Thermostatic Controls - Connect Visionpro IAQ with Trane Comfortlink II AC and 24-V furnace

I have central AC and hydronic baseboard heat. Both were controlled with a standard VisionPro thermostat.

I just replaced my central AC with a new Trane XL19i (4TTZ0 with ComfortLink II) and variable speed air handler (4TEE3C07A1000A). The installer replaced my thermostat with a VisionPro IAQ since there were only 3-wires going to the stat from the AC. He did not connect the furnace to the AC so now I don't have heat. Fine in the summer...

How can I get the VisionPro IAQ thermostat to control both the AC and the furnace? Can I hook-up an IAQ EIM to the furnace and wire the 3-wires to the thermostat without shorting out the new AC controller? It looks like it should work (based on the wiring schematic for the optional telephone interface module) but I don't want to fry anything.

I just want to be clear, you got the Honeywell IAQ t-stat, NOT the Trane Comfortlink T-stat?

If it's the IAQ, 3 wires will only go to 1-2-3 on the t-stat, and it ties to the EIM (Equipment Interface Modular) near the air handler. On the EIM is where the boiler is hooked up to.

I have the Trane branded stat (I don't have the model number right now). So I want to hook up the Trane thermostat's 3 wires up to the EIM. Those wires are now connected to the air handler so ultimately I think I'll have 6 wires at the star - 3 from the EIM and the existing 3 wires from the AC.

I have the Trane branded stat (I don't have the model number right now). So I want to hook up the Trane thermostat's 3 wires up to the EIM. Those wires are now connected to the air handler so ultimately I think I'll have 6 wires at the star - 3 from the EIM and the existing 3 wires from the AC.

The Thermostat is Trane model TCONT900AC43UAA. There's also a Honeywell part number TH9431C1045.

I have the Trane branded stat (I don't have the model number right now). So I want to hook up the Trane thermostat's 3 wires up to the EIM.
Do you have this next to the air handler?
http://img43.imageshack.us/img43/6084/eimlores.jpg



Those wires are now connected to the air handler so ultimately I think I'll have 6 wires at the star - 3 from the EIM and the existing 3 wires from the AC.

Star?



The Thermostat is Trane model TCONT900AC43UAA. There's also a Honeywell part number TH9431C1045.

You have two t-stat?? or are you saying the two are the same?

Thanks Jay. Sorry for the confusion.

I only have 1 thermostat. I know Trane gets this thermostat from Honeywell and the TH9431C1045 part number is also included on the Trane thermostat. To me it looks like the Trane TCONT900 thermostat is similar to the VisionPro IAQ thermostat.

Anyway, the 3-wires from the thermostat are connected directly to the Trane air handler. The salesman said it was a "communicating system". It doesn't have the EIM box you show so that functionality must be built into the air handler.

The installer didn't know how to connect the boiler so he left that disconnected and suggested that I use a separate thermostat for the heat. I didn't want that so I was looking for a way to let the Trane thermostat talk to the boiler and the EIM looked like the solution.

What would you recommend?

Ok, now we are clear.. I was confused of what you all had.

I don't think we can tie the boiler to the the air handler. Unless we use a relay.

I may have to check with someone else and see what they say.

Ok, I got some what of an answer for you. I've asked around and kinda got an answer.

Since this has not been done we need you to use a meter to check something.

If it works as we planned, we need to add a relay to make this.

Do you have a meter to check some voltage reading for us?

Sure, just let me know what to measure.

Ok, on the board in the air handler, there is "ELEC HT". I am not sure if there is a wire on that or not.. But if there is a wire, follow that to where ever it goes to.

Take a reading on that when you put the system into heat mode. See if you get 24 volts on that or not.

You may have to program the t-stat to these settings.

172-1
176-1
180-0

Then turn on the heat mode and see what happens. As is aid earlier, this if the first time doing this so, we may have to play around with settings.

The thermostat wires connect to a terminal board with the following connections. I have a picture but can't upload them :(

BK, R, O, G, Y1, Y2 (There is a jumper connecting BK, R)
D, B, W1, W2, W3

The Thermostat is connected to R, D, and B.
The outdoor unit is connected to D and B.

I changed the setup values on the thermostat like you said so that "Heat" was an option. I measured voltage before and after turning on the heat but there was no change on the terminals. I checked between W1 and R, W1 and B. Zero between B and W1 and 27V between R and W1. Same readings for W2 and W3. Readings were the same whether heat was on or off.

I read the Trane installation manual and it said if the air handler is in communicating mode - using the communicating thermostat - then the other terminals would not be used. I guess that means not energized either.

I have a picture but can't upload them :(
The photos needs to be uploaded from a photo host site like imageshack.us, or yahoo. ect..


I read the Trane installation manual and it said if the air handler is in communicating mode - using the communicating thermostat - then the other terminals would not be used. I guess that means not energized either.

Guess that means we can't use the one t-stat for both heating and cooling.. so you'll have to use two t-stat then.