying i actually need six wires for the Trane. Is that correct? The device you suggest is meant to overcome a wiring problem that could extend many feet, which is not my situation. It would be less expensive to simply replace the existing cable with one that has the needed conductors.

This entails rewiring the air handler end of the connections. And that is yet another hurdle, but I have not looked at that so maybe it is not as bad as I imagine. If all the connections go to a single connecting block it should not be difficult to replace the cable.

I guess my next step is to investigate the air handler. BTW I did check on the contractor that installed my system and found they were out of business. Recalling some of the details of that installation, I do remember that I insisted they take out the thermostat they originally installed and supply a programmable model. Which they did. It is not a bad unit, but my issue is the difficulty I have using it because the display is so tiny and the steps to program it are tedious. With the Trane I will be able to make changes at the computer or even using my Nexus 7 IdeaPad anywhere in the house. I also plan on incorporating a near field sensor in a location where I can switch the AC off when I go out of the house. I assume I will have a Home and an Away scene. Details of this remain to be worked out.

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[quote=“GoingGreen, post:9, topic:181053”]So far as I can see the cable running from the air handler to the thermostat only has five wires, unless one is clipped back where I cannot see it. I’ll have to shut off the circuit breaker and pull the cable out a ways from the wall.

The air handler is in a small space that used to hold the gas furnace. Only a few inches separate the space between the air handler and the thermostat.

All five wires are currently connected to the Braeburn quick wiring block (see opening post).

If I understand what you are saying i actually need six wires for the Trane. Is that correct? The device you suggest is meant to overcome a wiring problem that could extend many feet, which is not my situation. It would be less expensive to simply replace the existing cable with one that has the needed conductors.

This entails rewiring the air handler end of the connections. And that is yet another hurdle, but I have not looked at that so maybe it is not as bad as I imagine. If all the connections go to a single connecting block it should not be difficult to replace the cable.

I guess my next step is to investigate the air handler. BTW I did check on the contractor that installed my system and found they were out of business. Recalling some of the details of that installation, I do remember that I insisted they take out the thermostat they originally installed and supply a programmable model. Which they did. It is not a bad unit, but my issue is the difficulty I have using it because the display is so tiny and the steps to program it are tedious. With the Trane I will be able to make changes at the computer or even using my Nexus 7 IdeaPad anywhere in the house. I also plan on incorporating a near field sensor in a location where I can switch the AC off when I go out of the house. I assume I will have a Home and an Away scene. Details of this remain to be worked out.[/quote]

Yes you need a 6th wire and yes if your talking other side of wall is a the thermostate then you got it easy. Some of us have air handlers/ heaters in attic of 2 story house and thermostat could be 1st floor on the other side of house. To not make anything harder then it already is you don’t even have to replace all the wires that are there, just get yourself a few feet of thermostat wire 2 conductor or what ever and just run it next to the old and use 1 wire out of it.

The thermostat wires should go back into the airhandler and with a few pictures or even the model of that unit we can identify the 24C, or common wire that needs to be connected. The 24C or common wire will already be in use atleast going to the outdoor A/C unit. We will have to unwire nut it and add this wire to this connection also.

Most air handlers if not all will have a wiring diagram or instructions printed on the inside or outside of the door. That is if its not 20 years old and ripped off by now.

11

Ok, things are starting to clarify and my confidence is building. Next step seems to be to pin down the wiring inside the air handler. You are right it would be easier to just leave the existing wires as they are installed on the air handler side and add a single conductor for the common to 24c on the thermostat.

The manufactured date of the air handler is 11/2010. Model was documented in my opening post. I can send a photo if you think that would be helpful.

I don’t know how to answer the question about “aux heat”. How would I determine if I have that?

Looking ahead, you allude to a “secret” menu. That has me curious. Could you elaborate about this?

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[quote=“GoingGreen, post:11, topic:181053”]Ok, things are starting to clarify and my confidence is building. Next step seems to be to pin down the wiring inside the air handler. You are right it would be easier to just leave the existing wires as they are installed on the air handler side and add a single conductor for the common to 24c on the thermostat.

The manufactured date of the air handler is 11/2010. Model was documented in my opening post. I can send a photo if you think that would be helpful.

