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  1. #1
    Join Date
    Dec 2012
    Posts
    8

    Can I install a standard thermostat on a Trane YSC060A3 rooftop unit?

    I just took over some ownership and maintenance duties on this temple in Atlanta. In one of the buildings there is 9 package rooftop units. They are all Trane units. They all seem to be these YSC060A3 style (some are the 48 model ones, smaller ones). Full model number is YSC060A3RMA2T01B. Each one of these units are directly connected to a single Trane Zone Sensor BAYSENS019C, so no multiple zone sensors connected to one unit. Now these zone sensors work fine, but we would like to change them all out to more user friendly ones, mainly also we want more control over them by using the Wifi based ones.

    Now when I took off the BAYSENS019C I noticed clearly this is not your normal thermostat wiring, it has the 7, 8, 9, 10, 11, 12, 14 labelled wires. Im like this is not a normal thermostat. After looking at manual noticed these dont operate like normal thermostats on those wires either, it uses mainly serial communication back to the control unit.


    So then I went to the roof and popped the control access panel off one of the rooftop units. Noticed the control board has those 7 through 14 wires connected, but also has the right side of the board where it has your standard pins like R, W, Y, G for a standard thermostat. But its unused. Here is a picture of that control board.


    Could I just say remove all the wires from 7-14 on the control board, and repurpose them on the right side of the control board to allow me to use a standard residential style thermostat (we are interested in installing the Filtrete 3M50s)? It seems straight forward to me, but wanted to check with some experts before attempting this.

    Dixit

  2. #2
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    6,839
    I think you have to install another board for those units to be able to use a standard 24v tstat. Don't get the 3m tstat, go with honeywell or Ecobee.

  3. #3
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    449
    That board is a Relatel board which is on the newer style Trane unit such as the Preditor series.
    Yes you can simply use a standard thermostat in place of the trane thermostat. No interface is necessary.

  4. #4
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    449
    Reliatel

  5. #5
    Join Date
    Dec 2012
    Posts
    8
    Quote Originally Posted by jtrammel View Post
    I think you have to install another board for those units to be able to use a standard 24v tstat. Don't get the 3m tstat, go with honeywell or Ecobee.
    I saw a 24v transformer above the board and that is also what on the label on the outside of the unit. So Im assuming that 24v can come off the board. The manual states that pin 11 and 14 are the power pins for the zone sensor. So I could tag one of those or just pull a wire straight to that 24v transformer. So I dont think I need another board. Heres the label (a little tough to read with the sunfade) off one of them. You can see where it says 24VAC on the control.



    Why dont you like the 3M50s? I personally have 4 in my house and 2 in another house, I like them so far especially at that price point. I know software very well so using the open APIs they have available on the thermostats to log various bits of data like run time, temp, status, etc. I thought those would be a good fit for the building as well as we can use one of the servers to constatly log data. We have some programmers that could also write a nice interface for a nice view of all thermostats and give control to certain individuals. We had two NEST tstats donated actually and after looking at those and researching them, it has a lot of nice features, but all that stuff wont really work for that building. We dont need the feature of it knowing when someone is "home" or "away". This is a building where its occupied alot by Monks and usually someone is always in that building. So that concept wont work. And then when you factor in we need 9 of them for this building alone, and then another 5 for another one, the cost will add up if we go with a NEST, or the Honeywell (I swear I saw that one at like $200+ at home depot for the touchscreen one).

    Dixit

  6. #6
    Join Date
    Dec 2012
    Posts
    8
    Quote Originally Posted by alcomech View Post
    That board is a Relatel board which is on the newer style Trane unit such as the Preditor series.
    Yes you can simply use a standard thermostat in place of the trane thermostat. No interface is necessary.
    Thats great. Thats what I figured when I saw those extra residential style screw pin labelled R,Y, W, G. I researched this a few days earlier (when I just pulled the zone sensor off the wall) and most on this forum were saying to use a standard thermostat you would need an expansion/addon board. But once I pulled that control access panel, I had a good hunch that I was probably good to go in just swapping the wires over and use the 24vac (which most of these wifi thermostats need to power the wifi module) off the transformer or off the board itself.

    Dixit

  7. #7
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    449
    Do not confuse this Reliatel board which you have with the older series Microtel board which was on the Voyager units.
    Its true that the Microtel used an interface "CTI" conventional thermostat interface, but is not required on the Reliatel board.

    As for the connections DO NOT use any of the previous terminals as they are not conventional connections for any thermostat except a Trane Thermostat on zone sensor.

    As for the common you will simply connect the common on the terminal strip. Do not connect to the transformer.

  8. #8
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    449
    or zone sensor

  9. #9
    Join Date
    Dec 2012
    Posts
    8
    Yeap got it. I was planning on wiring this straight up on the right side only by using only 5 wires. Just use R, W1, Y1 G, and the COM for the C wire for the 3M50 thermostat. That should do it, the remaining 3wires will just end up being tucked away. Will test run this for a few days on just one unit, if its good, then will proceed and do the same for the other 8 on this building then work on the other buildings.

    Dixit

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