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Thread: Trane Varitrac

  1. #1
    Join Date
    Jul 2005
    Location
    Birmingham, AL.
    Posts
    28
    We just took over a new account. System is a Trane Voyager 30 ton with inlet vanes. There is 17 boxes, some parallel fan boxes, some series, all with heat. When we arrived the CCP was in priority shutdown with no communication to any device. we discovered that the bus polarity was reversed at a junction box above the ceiling?? Once corrected we were able to communicate with most of the boxes (all but three). We fixed one box that we could not get to communicate by replacing the UCM. Polarity was reversed at this box also. With a section of the box bus disconnected (about 5 boxes) the CCP will intermittently communicate with the unit. The CCP will display fan status and supply air temperature, compressor status, etc. for 10-15 seconds then the info changes to question marks. After about a minute the information is diplayed again and drops off again. The unit stays onlne. The first tech replaced the TCI board in the unit under warranty. Trane had replaced it a short time ago. This made no difference.

    When we found the polarity issues we went to every box to check bus polarity and addresses. We found no other issues. We did notice that the communication bus was wired to the sensors. This wire is not shielded.

  2. #2
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,152
    Is there a terminating resistor somewhere?

  3. #3
    Join Date
    Jul 2005
    Location
    Birmingham, AL.
    Posts
    28
    Not to my knowledge. Is that used on comm 4 devices?

  4. #4
    Join Date
    Nov 2004
    Location
    Practically Canadian ehh.
    Posts
    675
    Comm4 links are prone to electrical interference issues without proper shielding. Wiring down to each zone sensor (t-stat) adds length and opens the doors to additional interferce problems. Check the connections, and check for any nicks in the wire. Try disconnecting the comm link wires to each sensor. The reality is you only need one or two strategically placed sensors that are connected to the link. And you will need Rover Comm4 to make use of the jack in the sensor that is wired to the link. If the link wiring is unshielded then you might want to consider replacing it. Trane recommends shielded wire for that link.

  5. #5
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,152
    Had a job a couple of years ago with a Tracker (comm4). Nine Voaygers and 2 Precedents. One Precedent would continuously go 'offline' and then come back a short while later. Trane tech support said 'the Precedents are subject to that problem with no EOL resistor", said the Voyagers were not as sensitive. I added the resistor and the problems went away.

    Not sure about your particular problem but I would go with kwillmech's suggestions first.

  6. #6
    Join Date
    Jul 2005
    Location
    Birmingham, AL.
    Posts
    28
    As of now our plan for Tommorrow is to connect each of the boxes we currently have disconnected one at a time to see if this changes anything. We also plan to disconnect the bus going to the sensors.

    What does Trane use for EOL resistors? I have never installed them on a Trane system.

  7. #7
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,152
    Old Tracker manual says.... "If the wire length on a daisy chain configuration exceeds 2,500 feet, install a 100-ohm termination resistor at the far end of the commuication link. If the wire length is less than 800 feet, install a 300-ohm (or 270 to 300-ohm) termination resistor at the far end of the communication link. If you use the star configuration, you may need to install a 300-ohm (or 270 to 300-ohm)termination resistor at the end of each branch. The maximum number of branches is 10."

    This refers to the communication link between the Voyager and the Varitrac II CCP or Tracker, not the CCP and the UCMs. An old CCP installation manual makes no reference to an EOL resistor in the comm link between the CCP and UCMs.

  8. #8
    Join Date
    Jul 2005
    Location
    Birmingham, AL.
    Posts
    28
    Thanks Dapper. I appreciate everyones help. I have always received good advice from this site.

    Trane is limiting their support since we are taking this account from them. Makes you want to buy their products. HaHa.

    I will let you know how it goes.

  9. #9
    Join Date
    Nov 2004
    Location
    Practically Canadian ehh.
    Posts
    675
    Amazing they would want it. Tracer/Varitrac is light commercial and we get everyone and their brother installing them around here. Everytime we ge involved it's because some contractor installed it and didn't bother to read the installation literature. They figured its just like every other zoning system they put in and must be wired the same too. Then the shiit doesn't work and they cry to their Trane salesman for help! We get to go pick up the pieces for the salesman and get paid squat burden labor rate by the salesman. We can't even compete with the labor rates the contractors charge for servicing these systems. Again, surprised the local Trane office cares if you take it.

  10. #10
    Join Date
    Jul 2005
    Location
    Birmingham, AL.
    Posts
    28
    We do alot of industrial maintenance and so does the local Trane office. This system serves the office area. They also have 500-600 tons of intellipacks and are building an expansion. The customer is fed up with Trane's service and with their inability to fix the problem. This I found surprising since I know some of these guys and my impression was that they were top notch. I believe Trane installed this system. Of course this means that they sub it to an electrical contractor and just do the programming.
    The local Trane office has done a good job of keeping contractors in the dark with Summit and Tracer. When projects are bid if you want a Summit systems you pay Trane to install it.

    I don't understand there problem with fixing this system. Of course the customer has said it never worked right. I take those comments with a grain of salt until I get to the root of the problem.

  11. #11
    Join Date
    Jul 2005
    Location
    Birmingham, AL.
    Posts
    28
    OK Fellas, The system is up and running. We removed all un-shielded comm links connected to the sensors, checked all shield connections (found 1 not connected midway of the comm link for a total of 3). We also installed a 100 ohm resistor at the end of the link (thanks Dapper.). The comm link is pretty long. We removed the resistor to see how it would work without it and started to get priority shutdown alarms, re-installed the resistor and it cleared up. Anyway thanks to all.

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