I don’t know how to answer the question about “aux heat”. How would I determine if I have that?

Looking ahead, you allude to a “secret” menu. That has me curious. Could you elaborate about this?[/quote]

Model number would be best if not pictures of the wiring connections inside the air handler might do.

AUX heat is a heater besides the heat-pump, and since your in Arizona like my vacation house I’m going to bet you don’t have that. AUX heat is a gas or electric heater that kicks on when the heat pump can’t keep up… IE it’s to cold outside for the heat pump to be efficient (which Arizona never gets cold like back east or up north) Plus wiring is the same as your old system only difference is done in the settings menu.

Secret menu is not so secret but you have to hold down the 2 center buttons to get into the detailed settings. In there you will set heat pump or not, aux heat or not. Single or dual stage heat or A/C and a few more. The secret is not so secret as it’s written in the installation manual, but you won’t need any of this until you get the common hooked up so the thermostat will actually power up.

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Ok, on aux heat the answer is no. Don’t have that feature. The air handler model is:

4TEC 3F4BB 1000AA which I inappropriately identified as the “heat pump”. Wasn’t thinking clearly.

I can open it up and take pictures later today. There is no wiring diagram on the outside. Would be nice to find some documentation on the web so will look there.

Thanks for everything.

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A little background.
What the color coded wires mean:
RH - Power Heat
RC - Power Cool
O - Heat Pump Heat/Cool change Over
G - Inside Fan Control
Y - 1st Stage Cooling
W - 1st Stage Heating
C - Power Common

For a standard single stage heat/cool setup you need 6 wires … for the Z-Wave thermostat. Most use the same transformer for Heat and Cool so the RH and RC are internally (to the thermostat) connected.

The 5 wires you currently have go to the same color codes on the Trane thermostat.

You may have to make one change on the thermostat … you have a 50/50 chance that it is setup properly.
Different Heat pumps power the O wire differently … Some power it for heat, some for cooling.
There is a setting in the thermostat to configure this if it is not working correctly. (You will know … if it heats in the summer and cools in the winter).

However you need to have 6 wires. Your previous thermostat did not consume any power. The new thermostats need some power because of the Z-Wave radio and computer for used for managing the thermostat schedules etc. As a result you need an additional wire. You have two option:

  1. Replace the 5-wire thermostat wire with a 6 a wire conductor (I would probably replace it with 7 or 8 conductor
    At the air handler (after turning off the power) replace the 5 wire conductor using the same color scheme as the current setup.
    Pick a color for the 6th wire out of the remaining conductors. Find the 24 volt transformer. There will be two connectors. Hook the wire up to one of them … and C on the Thermostat. Turn the power on … if the thermostat does not turn on … turn the power off … and hook that wire to the other connector on the transformer. (You will not hurt anything if you do the wrong one first).

  2. Another option if it’s too painful to replace the 5 wire conductor is to run an additional 2 wire conductor to some place you can add a second transformer. This will need to be a place where you can access power all of the time. Get a 24V transformer. Something like:
    http://www.ebay.com/itm/24V-AC-8A-Tyco-Transformer-Plate-Mounted-Screw-Terminals-24VAC-20VA-PowerSupply-/221336337850?pt=PCA_UPS&hash=item3388ac7dba
    Two wire conductors are usually have a red and white wire. Hook the two wires on the transformer (24V Volt Side) and the red wire to RC or RH (which ever one you are not currently using … remember these are connected internally).
    And the white wire goes to the C wire.

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Thanks Richard for the clarifying info. I think I will go with option 1. Should not be too difficult to locate the transformer inside the air handler and dressing/stripping wires is not that big a job. A single cable makes for a neater approach.

I’m getting a real education from all the replies people have kindly offered. I do greatly appreciate the help.

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[quote=“GoingGreen, post:13, topic:181053”]Ok, on aux heat the answer is no. Don’t have that feature. The air handler model is:

4TEC 3F4BB 1000AA which I inappropriately identified as the “heat pump”. Wasn’t thinking clearly.

I can open it up and take pictures later today. There is no wiring diagram on the outside. Would be nice to find some documentation on the web so will look there.

