Its a Trane unit #YCD120C3LFA
never had one like this. first comp runs fine along with fan etc...
2nd stage wont start up. I replaced the Control board with a new one.
It will stage correctly when i jump it out in test mode
i was told the board controls the staging and the differential could be set on the board but it has not dip switches/jumpers on it
the low pressure switch is closed and does have adequate pressure in the lines, thats the only safety this thing has
it is wired into a trane tracker managment system, although ive never messed with one, i was told it shouldn't have anything to do with the unit staging, as it does come on with a call for cool
Are you getting control voltage to y2?
Besides test mode, have you tried jumping y1 and y2?
I believe the Voyager units decide when to run the 2nd stage cooling based on supply air temperature, if supply temp can be maintained with stage 1, stage 2 never comes on.
humm didnt think about that. i did check the outside air sensor and it showed the resistance it was supposed to. as i dont know much about trane (mostly all carrier for me) i didn't check those.. i dont really understand the stat inferface on this as there is the simple r,w,y1,y2 etc.
why does trane have to be different
You need to get you hands on "The Voyager Continues", aka the Black book. I know some of you guys have a link?
With a Tracker system you have a comm interface. That is your "stat", I guess. It communicates with the Tracker system to get set point and temperature. The UCP with stage according that input.
It might be that the setpoint and temperature are close. That is why 2nd stage isn't coming on. You could go and lower the setpoint on the Tracker. After 3 minutes, 2nd stage should call.
Best way to see if the UCP is calling for 2nd stage is 24v from J8-3 and J8-4.
Here is one source for the mentioned manual
http://www.scribd.com/doc/7038394/Tr...ontrols-Manual
I had an American Standard doing this to me the other day. The last safety switch in series to the contactor coil is the compressor overload located under the terminal cover. Mine had a bad terminal connection.
You have to fight through some bad days to earn the best days of your life.
You can learn something from EVERYONE.
disconnect the economizer module. check it for signs of moisture. voyager ucp units are famous for economizer modules getting wet through that little rectangular opening in the hood. the moisture will screw those boards and drive you crazy. it will create electrical noise that will make that ucp do all sorts of crazy things.
How is your air flow? I may be way off track here, but what is your supply air temp? If your air flow is low and your SAS is getting cold air, the unit will never go into 2nd stage. The unitary control doesn't know the room temperature, just the delta t of the unit itself. Doesn't Trane just treat the 2 stages as capacity control?
it was the econ. board, all it had going to it was a supply air sensor. once i pulled out the board and reset the unit stage 2 came on right when it was supposed to. although the unit has no econmizer (damper or actuator) i was told it was just there so the tracker system would know the supply air temp. that was the only sensor connected to the board.
ill grab a new board and sensor tomorrow
Thanks for letting us know what you found.
Was the board giving you a false reading on the return air temp or is it still in the 60s?