Thanks for everything.[/quote]

Your model number is off by one and google gave me a hard time about it. LOL 48 not 4B in the middle which is the ton size of your unit which is 4 Ton by the way.

So you have a TRANE 4TEC3F48B1000AA

Here’s a online manual, but you should find when you open the big access door on the unit it’s also mounted on the inside. ( I also have a trane air-handler, but different model)

I have attached the wiring diagram below, one un molested and the other I have circled the 120 to 24v transformer and traced over the common wire as it leads down to the connection block. The wire is BLUE inside the Air Handler and you’ll notice coming out the transformer the power wire is red with a fuse 5 amp fuse before it gets to the connection block.

These two wires ultimately have to get to the RC/RH and C on the thermostat to power it up.

Judging by the info you gave us and the and the old thermostat connections I don’t think any of this below really applies but I’ll throw it out for more info or to double check anyways.

I’m very curious about the BLUE wire in the wall hooked up to “O” on the thermostat and would like to have more info on which wires go to where when you open the door on the Airhandler. Just want to make sure it doesn’t go to the Blue wire inside the Air handler.

Reason is because without a heater and only single stage cooling and heating you really don’t need 6 wires. In my Arizona house they powered the “O” and the “W” heating together (inside the air handler they were twisted together). They did this since there is no actual heater and anytime to turn on the heater “W” it powers the reverse valve at the same time and only at the same time. I can only assume yours might be the same, but don’t think so based on your first post wiring description.

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While searching the web for an electrical diagram of my air handler I quickly discovered a wealth of information about thermostat wiring that applies to heat pumps. YouTube has many videos produced by HVAC technicians. I got a lot out of viewing the videos.

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So did you get it installed?

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Yesterday I opened the air handler cabinet and did not like what greeted me. A tangle of wires connected with wire nuts. I’ll try to capture a clear photo to attach.

Looking at the existing cabling I am changing my mind about installing a new cable, instead I will just have to find the correct wire to route to the new thermostat, if needed. I did find the air handler documentation pasted inside the cover. Sorry about the mistaken part number I originally posted.

Integlikewhoa, I am not following your comment about the diagram.

“I have attached the wiring diagram below, one un molested and the other I have circled the 120 to 24v transformer and traced over the common wire as it leads down to the connection block.”

Did you forget to attach the diagram? By “connection block” I am assuming you mean the “polarized plug”.

In any case if what I now understand you saying is true the point is moot. I don’t need six wires.

Tracing the blue conductors I see the connection to the polarized plug (6) from a relay contact inside a closed housing.

There are two identical five conductor cables: one goes to the thermostat and the other leads outside. Colors are white, green, yellow, blue and red.

The blue conductor in the thermostat cable is connected to the white conductor in the outside cable.

Notes:
photo 1445 is the Braeburn connector block
photo 1440 v2 is a cropped version of the polarized plug and associated cabling

I am running up against limits of photo size I can post. Let me know if these photos help.

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[quote=“GoingGreen, post:19, topic:181053”]Integlikewhoa, I am not following your comment about the diagram.

“I have attached the wiring diagram below, one un molested and the other I have circled the 120 to 24v transformer and traced over the common wire as it leads down to the connection block.”

Did you forget to attach the diagram? By “connection block” I am assuming you mean the “polarized plug”.[/quote]

No I attached 2 files in that post and as you have found they match the one in your 2nd picture.

I’m assuming the one lower in the pic is the one going to the thermostate. The higher one is going outside to the a/c unit.

Are you sure it looks like in the picture the blue in the air handler is wire nutted to the blue going to the inside thermostat. Hard to tell as the red wires are in front blocking the picture.

And you post one or two more pictures with the wires moved around a bit to show me which colors are going to where from both the outside ac and the thermostat

Also the way they have it wired it doesn’t look like you’ll need the 6th wire and it looks so far (waiting for pictures to confirm) that the 24C wire is already hooked up in the air handler to the blue going to the thermostat. So it just might be a matter of putting blue to the 24c in the thermostat and your done.

I specifically right now need to see better shots of the which wires are going to the outside a/c unit. The white wire coming from the thermostat (the heat wire) is wire nutted to?